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Apollo 14	Table of Content	Short description, Astronauts and key Mission Control personnel, Preparation and training, Hardware, Spacecraft, Launch vehicle, ALSEP and other lunar surface equipment, Modular Equipment Transporter, Mission highlights, Launch and flight to lunar orbit, Lunar orbit and descent, Lunar surface operations, Lunar samples, Lunar orbit operations, Return, splashdown and quarantine, Mission insignia, Spacecraft locations
Apollo 15	Short description	Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the Apollo program and the fourth Moon landing. It was the first J mission, with a longer stay on the Moon and a greater focus on science than earlier landings. Apollo 15 saw the first use of the Lunar Roving Vehicle. The mission began on July 26 and ended on August 7, with the lunar surface exploration taking place between July 30 and August 2. Commander David Scott and Lunar Module Pilot James Irwin landed near Hadley Rille and explored the local area using the rover, allowing them to travel further from the Lunar Module than had been possible on previous missions. They spent 18 hours on the Moon's surface on four extravehicular activities (EVA), and collected of surface material. At the same time, Command Module Pilot Alfred Worden orbited the Moon, operating the sensors in the scientific instrument module (SIM) bay of the service module. This suite of instruments collected data on the Moon and its environment using a panoramic camera, a gamma-ray spectrometer, a mapping camera, a laser altimeter, a mass spectrometer, and a lunar subsatellite deployed at the end of the moonwalks. The Lunar Module returned safely to the command module and, at the end of Apollo 15's 74th lunar orbit, the engine was fired for the journey home. During the return trip, Worden performed the first spacewalk in deep space. The Apollo 15 mission splashed down safely on August7 despite the partial opening of one of its three parachutes. The mission accomplished its goals and also saw the collection of the Genesis Rock, thought to be part of the Moon's early crust, and Scott's use of a hammer and a feather to validate Galileo's theory that when there is no air resistance, objects fall at the same rate due to gravity regardless of their mass. The mission received negative publicity the following year when it emerged that the crew had carried unauthorized postal covers to the lunar surface, some of which were sold by a West German stamp dealer. The members of the crew were reprimanded for poor judgment, and did not fly in space again.
Apollo 15	Background	Background In 1962, NASA contracted for the construction of fifteen Saturn V rockets to achieve the Apollo program's goal of a crewed landing on the Moon by 1970; at the time no one knew how many missions this would require. In 1969 Apollo 11 succeeded in landing on the Moon with the sixth SaturnV, so nine rockets remained available for a hoped-for total of ten landings. These plans included a heavier, extended version of the Apollo spacecraft to be used in the last five missions (Apollo 16 through 20). The revamped Lunar Module would be capable of up to a 75-hour stay, and would carry a Lunar Roving Vehicle to the Moon's surface. The service module would house a package of orbital experiments to gather data on the Moon. In the original plan Apollo 15 was to be the last of the non-extended missions to land in Censorinus crater. But in anticipation of budget cuts, NASA cancelled three landing missions by September 1970. Apollo 15 became the first of three extended missions, known as J missions, and the landing site was moved to Hadley Rille, originally planned for Apollo 19.
Apollo 15	Crew and key Mission Control personnel	Crew and key Mission Control personnel
Apollo 15	Crew	Crew Scott was born in 1932 in San Antonio, Texas, and, after spending his freshman year at the University of Michigan on a swimming scholarship, transferred to the United States Military Academy, from which he graduated in 1954. Serving in the Air Force, Scott had received two advanced degrees from MIT in 1962 before being selected as one of the third group of astronauts the following year. He flew in Gemini 8 in 1966 alongside Neil Armstrong and as command module pilot of Apollo 9 in 1969. Worden was born in 1932 in Jackson, Michigan, and like his commander, had attended West Point (class of 1955) and served in the Air Force. Worden earned two master's degrees in engineering from Michigan in 1963. Irwin had been born in 1930 in Pittsburgh, and had attended the United States Naval Academy, graduating in 1951 and serving in the Air Force, receiving a master's degree from Michigan in 1957. Both Worden and Irwin were selected in the fifth group of astronauts (1966), and Apollo 15 would be their only spaceflight. All three future astronauts had attended Michigan, and two had taken degrees from there; it had been the first university to offer an aeronautical engineering program. thumb\|right\|alt=Two men with large backpacks stand amid a desert landscape\|Gordon (right) and Schmitt during geology training The backup crew was Richard F. Gordon Jr. as commander, Vance D. Brand as command module pilot and Harrison H. Schmitt as Lunar Module pilot. By the usual rotation of crews, the three would most likely have flown Apollo 18, which was canceled. Brand flew later on the Apollo–Soyuz Test Project and on STS-5, the first operational Space Shuttle mission. With NASA under intense pressure to send a professional scientist to the Moon, Schmitt, a geologist, was selected as LMP of Apollo 17 instead of Joe Engle. Apollo 15's support crew consisted of astronauts Joseph P. Allen, Robert A. Parker and Karl G. Henize. All three were scientist-astronauts, selected in 1967, as the prime crew felt they needed more assistance with the science than with the piloting. None of the support crew would fly during the Apollo program, waiting until the Space Shuttle program to go into space.
Apollo 15	Mission Control	Mission Control The flight directors for Apollo 15 were as follows: Gerry Griffin, Gold team Milton Windler, Maroon team Glynn Lunney, Black team Gene Kranz, White team During a mission the capsule communicators (CAPCOMs), always fellow astronauts, were the only people who normally would speak to the crew. For Apollo 15, the CAPCOMs were Allen, Brand, C. Gordon Fullerton, Gordon, Henize, Edgar D. Mitchell, Parker, Schmitt and Alan B. Shepard.
Apollo 15	Planning and training	Planning and training Schmitt and other scientist-astronauts advocated for a greater place for science on the early Apollo missions. They were often met with disinterest from other astronauts, or found science displaced by higher priorities. Schmitt realized that what was needed was an expert teacher who could fire the astronauts' enthusiasm, and contacted Caltech geologist Lee Silver, whom Schmitt introduced to Apollo 13's commander, Jim Lovell, and to its Lunar Module pilot, Fred Haise, then in training for their mission. Lovell and Haise were willing to go on a field expedition with Silver, and geology became a significant part of their training. Geologist Farouk El-Baz trained the prime crew's command module pilot, Ken Mattingly to inform his planned observations from lunar orbit. The crew's newly acquired skills mostly went unused, due to the explosion that damaged the Apollo 13 spacecraft, and caused an abort of the mission. Apollo 14's CMP, Stuart Roosa, was enthusiastic about geology, but the mission commander, Shepard, less so. thumb\|left\|alt=Film taken from lunar rover trainer\|Scott and Irwin train to use the rover Already familiar with the spacecraft as the backup crew for Apollo 12, Scott, Worden and Irwin could devote more of their training time as prime crew for Apollo 15 to geology and sampling techniques. Scott was determined that his crew bring back the maximum amount of scientific data possible, and met with Silver in April 1970 to begin planning the geological training. Schmitt's assignment as Apollo 15's backup LMP made him an insider, and allowed him to spark competition between the prime and backup crews. The cancellation of two Apollo missions in September 1970 transformed Apollo 15 into a J mission, with a longer stay on the lunar surface, and the first Lunar Roving Vehicle (LRV). This change was welcomed by Scott, who according to David West Reynolds in his account of the Apollo program, was "something more than a hotshot pilot. Scott had the spirit of a true explorer", one determined to get the most from the J mission. The additional need for communications, including from planned experiments and the rover, required the near-rebuilding of the Honeysuckle Creek Tracking Station in Australia. thumb\|upright\|alt=Man around age 40 with sunglasses and a large backpack takes a photograph with a camera mounted on his chest\|Commander David Scott takes a photograph during geology training in Hawaii, December 1970 Geology field trips took place about once a month throughout the crew's 20 months of training. At first, Silver would take the commanders and LMPs from the prime and backup crews to geological sites in Arizona and New Mexico as if for a normal field geology lesson, but closer to launch, these trips became more realistic. Crews began to wear mock-ups of the backpacks they would carry while hiking near the Rio Grande Gorge, and communicate using walkie-talkies to a CAPCOM in a tent. The CAPCOM was accompanied by a geologist unfamiliar with the area who would rely on the astronauts' descriptions to interpret the findings, and familiarized the crew members with describing landscapes to people who could not see them. Considering himself a serious amateur, Scott came to enjoy field geology. The decision to land at Hadley came in September 1970. The Site Selection Committee had narrowed the field down to two sites—Hadley Rille, a deep channel on the edge of Mare Imbrium close to the Apennine mountains or the crater Marius, near which were a group of low, possibly volcanic, domes. Although not ultimately his decision, the commander of a mission always held great sway. To David Scott the choice was clear, as Hadley "had more variety. There is a certain intangible quality which drives the spirit of exploration and I felt that Hadley had it. Besides it looked beautiful and usually when things look good they are good." The selection of Hadley was made although NASA lacked high resolution images of the landing site; none had been made as the site was considered too rough to risk one of the earlier Apollo missions. The proximity of the Apennine mountains to the Hadley site required a landing approach trajectory of 26 degrees, far steeper than the 15 degrees in earlier Apollo landings. The expanded mission meant that Worden spent much of his time at North American Rockwell's facilities at Downey, California, where the command and service module (CSM) was being built. He undertook a different kind of geology training. Working with El-Baz, he studied maps and photographs of the craters he would pass over while orbiting alone in the CSM. As El-Baz listened and gave feedback, Worden learned how to describe lunar features in a way that would be useful to the scientists who would listen to his transmissions back on Earth. Worden found El-Baz to be an enjoyable and inspiring teacher. Worden usually accompanied his crewmates on their geology field trips, though he was often in an airplane overhead, describing features of the landscape as the plane simulated the speed at which the lunar landscape would pass below the CSM. The demands of the training strained both Worden's and Irwin's marriages; each sought Scott's advice, fearing a divorce might endanger their places on the mission as not projecting the image NASA wanted for the astronauts. Scott consulted Director of Flight Crew Operations Deke Slayton, their boss, who stated what was important was that the astronauts do their jobs. Although the Irwins overcame their marital difficulties, the Wordens divorced before the mission.
Apollo 15	Hardware	Hardware
Apollo 15	Spacecraft	Spacecraft thumb\|upright\|left\|alt=Area of spacecraft with lunar sensors\|Apollo 15 SM SIM bay Apollo 15 used command and service module CSM-112, which was given the call sign Endeavour, named after HMS Endeavour, and Lunar Module LM-10, call sign Falcon, named after the United States Air Force Academy mascot. Scott explained the choice of the name Endeavour on the grounds that its captain, James Cook, had commanded the first purely scientific sea voyage, and Apollo 15 was the first lunar landing mission on which there was a heavy emphasis on science. Apollo 15 took with it a small piece of wood from Cook's ship, while Falcon carried two falcon feathers to the Moon in recognition of the crew's service in the Air Force. Also part of the spacecraft were a Launch Escape System and a Spacecraft-Lunar Module Adapter, numbered SLA-19. Technicians at the Kennedy Space Center had some problems with the instruments in the service module's scientific instrument module (SIM) bay. Some instruments were late in arriving, and principal investigators or representatives of NASA contractors sought further testing or to make small changes. Mechanical problems came from the fact the instruments were designed to operate in space, but had to be tested on the surface of the Earth. As such, things like the 7.5 m (24 ft) booms for the mass and gamma ray spectrometers could be tested only using equipment that tried to mimic the space environment, and, in space, the mass spectrometer boom several times did not fully retract. On the Lunar Module, the fuel and oxidizer tanks were enlarged on both the descent and ascent stages, and the engine bell on the descent stage was extended. Batteries and solar cells were added for increased electrical power. In all this increased the weight of the Lunar Module to , heavier than previous models. If Apollo 15 had flown as an H mission, it would have been with CSM-111 and LM-9. That CSM was used by the Apollo–Soyuz Test Project in 1975, but the lunar module went unused and is now at the Kennedy Space Center Visitor Complex. Endeavour is on display at the National Museum of the United States Air Force at Wright-Patterson Air Force Base in Dayton, Ohio, following its transfer of ownership from NASA to the Smithsonian in December 1974.
Apollo 15	Launch vehicle	Launch vehicle The Saturn V that launched Apollo 15 was designated SA-510, the tenth flight-ready model of the rocket. As the payload of the rocket was greater, changes were made to the rocket and to its launch trajectory. It was launched in a more southerly direction (80–100 degrees azimuth) than previous missions, and the Earth parking orbit was lowered to . These two changes meant more could be launched. The propellant reserves were reduced and the number of retrorockets on the S-IC first stage (used to separate the spent first stage from the S-II second stage) reduced from eight to four. The four outboard engines of the S-IC would be burned longer and the center engine would also burn longer. Changes were also made to the S-II to dampen pogo oscillations. Once all major systems were installed in the SaturnV, it was moved from the Vehicle Assembly Building to the launch site, Launch Complex 39A. During late June and early July 1971, the rocket and Launch Umbilical Tower (LUT) were struck by lightning at least four times. There was no damage to the vehicle, and only minor damage to ground support equipment.
Apollo 15	Space suits	Space suits The Apollo 15 astronauts wore redesigned space suits. On all previous Apollo flights, including the non-lunar flights, the commander and lunar module pilot had worn suits with the life support, liquid cooling, and communications connections in two parallel rows of three. On Apollo 15, the new suits, dubbed the "A7LB", had the connectors situated in triangular pairs. This new arrangement, along with the relocation of the entry zipper (which went in an up-down motion on the old suits), to run diagonally from the right shoulder to the left hip, aided in suiting and unsuiting in the cramped confines of the spacecraft. It also allowed for a new waist joint, letting the astronauts bend completely over, and sit on the rover. Upgraded backpacks allowed for longer-duration moonwalks. As in all missions from and after Apollo 13, the commander's suit bore a red stripe on the helmet, arms and legs. Worden wore a suit similar to those worn by the Apollo 14 astronauts, but modified to interface with Apollo 15's equipment. Gear needed only for lunar surface EVAs, such as the liquid cooling garment, was not included with Worden's suit, as the only EVA he was expected to do was one to retrieve film cartridges from the SIM bay on the flight home.
Apollo 15	Lunar Roving Vehicle	Lunar Roving Vehicle thumb\|upright=1.49\|right\|alt=Astronaut works on the Moon at the lunar rover\|Irwin with the Lunar Roving Vehicle on the Moon. Mons Hadley is in the background. A vehicle that could operate on the surface of the Moon had been considered by NASA since the early 1960s. An early version was called MOLAB, which had a closed cabin and would have massed about ; some scaled-down prototypes were tested in Arizona. As it became clear NASA would not soon establish a lunar base, such a large vehicle seemed unnecessary. Still, a rover would enhance the J missions, which were to concentrate on science, though its mass was limited to about and it was not then clear that so light a vehicle could be useful. NASA did not decide to proceed with a rover until May 1969, as Apollo 10, the dress rehearsal for the Moon landing, made its way home from lunar orbit. Boeing received the contract for three rovers on a cost-plus basis; overruns (especially in the navigation system) meant the three vehicles eventually cost a total of $40 million. These cost overruns gained considerable media attention at a time of greater public weariness with the space program, when NASA's budget was being cut. The Lunar Roving Vehicle could be folded into a space 5 ft by 20 in (1.5 m by 0.5 m). Unloaded, it weighed 460 lb (209 kg) and when carrying two astronauts and their equipment, 1500 lb (700 kg). Each wheel was independently driven by a horsepower (200 W) electric motor. Although it could be driven by either astronaut, the commander always drove. Travelling at speeds up to 6to 8mph (10to 12km/h), astronauts for the first time could travel far afield from their lander and still have enough time to do some scientific experiments. The Apollo 15 rover bore a plaque, reading: "Man's First Wheels on the Moon, Delivered by Falcon, July 30, 1971". During pre-launch testing, the LRV was given additional bracing, lest it collapse if someone sat on it under Earth conditions.
Apollo 15	Particles and Fields Subsatellite	Particles and Fields Subsatellite thumb\|right\|alt=Illustration of satellite being deployed from a space vehicle\|Artist's conception of subsatellite deployment The Apollo 15 Particles and Fields Subsatellite (PFS-1) was a small satellite released into lunar orbit from the SIM bay just before the mission left orbit to return to Earth. Its main objectives were to study the plasma, particle, and magnetic field environment of the Moon and map the lunar gravity field. Specifically, it measured plasma and energetic particle intensities and vector magnetic fields, and facilitated tracking of the satellite velocity to high precision. A basic requirement was that the satellite acquire fields and particle data everywhere on the orbit around the Moon. As well as measuring magnetic fields, the satellite contained sensors to study the Moon's mass concentrations, or mascons. The satellite orbited the Moon and returned data from August 4, 1971, until January 1973, when, following multiple failures of the subsatellite's electronics, ground support was terminated. It is believed to have crashed into the Moon sometime thereafter.
Apollo 15	Mission highlights	Mission highlights
Apollo 15	Launch and outbound trip	Launch and outbound trip thumb\|right\|alt=Film of a rocket lifting off\|Apollo 15 launches on July 26, 1971 Apollo 15 was launched on July 26, 1971, at 9:34am EDT from the Kennedy Space Center at Merritt Island, Florida. The time of launch was at the very start of the two-hour, 37-minute launch window, which would allow Apollo 15 to arrive at the Moon with the proper lighting conditions at Hadley Rille; had the mission been postponed beyond another window on July 27, it could not have been rescheduled until late August. The astronauts had been awakened five and a quarter hours before launch by Slayton, and after breakfast and suiting up, had been taken to Pad 39A, launch site of all seven attempts at crewed lunar landing, and entered the spacecraft about three hours before launch. There were no unplanned delays in the countdown. At 000:11:36 into the mission, the S-IVB engine shut down, leaving Apollo 15 in its planned parking orbit in low Earth orbit. The mission remained there for 2hours and 40 minutes, allowing the crew (and Houston, via telemetry) to check the spacecraft's systems. At 002:50.02.6 into the mission, the S-IVB was restarted for trans-lunar injection (TLI), placing the craft on a path to the Moon. Before TLI, the craft had completed 1.5 orbits around the Earth. thumb\|left\|alt=Video showing the final stages of spacecraft docking with lunar module\|Astronaut Al Worden maneuvers the CSM to a docking with the Lunar Module Falcon The command and service module (CSM) and the Lunar Module remained attached to the nearly-exhausted S-IVB booster. Once trans-lunar injection had been achieved, placing the spacecraft on a trajectory towards the Moon, explosive cords separated the CSM from the booster as Worden operated the CSM's thrusters to push it away. Worden then maneuvered the CSM to dock with the LM (mounted on the end of the S-IVB), and the combined craft was then separated from the S-IVB by explosives. After Apollo 15 separated from the booster, the S-IVB maneuvered away, and, as planned, impacted the Moon about an hour after the crewed spacecraft entered lunar orbit, though due to an error the impact was away from the intended target. The booster's impact was detected by the seismometers left on the Moon by Apollo 12 and Apollo 14, providing useful scientific data. There was a malfunctioning light on the craft's service propulsion system (SPS); after considerable troubleshooting, the astronauts did a test burn of the system that also served as a midcourse correction. This occurred about 028:40:00 into the mission. Fearing that the light meant the SPS might unexpectedly fire, the astronauts avoided using the control bank with the faulty light, bringing it online only for major burns, and controlling it manually. After the mission returned, the malfunction proved to be caused by a tiny bit of wire trapped within the switch. thumb\|upright\|alt=Picture of Earth taken from space\|Image of Earth taken during the translunar coast After purging and renewing the LM's atmosphere to eliminate any contamination, the astronauts entered the LM about 34 hours into the mission, needing to check the condition of its equipment and move in items that would be required on the Moon. Much of this work was televised back to Earth, the camera operated by Worden. The crew discovered a broken outer cover on the Range/Range Rate tapemeter. This was a concern not only because an important piece of equipment, providing information on distance and rate of approach, might not work properly, but because bits of the glass cover were floating around Falcon interior. The tapemeter was supposed to be in a helium atmosphere, but due to the breakage, it was in the LM's oxygen atmosphere. Testing on the ground verified the tapemeter would still work properly, and the crew removed most of the glass using a vacuum cleaner and adhesive tape. As yet, there had been only minor problems, but at about 61:15:00 mission time (the evening of July 28 in Houston), Scott discovered a leak in the water system while preparing to chlorinate the water supply. The crew could not tell where it was coming from, and the issue had the potential to become serious. The experts in Houston found a solution, which was successfully implemented by the crew. The water was mopped up with towels, which were then put out to dry in the tunnel between the command module (CM) and Lunar Module—Scott stated it looked like someone's laundry. At 073:31:14 into the mission, a second midcourse correction, with less than a second of burn, was made. Although there were four opportunities to make midcourse corrections following TLI, only two were needed. Apollo 15 approached the Moon on July 29, and the lunar orbit insertion (LOI) burn had to be made using the SPS, on the far side of the Moon, out of radio contact with Earth. If no burn occurred, Apollo 15 would emerge from the lunar shadow and come back in radio contact faster than expected; the continued lack of communication allowed Mission Control to conclude that the burn had taken place. When contact resumed, Scott did not immediately give the particulars of the burn, but spoke admiringly of the beauty of the Moon, causing Alan Shepard, the Apollo 14 commander, who was awaiting a television interview, to grumble, "To hell with that shit, give us details of the burn." The 398.36-second burn took place at 078:31:46.7 into the mission at an altitude of above the Moon, and placed Apollo 15 in an elliptical lunar orbit of .
Apollo 15	Lunar orbit and landing	Lunar orbit and landing thumb\|upright=1.2\|alt=Control panel of lunar lander\|The interior of Falcon thumb\|upright=1.2\|The Apollo 15 command and service module in lunar orbit, photographed from Falcon On Apollo 11 and 12, the Lunar Module decoupled from the CSM and was piloted to a much lower orbit from which the lunar landing attempt commenced; to save fuel in an increasingly heavy lander, beginning with Apollo 14, the SPS in the service module made that burn, known as descent orbit insertion (DOI), with the lunar module still attached to the CSM. The initial orbit Apollo 15 was in had its apocynthion, or high point, over the landing site at Hadley; a burn at the opposite point in the orbit was performed, with the result that Hadley would now be under the craft's pericynthion, or low point. The DOI burn was performed at 082:39:49.09 and took 24.53 seconds; the result was an orbit with apocynthion of and pericynthion of . Overnight between July 29 and 30, as the crew rested, it became apparent to Mission Control that mass concentrations in the Moon were making Apollo 15's orbit increasingly elliptical—pericynthion was by the time the crew was awakened on July 30. This, and uncertainty as to the exact altitude of the landing site, made it desirable that the orbit be modified, or trimmed. Using the craft's RCS thrusters, this took place at 095:56:44.70, lasting 30.40 seconds, and raised the pericynthion to and the apocynthion to . As well as preparing the Lunar Module for its descent, the crew continued observations of the Moon (including of the landing site at Hadley) and provided television footage of the surface. Then, Scott and Irwin entered the Lunar Module in preparation for the landing attempt. Undocking was planned for 100:13:56, over the far side of the Moon, but nothing happened when separation was attempted. After analyzing the problem, the crew and Houston decided the probe instrumentation umbilical was likely loose or disconnected; Worden went into the tunnel connecting the command and lunar modules and determined this was so, seating it more firmly. With the problem resolved, Falcon separated from Endeavour at 100:39:16.2, about 25 minutes late, at an altitude of . Worden in Endeavour executed a SPS burn at 101:38:58.98 to send Endeavour to an orbit of by in preparation for his scientific work. Aboard Falcon, Scott and Irwin prepared for powered descent initiation (PDI), the burn that was to place them on the lunar surface, and, after Mission Control gave them permission, they initiated PDI at 104:30:09.4 at an altitude of , slightly higher than planned. During the first part of the descent, Falcon was aligned so the astronauts were on their backs and thus could not see the lunar surface below them, but after the craft made a pitchover maneuver, they were upright and could see the surface in front of them. Scott, who as commander performed the landing, was confronted with a landscape that did not at first seem to resemble what he had seen during simulations. Part of this was due to an error in the landing path of some , of which CAPCOM Ed Mitchell informed the crew prior to pitchover; part because the craters Scott had relied on in the simulator were difficult to make out under lunar conditions, and he initially could not see Hadley Rille. He concluded that they were likely to overshoot the planned landing site, and, once he could see the rille, started maneuvering the vehicle to move the computer's landing target back towards the planned spot, and looked for a relatively smooth place to land. thumb\|upright=1.2\|alt=Film showing the lunar surface as the lander descends to it\|Apollo 15 landing on the Moon at Hadley, seen from the perspective of the Lunar Module Pilot. Starts at about . Below about , Scott could see nothing of the surface because of the quantities of lunar dust being displaced by Falcon exhaust. Falcon had a larger engine bell than previous LMs, in part to accommodate a heavier load, and the importance of shutting down the engine at initial contact rather than risk "blowback", the exhaust reflecting off the lunar surface and going back into the engine (possibly causing an explosion) had been impressed on the astronauts by mission planners. Thus, when Irwin called "Contact", indicating that one of the probes on the landing leg extensions had touched the surface, Scott immediately shut off the engine, letting the lander fall the remaining distance to the surface. Already moving downward at about per second, Falcon dropped from a height of . Scott's speed resulted in what was likely the hardest lunar landing of any of the crewed missions, at about per second, causing a startled Irwin to yell "Bam!" Scott had landed Falcon on the rim of a small crater he could not see, and the lander settled back at an angle of 6.9 degrees and to the left of 8.6 degrees. Irwin described it in his autobiography as the hardest landing he had ever been in, and he feared that the craft would keep tipping over, forcing an immediate abort. Falcon landed at 104:42:29.3 (22:16:29 GMT on July 30), with approximately 103 seconds of fuel remaining, about from the planned landing site. After Irwin's exclamation, Scott reported, "Okay, Houston. The Falcon is on the Plain at Hadley." Once within the planned landing zone, the increased mobility provided by the Lunar Roving Vehicle made unnecessary any further maneuvering.
Apollo 15	Lunar surface	Lunar surface
Apollo 15	Stand-up EVA and first EVA	Stand-up EVA and first EVA With Falcon due to remain on the lunar surface for almost three days, Scott deemed it important to maintain the circadian rhythm they were used to, and as they had landed in the late afternoon, Houston time, the two astronauts were to sleep before going onto the surface. But the time schedule allowed Scott to open the lander's top hatch (usually used for docking) and spend a half hour looking at their surroundings, describing them, and taking photographs. Lee Silver had taught him the importance of going to a high place to survey a new field site, and the top hatch served that purpose. Deke Slayton and other managers were initially opposed due to the oxygen that would be lost, but Scott got his way. During the only stand-up extravehicular activity (EVA) ever performed through the LM's top hatch on the lunar surface, Scott was able to make plans for the following day's EVA. He offered Irwin a chance to look out as well, but this would have required rearranging the umbilicals connecting Irwin to Falcon life support system, and he declined. After repressurizing the spacecraft, Scott and Irwin removed their space suits for sleep, becoming the first astronauts to doff their suits while on the Moon. thumb\|alt=Film taken aboard the lunar rover\|Aboard the Lunar Roving Vehicle Throughout the sleep period Mission Control in Houston monitored a slow but steady oxygen loss. Scott and Irwin eventually were awakened an hour early, and the source of the problem was found to be an open valve on the urine transfer device. In post-mission debriefing, Scott recommended that future crews be woken at once under similar circumstances. After the problem was solved, the crew began preparation for the first Moon walk. After donning their suits and depressurizing the cabin, Scott and Irwin began their first full EVA, becoming the seventh and eighth humans, respectively, to walk on the Moon. They began deploying the lunar rover, stored folded up in a compartment of Falcon descent stage, but this proved troublesome due to the slant of the lander. The experts in Houston suggested lifting the front end of the rover as the astronauts pulled it out, and this worked. Scott began a system checkout. One of the batteries gave a zero voltage reading, but this was only an instrumentation problem. A greater concern was that the front wheel steering would not work. However, the rear wheel steering was sufficient to maneuver the vehicle. Completing his checkout, Scott said "Okay. Out of detent; we're moving", maneuvering the rover away from Falcon in mid-sentence. These were the first words uttered by a human while driving a vehicle on the Moon. The rover carried a television camera, controlled remotely from Houston by NASA's Ed Fendell. The resolution was not high compared to the still photographs that would be taken, but the camera allowed the geologists on Earth to indirectly participate in Scott and Irwin's activities. The rille was not visible from the landing site, but as Scott and Irwin drove over the rolling terrain, it came into view. They were able to see Elbow crater, and they began to drive in that direction. Reaching Elbow, a known location, allowed Mission Control to backtrack and get closer to pinpointing the location of the lander. The astronauts took samples there, and then drove to another crater on the flank of Mons Hadley Delta, where they took more. After concluding this stop, they returned to the lander to drop off their samples and prepare to set up the Apollo Lunar Surface Experiments Package (ALSEP), the scientific instruments that would remain when they left. Scott had difficulty drilling the holes required for the heat flow experiment, and the work was not completed when they had to return to the lander. The first EVA lasted 6hours and 32 minutes.
Apollo 15	Second and third EVAs	Second and third EVAs thumb\|right\|alt=A white rock, placed in a laboratory setting\|The Genesis Rock The rover's front steering, inoperative during the first EVA, worked during the second and third ones. The target of the second EVA, on August 1, was the slope of Mons Hadley Delta, where the pair sampled boulders and craters along the Apennine Front. They spent an hour at Spur crater, during which the astronauts collected a sample dubbed the Genesis Rock. This rock, an anorthosite, is believed to be part of the early lunar crust—the hope of finding such a specimen had been one reason the Hadley area had been chosen. Once back at the landing site, Scott continued to try to drill holes for experiments at the ALSEP site, with which he had struggled the day before. After conducting soil-mechanics experiments and raising the U.S. flag, Scott and Irwin returned to the LM. EVA2 lasted 7hours and 12 minutes. Although Scott had eventually been successful at drilling the holes, he and Irwin had been unable to retrieve a core sample, and this was an early order of business during EVA 3, their third and final moonwalk. Time that could have been devoted to geology ticked away as Scott and Irwin attempted to pull it out. Once it had been retrieved, more time passed as they attempted to break the core into pieces for transport to Earth. Hampered by an incorrectly mounted vise on the rover, they eventually gave up on this—the core would be transported home with one segment longer than planned. Scott wondered if the core was worth the amount of time and effort invested, and the CAPCOM, Joe Allen, assured him it was. The core proved one of the most important items brought back from the Moon, revealing much about its history, but the expended time meant the planned visit to a group of hills known as the North Complex had to be scrubbed. Instead, the crew again ventured to the edge of Hadley Rille, this time to the northwest of the immediate landing site. thumb\|alt=Video of an astronaut dropping a hammer and a feather while on the Moon\|David Scott's hammer and feather experiment Once the astronauts were beside the LM, Scott used a kit provided by the Postal Service to cancel a first day cover of two stamps being issued on August 2, the current date. Scott then performed an experiment in view of the television camera, using a falcon feather and hammer to demonstrate Galileo's theory that all objects in a given gravity field fall at the same rate, regardless of mass, in the absence of aerodynamic drag. He dropped the hammer and feather at the same time; because of the negligible lunar atmosphere, there was no drag on the feather, which hit the ground at the same time as the hammer. This was Joe Allen's idea (he also served as CAPCOM during it) and was part of an effort to find a memorable popular science experiment to do on the Moon along the lines of Shepard's hitting of golf balls. The feather was most likely from a female gyrfalcon (a type of falcon), a mascot at the United States Air Force Academy. thumb\|left\|alt=A small aluminum statue and a plaque on the lunar surface\|The Fallen Astronaut memorial, near Hadley Rille, Moon Scott then drove the rover to a position away from the LM, where the television camera could be used to observe the lunar liftoff. Near the rover, he left a small aluminum statuette called Fallen Astronaut, along with a plaque bearing the names of 14 known American astronauts and Soviet cosmonauts who had died in the furtherance of space exploration. The memorial was left while the television camera was turned away; he told Mission Control he was doing some cleanup activities around the rover. Scott disclosed the memorial in a post-flight news conference. He also placed a Bible on the control panel of the rover before leaving it for the last time to enter the LM. The EVA lasted 4 hours, 49 minutes and 50 seconds. In total, the two astronauts spent 18 hours outside the LM and collected approximately of lunar samples.
Apollo 15	Command module activities	Command module activities After the departure of Falcon, Worden in Endeavour executed a burn to take the CSM to a higher orbit. While Falcon was on the Moon, the mission effectively split, Worden and the CSM being assigned their own CAPCOM and flight support team. thumb\|upright=1.3\|left\|alt=A spacecraft seen with the Moon in background\|Endeavour, with the SIM bay exposed, as seen from the Lunar Module Falcon Worden got busy with the tasks that were to occupy him for much of the time he spent in space alone: photography and operating the instruments in the SIM bay. The door to the SIM bay had been explosively jettisoned during the translunar coast. Filling previously unused space in the service module, the SIM bay contained a gamma-ray spectrometer, mounted on the end of a boom, an X-ray spectrometer and a laser altimeter, which failed part way through the mission. Two cameras, a stellar camera and a metric camera, together comprised the mapping camera, which was complemented by a panoramic camera, derived from spy technology. The altimeter and cameras permitted the exact time and location from which pictures were taken to be determined. Also present were an alpha particle spectrometer, which could be used to detect evidence of lunar volcanism, and a mass spectrometer, also on a boom in the hope it would be unaffected by contamination from the ship. The boom would prove troublesome, as Worden would not always be able to get it to retract. thumb\|alt=Part of the lunar surface\|The landing area is shown in an image taken by the mapping camera Endeavour was slated to pass over the landing site at the moment of planned landing, but Worden could not see Falcon and did not spot it until a subsequent orbit. He also exercised to avoid muscle atrophy, and Houston kept him up to date on Scott and Irwin's activities on the lunar surface. The panoramic camera did not operate perfectly, but provided enough images that no special adjustment was made. Worden took many photographs through the command module's windows, often with shots taken at regular intervals. His task was complicated by the lack of a working mission timer in the Lower Equipment Bay of the command module, as its circuit breaker had popped en route to the Moon. Worden's observations and photographs would inform the decision to send Apollo 17 to Taurus-Littrow to search for evidence of volcanic activity. There was a communications blackout when the CSM passed over the far side of the Moon from Earth; Worden greeted each resumption of contact with the words, "Hello, Earth. Greetings from Endeavour", expressed in different languages. Worden and El-Baz had come up with the idea, and the geology instructor had aided the astronaut in accumulating translations. Results from the SIM bay experiments would include the conclusion, from data gathered by the X-ray spectrometer, that there was greater fluorescent X-ray flux than anticipated, and that the lunar highlands were richer in aluminum than were the mares. Endeavour was in a more inclined orbit than previous crewed missions, and Worden saw features that were not known previously, supplementing photographs with thorough descriptions. By the time Scott and Irwin were ready to take off from the lunar surface and return to Endeavour, the CSM's orbit had drifted due to the rotation of the Moon, and a plane change burn was required to ensure that the CSM's orbit would be in the same plane as that of the LM once it took off from the Moon. Worden accomplished the 18-second burn with the SPS.
Apollo 15	Return to Earth	Return to Earth thumb \|alt=Video showing the lunar lander taking off\|The liftoff from the Moon as seen by the TV camera on the lunar rover Falcon lifted off the Moon at 17:11:22 GMT on August2 after 66 hours and 55 minutes on the lunar surface. Docking with the CSM took place just under two hours later. After the astronauts transferred samples and other items from the LM to the CSM, the LM was sealed off, jettisoned, and intentionally crashed into the lunar surface, an impact registered by the seismometers left by Apollo 12, 14 and 15. The jettison proved difficult because of problems getting airtight seals, requiring a delay in discarding the LM. After the jettison, Slayton came on the loop to recommend the astronauts take sleeping pills, or at least that Scott and Irwin do so. Scott as mission commander refused to allow it, feeling there was no need. During the EVAs, the doctors had noticed irregularities in both Scott's and Irwin's heartbeats, but the crew were not informed during the flight. Irwin had heart problems after retiring as an astronaut and died in 1991 of a heart attack; Scott felt that he as commander should have been informed of the biomedical readings. NASA doctors at the time theorized the heart readings were due to potassium deficiency, due to their hard work on the surface and inadequate resupply through liquids. thumb\|left\|alt=Video of a man working outside the spacecraft\|Worden's deep space EVA The crew spent the next two days working on orbital science experiments, including more observations of the Moon from orbit and releasing the subsatellite. Endeavour departed lunar orbit with another burn of the SPS engine of 2minutes 21 seconds at 21:22:45 GMT on August4. The next day, during the return to Earth, Worden performed a 39-minute EVA to retrieve film cassettes from the service module's scientific instrument module (SIM) bay, with assistance from Irwin who remained at the command module's hatch. At approximately 171,000 nautical miles (197,000 mi; 317,000 km) from Earth, it was the first "deep space" EVA in history, performed at great distance from any planetary body. As of , it remains one of only three such EVAs, all performed during Apollo's J missions under similar circumstances. Later that day, the crew set a record for the longest Apollo flight to that point. On approach to Earth on August7, the service module was jettisoned, and the command module reentered the Earth's atmosphere. Although one of the three parachutes on the CM failed after deploying, likely due to damage as the spacecraft vented fuel, only two were required for a safe landing (one extra for redundancy). Upon landing in the North Pacific Ocean, the CM and crew were recovered and taken aboard the recovery ship, , after a mission lasting 12 days, 7hours, 11 minutes and 53 seconds.
Apollo 15	Assessment	Assessment The mission objectives for Apollo 15 were to "perform selenological inspection, survey, and sampling of materials and surface features in a pre-selected area of the Hadley–Apennine region. Emplace and activate surface experiments. Evaluate the capability of the Apollo equipment to provide extended lunar surface stay time, increased extravehicular operations, and surface mobility. [and] Conduct inflight experiments and photographic tasks from lunar orbit." It achieved all those objectives. The mission also completed a long list of other tasks, including experiments. One of the photographic objectives, to obtain images of the gegenschein from lunar orbit, was not completed, as the camera was not pointed at the proper spot in the sky. According to the conclusions in the Apollo 15 Mission Report, the journey "was the fourth lunar landing and resulted in the collection of a wealth of scientific information. The Apollo system, in addition to providing a means of transportation, excelled as an operational scientific facility." Apollo 15 saw an increase in public interest in the Apollo program, in part due to fascination with the LRV, as well as the attractiveness of the Hadley Rille site and the increased television coverage. According to David Woods in the Apollo Lunar Flight Journal,
Apollo 15	Controversies	Controversies thumb\|alt=Envelope with mission patch logo, three stamps and two postmarks\|A "Sieger cover" Despite the successful mission, the careers of the crew were tarnished by a deal they had made before the flight to carry postal covers to the Moon in exchange for about $7,000 each, which they planned to set aside for their children. Walter Eiermann, who had many professional and social contacts with NASA employees and the astronaut corps, served as intermediary between the astronauts and a West German stamp dealer, Hermann Sieger, and Scott carried about 400 covers onto the spacecraft; they were subsequently transferred into Falcon and remained inside the lander during the astronauts' activities on the surface of the Moon. After the return to Earth, 100 of the covers were given to Eiermann, who passed them on to Sieger, receiving a commission. No permission had been received from Slayton to carry the covers, as required. The 100 covers were put on sale to Sieger's customers in late 1971 at a price of about $1,500 each. After receiving the agreed payments, the astronauts returned them, and accepted no compensation. In April 1972, Slayton learned that unauthorized covers had been carried, and removed the three as the backup crew for Apollo 17. The matter became public in June 1972 and the three astronauts were reprimanded for poor judgment; none ever flew in space again. During the investigation, the astronauts had surrendered those covers still in their possession; after Worden filed suit, they were returned in 1983, something Slate magazine deemed an exoneration. Another controversy arose later, this time surrounding the Fallen Astronaut statuette that Scott had left on the Moon. Before the mission, Scott had made a verbal agreement with Belgian artist Paul Van Hoeydonck to sculpt the statuette. Scott's intent, in keeping with NASA's strict policy against commercial exploitation of the US government's space program, was for a simple memorial with a minimum of publicity, keeping the artist anonymous, no commercial replicas being made except for a single copy for public exhibit at the National Air and Space Museum commissioned after the sculpture's public disclosure during the post-flight press conference. Van Hoeydonck claims to have had a different understanding of the agreement, by which he would have received recognition as the creator of a tribute to human space exploration, with rights to sell replicas to the public. Under pressure from NASA, Van Hoeydonck canceled a plan to publicly sell 950 signed copies. In 2021, Scott published a document entitled "Memorandum for the Record", in which he stated that the figurine left on the Moon was designed and fabricated by NASA personnel. While testifying before a Senate committee in 1972, he had stated that the figurine had been made and provided by Van Hoeydonck at Scott's request. During those congressional hearings into the postal covers and Fallen Astronaut matters, two Bulova timepieces taken on the mission by Scott were also matters of controversy. Before the mission, Scott had been introduced to Bulova's representative, General James McCormack by Apollo 8 commander Frank Borman. Bulova had been seeking to have its timepieces taken on Apollo missions, but after evaluation, NASA had selected Omega watches instead. Scott brought the Bulova timepieces on the mission, without disclosing them to Slayton. During Scott's second EVA, the crystal on his NASA standard issue Omega Speedmaster watch popped off, and, during the third EVA, he used a Bulova watch. The Bulova Chronograph Model #88510/01 that Scott wore on the lunar surface was a prototype, given to him by the Bulova Company, and it is the only privately owned watch to have been worn while walking on the lunar surface. There are images of him wearing this watch, when he saluted the American flag on the Moon, with the Hadley Delta expanse in the background. In 2015, the watch sold for $1.625 million, which makes it one of the most expensive astronaut-owned artifact ever sold at auction and one of the most expensive watches sold at auction.
Apollo 15	Mission insignia	Mission insignia thumb\|right\|The Chevrolet Corvettes driven by Scott (right) and Worden during the training for Apollo 15, photographed in 2019 The Apollo 15 mission patch carries Air Force motifs, a nod to the crew's service there, just as the Apollo 12 all-Navy crew's patch had featured a sailing ship. The circular patch features stylized red, white and blue birds flying over Hadley Rille. Immediately behind the birds, a line of craters forms the Roman numeral XV. The Roman numerals were hidden in emphasized outlines of some craters after NASA insisted that the mission number be displayed in Arabic numerals. The artwork is circled in red, with a white band giving the mission and crew names and a blue border. Scott contacted fashion designer Emilio Pucci to design the patch, who came up with the basic idea of the three-bird motif on a square patch. thumb\|left\|alt=Both sides of a silver "Robbins" medallion with the mission logo and dates of travel\|Apollo 15 space-flown silver Robbins medallion The crew changed the shape to round and the colors from blues and greens to a patriotic red, white and blue. Worden stated that each bird also represented an astronaut, white being his own color (and as Command Module Pilot, uppermost), Scott being the blue bird and Irwin the red. The colors matched Chevrolet Corvettes leased by the astronauts at KSC;Worden & French 2011, pp. 144–145 a Florida car dealer had, since the time of Project Mercury, been leasing Chevrolets to astronauts for $1 and later selling them to the public. The astronauts were photographed with the cars and the training LRV for the June 11, 1971, edition of Life magazine.
Apollo 15	Visibility from space	Visibility from space The halo area of the Apollo 15 landing site, created by the LM's exhaust plume, was observed by a camera aboard the Japanese lunar orbiter SELENE and confirmed by comparative analysis of photographs in May 2008. This corresponds well to photographs taken from the Apollo 15 command module showing a change in surface reflectivity due to the plume, and was the first visible trace of crewed landings on the Moon seen from space since the close of the Apollo program.
Apollo 15	Gallery	Gallery
Apollo 15	Still images	Still images
Apollo 15	Multimedia	Multimedia
Apollo 15	See also	See also List of artificial objects on the Moon List of missions to the Moon List of spacewalks and moonwalks 1965–1999
Apollo 15	Notes	Notes
Apollo 15	References	References
Apollo 15	Apollo Lunar Flight Journal	Apollo Lunar Flight Journal
Apollo 15	Apollo Lunar Surface Journal	Apollo Lunar Surface Journal
Apollo 15	Bibliography	Bibliography
Apollo 15	External links	External links Apollo 15 Preliminary Science Report (1972) by the Manned Spacecraft Center Apollo 15 Traverses, 41B4S4(25), Lunar Photomap at Lunar and Planetary Institute 1975 summary report by NASA 1972 NASA press releases at collectSPACE Moonport: A History of Apollo Launch Facilities and Operations, a 1978 book published by NASA Part 1 and part 2 of Apollo 15: In the Mountains of the Moon, a NASA documentary film on the Apollo 15 mission, at the Internet Archive 2011 podcast interview with AstrotalkUK 2016 interview with Worden at Medium Category:James Irwin Category:David Scott Category:Alfred Worden Category:Articles containing video clips Category:Apollo program missions Category:Extravehicular activity Category:LQ12 quadrangle Category:Lunar rovers Category:Crewed missions to the Moon Category:Sample return missions Category:Soft landings on the Moon Category:Spacecraft which reentered in 1971 Category:Spacecraft launched in 1971 Category:July 1971 Category:August 1971 Category:Spacecraft launched by Saturn rockets Category:1971 on the Moon Category:Successful space missions
Apollo 15	Table of Content	Short description, Background, Crew and key Mission Control personnel, Crew, Mission Control, Planning and training, Hardware, Spacecraft, Launch vehicle, Space suits, Lunar Roving Vehicle, Particles and Fields Subsatellite, Mission highlights, Launch and outbound trip, Lunar orbit and landing, Lunar surface, Stand-up EVA and first EVA, Second and third EVAs, Command module activities, Return to Earth, Assessment, Controversies, Mission insignia, Visibility from space, Gallery, Still images, Multimedia, See also, Notes, References, Apollo Lunar Flight Journal, Apollo Lunar Surface Journal, Bibliography, External links
Apollo 16	Short description	Apollo 16 (April 1627, 1972) was the tenth crewed mission in the United States Apollo space program, administered by NASA, and the fifth and penultimate to land on the Moon. It was the second of Apollo's "J missions", with an extended stay on the lunar surface, a focus on science, and the use of the Lunar Roving Vehicle (LRV). The landing and exploration were in the Descartes Highlands, a site chosen because some scientists expected it to be an area formed by volcanic action, though this proved not to be the case. The mission was crewed by Commander John Young, Lunar Module Pilot Charles Duke and Command Module Pilot Ken Mattingly. Launched from the Kennedy Space Center in Florida on April 16, 1972, Apollo 16 experienced a number of minor glitches en route to the Moon. These culminated with a problem with the spacecraft's main engine that resulted in a six-hour delay in the Moon landing as NASA managers contemplated having the astronauts abort the mission and return to Earth, before deciding the problem could be overcome. Although they permitted the lunar landing, NASA had the astronauts return from the mission one day earlier than planned. After flying the Lunar Module to the Moon's surface on April 21, Young and Duke spent 71 hours—just under three days—on the lunar surface, during which they conducted three extravehicular activities or moonwalks, totaling 20 hours and 14 minutes. The pair drove the lunar rover, the second used on the Moon, for . On the surface, Young and Duke collected of lunar samples for return to Earth, including Big Muley, the largest Moon rock collected during the Apollo missions. During this time Mattingly orbited the Moon in the command and service module (CSM), taking photos and operating scientific instruments. Mattingly, in the command module, spent 126 hours and 64 revolutions in lunar orbit. After Young and Duke rejoined Mattingly in lunar orbit, the crew released a subsatellite from the service module (SM). During the return trip to Earth, Mattingly performed a one-hour spacewalk to retrieve several film cassettes from the exterior of the service module. Apollo 16 returned safely to Earth on April 27, 1972.
Apollo 16	Crew and key Mission Control personnel	Crew and key Mission Control personnel John Young, the mission commander, was 41 years old and a captain in the Navy at the time of Apollo 16. Becoming an astronaut in 1962 as part of the second group to be selected by NASA, he flew in Gemini 3 with Gus Grissom in 1965, becoming the first American not of the Mercury Seven to fly in space. He thereafter flew in Gemini 10 (1966) with Michael Collins and as command module pilot of Apollo 10 (1969). With Apollo 16, he became the second American, after Jim Lovell, to fly in space four times. Thomas Kenneth "Ken" Mattingly, the command module pilot, was 36 years old and a lieutenant commander in the Navy at the time of Apollo 16. Mattingly had been selected in NASA's fifth group of astronauts in 1966. He was a member of the support crew for Apollo 8 and Apollo 9. Mattingly then undertook parallel training with Apollo 11's backup CMP, William Anders, who had announced his resignation from NASA effective at the end of July 1969 and would thus be unavailable if the first lunar landing mission was postponed. Had Anders left NASA before Apollo 11 flew, Mattingly would have taken his place on the backup crew. Mattingly had originally been assigned to the prime crew of Apollo 13, but was exposed to rubella through Charles Duke, at that time with Young on Apollo 13's backup crew; Duke had caught it from one of his children. Mattingly never contracted the illness, but three days before launch was removed from the crew and replaced by his backup, Jack Swigert. Duke, also a Group 5 astronaut and a space rookie, had served on the support crew of Apollo 10 and was a capsule communicator (CAPCOM) for Apollo 11. A lieutenant colonel in the Air Force, Duke was 36 years old at the time of Apollo 16, which made him the youngest of the twelve astronauts who walked on the Moon during Apollo as of the time of the mission. All three men were announced as the prime crew of Apollo 16 on March 3, 1971. Apollo 16's backup crew consisted of Fred W. Haise Jr. (commander, who had flown on Apollo 13), Stuart A. Roosa (CMP, who had flown on Apollo 14) and Edgar D. Mitchell (LMP, also Apollo 14). Although not officially announced, Director of Flight Crew Operations Deke Slayton, the astronauts' supervisor, had originally planned to have a backup crew of Haise as commander, William R. Pogue (CMP) and Gerald P. Carr (LMP), who were targeted for the prime crew assignment on Apollo 19. However, after the cancellations of Apollos 18 and 19 were announced in September 1970, it made more sense to use astronauts who had already flown lunar missions as backups, rather than training others on what would likely be a dead-end assignment. Subsequently, Roosa and Mitchell were assigned to the backup crew, while Pogue and Carr were reassigned to the Skylab program where they flew on Skylab 4. For projects Mercury and Gemini, a prime and a backup crew had been designated, but for Apollo, a third group of astronauts, known as the support crew, was also designated. Slayton created the support crews early in the Apollo Program on the advice of Apollo crew commander James McDivitt, who would lead Apollo 9. McDivitt believed that, with preparation going on in facilities across the U.S., meetings that needed a member of the flight crew would be missed. Support crew members were to assist as directed by the mission commander. Usually low in seniority, they assembled the mission's rules, flight plan, and checklists, and kept them updated. For Apollo 16, they were: Anthony W. England, Karl G. Henize, Henry W. Hartsfield Jr., Robert F. Overmyer and Donald H. Peterson. Flight directors were Pete Frank and Philip Shaffer, first shift, Gene Kranz and Donald R. Puddy, second shift, and Gerry Griffin, Neil B. Hutchinson and Charles R. Lewis, third shift. Flight directors during Apollo had a one-sentence job description: "The flight director may take any actions necessary for crew safety and mission success." CAPCOMs were Haise, Roosa, Mitchell, James B. Irwin, England, Peterson, Hartsfield, and C. Gordon Fullerton.
Apollo 16	Mission insignia and call signs	Mission insignia and call signs thumb\|Apollo 16 space-flown silver Robbins medallion The insignia of Apollo 16 is dominated by a rendering of an American eagle and a red, white and blue shield, representing the people of the United States, over a gray background representing the lunar surface. Overlaying the shield is a gold NASA vector, orbiting the Moon. On its gold-outlined blue border, there are 16 stars, representing the mission number, and the names of the crew members: Young, Mattingly, Duke. The insignia was designed from ideas originally submitted by the crew of the mission, by Barbara Matelski of the graphics shop at the Manned Spacecraft Center in Houston. Young and Duke chose "Orion" for the Lunar Module's call sign, while Mattingly chose "Casper" for the command and service module. According to Duke, he and Young chose "Orion" for the LM because they wanted something connected with the stars. Orion is one of the brightest constellations as seen from Earth, and one visible to the astronauts throughout their journey. Duke also stated, "it is a prominent constellation and easy to pronounce and transmit to Mission Control". Mattingly said he chose "Casper", evoking Casper the Friendly Ghost, because "there are enough serious things in this flight, so I picked a non-serious name."
Apollo 16	Planning and training	Planning and training
Apollo 16	Landing site selection	Landing site selection Apollo 16 was the second of Apollo's J missions, featuring the use of the Lunar Roving Vehicle, increased scientific capability, and three-day lunar surface stays. As Apollo 16 was the penultimate mission in the Apollo program and there was no major new hardware or procedures to test on the lunar surface, the last two missions (the other being Apollo 17) presented opportunities for astronauts to clear up some of the uncertainties in understanding the Moon's characteristics. Scientists sought information on the Moon's early history, which might be obtained from its ancient surface features, the lunar highlands. Previous Apollo expeditions, including Apollo 14 and Apollo 15, had obtained samples of pre-mare lunar material, likely thrown from the highlands by meteorite impacts. These were dated from before lava began to upwell from the Moon's interior and flood the low areas and basins. Nevertheless, no Apollo mission had actually visited the lunar highlands. Apollo 14 had visited and sampled a ridge of material ejected by the impact that created the Mare Imbrium impact basin. Likewise, Apollo 15 had also sampled material in the region of Imbrium, visiting the basin's edge. Because the Apollo 14 and Apollo 15 landing sites were closely associated with the Imbrium basin, there was still the chance that different geologic processes were prevalent in areas of the lunar highlands far from Mare Imbrium. Scientist Dan Milton, studying photographs of the highlands from Lunar Orbiter photographs, saw an area in the Descartes region of the Moon with unusually high albedo that he theorized might be due to volcanic rock; his theory quickly gained wide support. Several members of the scientific community noted that the central lunar highlands resembled regions on Earth that were created by volcanism processes and hypothesized the same might be true on the Moon. They hoped scientific output from the Apollo 16 mission would provide an answer. Some scientists advocated for a landing near the large crater, Tycho, but its distance from the lunar equator and the fact that the Lunar Module would have to approach over very rough terrain ruled it out. thumb\|left\|300px\|Location of the Apollo 16 landing site The Ad Hoc Apollo Site Evaluation Committee met in April and May 1971 to decide the Apollo 16 and 17 landing sites; it was chaired by Noel Hinners of Bellcomm. There was consensus the final landing sites should be in the lunar highlands, and among the sites considered for Apollo 16 were the Descartes Highlands region west of Mare Nectaris and the crater Alphonsus. The considerable distance between the Descartes site and previous Apollo landing sites would also be beneficial for the network of seismometers, deployed on each landing mission beginning with Apollo 12. At Alphonsus, three scientific objectives were determined to be of primary interest and paramount importance: the possibility of old, pre-Imbrium impact material from within the crater's wall, the composition of the crater's interior and the possibility of past volcanic activity on the floor of the crater at several smaller "dark halo" craters. Geologists feared, however, that samples obtained from the crater might have been contaminated by the Imbrium impact, thus preventing Apollo 16 from obtaining samples of pre-Imbrium material. There also remained the distinct possibility that this objective would have already been satisfied by the Apollo 14 and Apollo 15 missions, as the Apollo 14 samples had not yet been completely analyzed and samples from Apollo 15 had not yet been obtained. On June 3, 1971, the site selection committee decided to target the Apollo 16 mission for the Descartes site. Following the decision, the Alphonsus site was considered the most likely candidate for Apollo 17, but was eventually rejected. With the assistance of orbital photography obtained on the Apollo 14 mission, the Descartes site was determined to be safe enough for a crewed landing. The specific landing site was between two young impact craters, North Ray and South Ray craters – in diameter, respectively – which provided "natural drill holes" which penetrated through the lunar regolith at the site, thus leaving exposed bedrock that could be sampled by the crew. After the selection, mission planners made the Descartes and Cayley formations, two geologic units of the lunar highlands, the primary sampling interest of the mission. It was these formations that the scientific community widely suspected were formed by lunar volcanism, but this hypothesis was proven incorrect by the composition of lunar samples from the mission.
Apollo 16	Training	Training thumb\|right\|John Young and Charles Duke training at the Rio Grande Gorge in New Mexico In addition to the usual Apollo spacecraft training, Young and Duke, along with backup commander Fred Haise, underwent an extensive geological training program that included several field trips to introduce them to concepts and techniques they would use in analyzing features and collecting samples on the lunar surface. During these trips, they visited and provided scientific descriptions of geologic features they were likely to encounter. The backup LMP, Mitchell, was unavailable during the early part of the training, occupied with tasks relating to Apollo 14, but by September 1971 had joined the geology field trips. Before that, Tony England (a member of the support crew and the lunar EVA CAPCOM) or one of the geologist trainers would train alongside Haise on geology field trips. Since Descartes was believed to be volcanic, a good deal of this training was geared towards volcanic rocks and features, but field trips were made to sites featuring other sorts of rock. As Young later commented, the non-volcanic training proved more useful, given that Descartes did not prove to be volcanic. In July 1971, they visited Sudbury, Ontario, Canada, for geology training exercises, the first time U.S. astronauts trained in Canada. The Apollo 14 landing crew had visited a site in West Germany; geologist Don Wilhelms related that unspecified incidents there had caused Slayton to rule out further European training trips. Geologists chose Sudbury because of a wide crater created about 1.8 billion years ago by a large meteorite. The Sudbury Basin shows evidence of shatter cone geology, familiarizing the Apollo crew with geologic evidence of a meteorite impact. During the training exercises the astronauts did not wear space suits, but carried radio equipment to converse with each other and England, practicing procedures they would use on the lunar surface. By the end of the training, the field trips had become major exercises, involving up to eight astronauts and dozens of support personnel, attracting coverage from the media. For the exercise at the Nevada Test Site, where the massive craters left by nuclear explosions simulated the large craters to be found on the Moon, all participants had to have security clearance and a listed next-of-kin, and an overflight by CMP Mattingly required special permission. thumb\|upright=1.4\|left\|Young (right) and Duke training to drive the Lunar Roving Vehicle In addition to the field geology training, Young and Duke also trained to use their EVA space suits, adapt to the reduced lunar gravity, collect samples, and drive the Lunar Roving Vehicle. The fact that they had been backups for Apollo 13, planned to be a landing mission, meant that they could spend about 40 percent of their time training for their surface operations. They also received survival training and prepared for technical aspects of the mission. The astronauts spent much time studying the lunar samples brought back by earlier missions, learning about the instruments to be carried on the mission, and hearing what the principal investigators in charge of those instruments expected to learn from Apollo 16. This training helped Young and Duke, while on the Moon, quickly realize that the expected volcanic rocks were not there, even though the geologists in Mission Control initially did not believe them. Much of the training—according to Young, 350 hours—was conducted with the crew wearing space suits, something that Young deemed vital, allowing the astronauts to know the limitations of the equipment in doing their assigned tasks. Mattingly also received training in recognizing geological features from orbit by flying over the field areas in an airplane, and trained to operate the Scientific Instrument Module from lunar orbit.
Apollo 16	Equipment	Equipment thumb\|Apollo 16's launch vehicle by the VAB, January 27, 1972
Apollo 16	Launch vehicle	Launch vehicle The launch vehicle which took Apollo 16 to the Moon was a Saturn V, designated as AS-511. This was the eleventh Saturn V to be flown and the ninth used on crewed missions. Apollo 16's Saturn V was almost identical to Apollo 15's. One change that was made was the restoration of four retrorockets to the S-IC first stage, meaning there would be a total of eight, as on Apollo 14 and earlier. The retrorockets were used to minimize the risk of collision between the jettisoned first stage and the Saturn V. These four retrorockets had been omitted from Apollo 15's Saturn V to save weight, but analysis of Apollo 15's flight showed that the S-IC came closer than expected after jettison, and it was feared that if there were only four rockets and one failed, there might be a collision.
Apollo 16	ALSEP and other surface equipment	ALSEP and other surface equipment As on all lunar landing missions after Apollo 11, an Apollo Lunar Surface Experiments Package (ALSEP) was flown on Apollo 16. This was a suite of nuclear-powered experiments designed to keep functioning after the astronauts who set them up returned to Earth. Apollo 16's ALSEP consisted of a Passive Seismic Experiment (PSE, a seismometer), an Active Seismic Experiment (ASE), a Lunar Heat Flow Experiment (HFE), and a Lunar Surface Magnetometer (LSM). The ALSEP was powered by a SNAP-27 radioisotope thermoelectric generator, developed by the Atomic Energy Commission. thumb\|upright=1.2\|left\|Apollo 16's Passive Seismic Experiment The PSE added to the network of seismometers left by Apollo 12, 14 and 15. NASA intended to calibrate the Apollo 16 PSE by crashing the LM's ascent stage near it after the astronauts were done with it, an object of known mass and velocity impacting at a known location. However, NASA lost control of the ascent stage after jettison, and this did not occur. The ASE, designed to return data about the Moon's geologic structure, consisted of two groups of explosives: one, a line of "thumpers" were to be deployed attached to three geophones. The thumpers would be exploded during the ALSEP deployment. A second group was four mortars of different sizes, to be set off remotely once the astronauts had returned to Earth. Apollo 14 had also carried an ASE, though its mortars were never set off for fear of affecting other experiments. The HFE involved the drilling of two holes into the lunar surface and emplacement of thermometers which would measure how much heat was flowing from the lunar interior. This was the third attempt to emplace a HFE: the first flew on Apollo 13 and never reached the lunar surface, while on Apollo 15, problems with the drill meant the probes did not go as deep as planned. The Apollo 16 attempt would fail after Duke had successfully emplaced the first probe; Young, unable to see his feet in the bulky spacesuit, pulled out and severed the cable after it wrapped around his leg. NASA managers vetoed a repair attempt due to the amount of time it would take. A HFE flew, and was deployed, on Apollo 17. thumb\|upright=1.2\|right\|The Lunar Surface Magnetometer The LSM was designed to measure the strength of the Moon's magnetic field, which is only a small fraction of Earth's. Additional data would be returned by the use of the Lunar Portable Magnetometer (LPM), to be carried on the lunar rover and activated at several geology stops. Scientists also hoped to learn from an Apollo 12 sample, to be briefly returned to the Moon on Apollo 16, from which "soft" magnetism had been removed, to see if it had been restored on its journey. Measurements after the mission found that "soft" magnetism had returned to the sample, although at a lower intensity than before. A Far Ultraviolet Camera/Spectrograph (UVC) was flown, the first astronomical observations taken from the Moon, seeking data on hydrogen sources in space without the masking effect of the Earth's corona. The instrument was placed in the LM's shadow and pointed at nebulae, other astronomical objects, the Earth itself, and any suspected volcanic vents seen on the lunar surface. The film was returned to Earth. When asked to summarize the results for a general audience, Dr. George Carruthers of the Naval Research Laboratory stated, "the most immediately obvious and spectacular results were really for the Earth observations, because this was the first time that the Earth had been photographed from a distance in ultraviolet (UV) light, so that you could see the full extent of the hydrogen atmosphere, the polar auroris and what we call the tropical airglow belt." Four panels mounted on the LM's descent stage comprised the Cosmic Ray Detector, designed to record cosmic ray and solar wind particles. Three of the panels were left uncovered during the voyage to the Moon, with the fourth uncovered by the crew early in the EVA. The panels would be bagged for return to Earth. The free-standing Solar Wind Composition Experiment flew on Apollo 16, as it had on each of the lunar landings, for deployment on the lunar surface and return to Earth. Platinum foil was added to the aluminum of the previous experiments, to minimize contamination.
Apollo 16	Particles and Fields Subsatellite PFS-2	Particles and Fields Subsatellite PFS-2 thumb\|right\|Artist's conception of subsatellite deployment The Apollo 16 Particles and Fields Subsatellite (PFS-2) was a small satellite released into lunar orbit from the service module. Its principal objective was to measure charged particles and magnetic fields all around the Moon as the Moon orbited Earth, similar to its sister spacecraft, PFS-1, released eight months earlier by Apollo 15. The two probes were intended to have similar orbits, ranging from above the lunar surface. Like the Apollo 15 subsatellite, PFS-2 was expected to have a lifetime of at least a year before its orbit decayed and it crashed onto the lunar surface. The decision to bring Apollo 16 home early after there were difficulties with the main engine meant that the spacecraft did not go to the orbit which had been planned for PFS-2. Instead, it was ejected into a lower-than-planned orbit and crashed into the Moon a month later on May 29, 1972, after circling the Moon 424 times. This brief lifetime was because lunar mascons were near to its orbital ground track and helped pull PFS-2 into the Moon.
Apollo 16	Mission events	Mission events Elements of the spacecraft and launch vehicle began arriving at Kennedy Space Center in July 1970, and all had arrived by September 1971. Apollo 16 was originally scheduled to launch on March 17, 1972. One of the bladders for the CM's reaction control system burst during testing. This issue, in combination with concerns that one of the explosive cords that would jettison the LM from the CSM after the astronauts returned from the lunar surface would not work properly, and a problem with Duke's spacesuit, made it desirable to slip the launch to the next launch window. Thus, Apollo 16 was postponed to April 16. The launch vehicle stack, which had been rolled out from the Vehicle Assembly Building on December 13, 1971, was returned thereto on January 27, 1972. It was rolled out again to Launch Complex 39A on February 9. The official mission countdown began on Monday, April 10, 1972, at 8:30 am, six days before the launch. At this point the SaturnV rocket's three stages were powered up, and drinking water was pumped into the spacecraft. As the countdown began, the crew of Apollo 16 was participating in final training exercises in anticipation of a launch on April 16. The astronauts underwent their final preflight physical examination on April 11. The only holds in the countdown were the ones pre-planned in the schedule, and the weather was fair as the time for launch approached.
Apollo 16	Launch and outward journey	Launch and outward journey thumb\|right\|upright=1.3\|Launch of Apollo 16 The Apollo 16 mission launched from the Kennedy Space Center in Florida at 12:54 pm EST on April 16, 1972. The launch was nominal; the crew experienced vibration similar to that on previous missions. The first and second stages of the SaturnV (the S-IC and S-II) performed nominally; the spacecraft entered orbit around Earth just under 12 minutes after lift-off. After reaching orbit, the crew spent time adapting to the zero-gravity environment and preparing the spacecraft for trans-lunar injection (TLI), the burn of the third-stage rocket that would propel them to the Moon. In Earth orbit, the crew faced minor technical issues, including a potential problem with the environmental control system and the S-IVB third stage's attitude control system, but eventually resolved or compensated for them as they prepared to depart towards the Moon. After two orbits, the rocket's third stage reignited for just over five minutes, propelling the craft towards the Moon at about . Six minutes after the burn of the S-IVB, the command and service modules (CSM), containing the crew, separated from the rocket and traveled away from it before turning around and retrieving the lunar module from inside the expended rocket stage. The maneuver, performed by Mattingly and known as transposition, docking, and extraction, went smoothly. Following transposition and docking, the crew noticed the exterior surface of the Lunar Module was giving off particles from a spot where the LM's skin appeared torn or shredded; at one point, Duke estimated they were seeing about five to ten particles per second. Young and Duke entered the Lunar Module through the docking tunnel connecting it with the command module to inspect its systems, at which time they did not spot any major issues. Once on course towards the Moon, the crew put the spacecraft into a rotisserie "barbecue" mode in which the craft rotated along its long axis three times per hour to ensure even heat distribution about the spacecraft from the Sun. After further preparing the craft for the voyage, the crew began the first sleep period of the mission just under 15 hours after launch. left\|thumb\|upright=1.3\|Earth from Apollo 16 during the trans-lunar coast, showing the US at center By the time Mission Control issued the wake-up call to the crew for flight day two, the spacecraft was about away from the Earth, traveling at about . As it was not due to arrive in lunar orbit until flight day four, flight days two and three were largely preparatory, consisting of spacecraft maintenance and scientific research. On day two, the crew performed an electrophoresis experiment, also performed on Apollo 14, in which they attempted to demonstrate that electrophoretic separation in their near-weightless environment could be used to produce substances of greater purity than would be possible on Earth. Using two different sizes of polystyrene particles, one size colored red and one blue, separation of the two types via electrophoresis was achieved, though electro-osmosis in the experiment equipment prevented the clear separation of two particle bands. The remainder of day two included a two-second mid-course correction burn performed by the CSM's service propulsion system (SPS) engine to tweak the spacecraft's trajectory. Later in the day, the astronauts entered the Lunar Module for the second time to further inspect the landing craft's systems. The crew reported they had observed additional paint peeling from a portion of the LM's outer aluminum skin. Despite this, the crew discovered that the spacecraft's systems were performing nominally. Following the LM inspection, the crew reviewed checklists and procedures for the following days in anticipation of their arrival and the Lunar Orbit Insertion (LOI) burn. Command Module Pilot Mattingly reported "gimbal lock", meaning that the system to keep track of the craft's attitude was no longer accurate. Mattingly had to realign the guidance system using the Sun and Moon. At the end of day two, Apollo 16 was about away from Earth. When the astronauts were awakened for flight day three, the spacecraft was about away from the Earth. The velocity of the craft steadily decreased, as it had not yet reached the lunar sphere of gravitational influence. The early part of day three was largely housekeeping, spacecraft maintenance and exchanging status reports with Mission Control in Houston. The crew performed the Apollo light flash experiment, or ALFMED, to investigate "light flashes" that were seen by Apollo lunar astronauts when the spacecraft was dark, regardless of whether their eyes were open. This was thought to be caused by the penetration of the eye by cosmic ray particles. During the second half of the day, Young and Duke again entered the Lunar Module to power it up and check its systems, and perform housekeeping tasks in preparation for the lunar landing. The systems were found to be functioning as expected. Following this, the crew donned their space suits and rehearsed procedures that would be used on landing day. Just before the end of flight day three at 59 hours, 19 minutes, 45 seconds after liftoff, while from the Earth and from the Moon, the spacecraft's velocity began increasing as it accelerated towards the Moon after entering the lunar sphere of influence. After waking up on flight day four, the crew began preparations for the LOI maneuver that would brake them into orbit. At an altitude of the scientific instrument module (SIM) bay cover was jettisoned. At just over 74 hours into the mission, the spacecraft passed behind the Moon, temporarily losing contact with Mission Control. While over the far side, the SPS burned for 6minutes and 15 seconds, braking the spacecraft into an orbit with a low point (pericynthion) of 58.3 and a high point (apocynthion) of 170.4 nautical miles (108.0 and 315.6 km, respectively). After entering lunar orbit, the crew began preparations for the Descent Orbit Insertion (DOI) maneuver to further modify the spacecraft's orbital trajectory. The maneuver decreased the craft's pericynthion to . The remainder of flight day four was spent making observations and preparing for activation of the Lunar Module, undocking, and landing the following day.
Apollo 16	Lunar surface	Lunar surface thumb\|right\|NASA officials conferring on whether to allow the Apollo 16 landing, April 20, 1972 The crew continued preparing for Lunar Module activation and undocking shortly after waking up to begin flight day five. The boom that extended the mass spectrometer in the SIM bay was stuck, semi-deployed. It was decided that Young and Duke would visually inspect the boom after undocking the LM from the CSM. They entered the LM for activation and checkout of the spacecraft's systems. Despite entering the LM 40 minutes ahead of schedule, they completed preparations only 10 minutes early due to numerous delays in the process. With the preparations finished, they undocked 96 hours, 13 minutes, 31 seconds into the mission. For the rest of the two crafts' passes over the near side of the Moon, Mattingly prepared to shift Casper to a higher, near-circular orbit, while Young and Duke prepared Orion for the descent to the lunar surface. At this point, during tests of the CSM's steerable rocket engine in preparation for the burn to modify the craft's orbit, Mattingly detected oscillations in the SPS engine's backup gimbal system. According to mission rules, under such circumstances, Orion was to re-dock with Casper, in case Mission Control decided to abort the landing and use the Lunar Module's engines for the return trip to Earth. Instead, the two craft kept station, maintaining positions close to each other. After several hours of analysis, mission controllers determined that the malfunction could be worked around, and Young and Duke could proceed with the landing. Powered descent to the lunar surface began about six hours behind schedule. Because of the delay, Young and Duke began their descent to the surface at an altitude higher than that of any previous mission, at . After descending to an altitude of about , Young was able to view the landing site in its entirety. Throttle-down of the LM's landing engine occurred on time, and the spacecraft tilted forward to its landing orientation at an altitude of . The LM landed north and west of the planned landing site at 104 hours, 29 minutes, and 35 seconds into the mission, at 2:23:35 UTC on April 21 (8:23:35 pm on April 20 in Houston). The availability of the Lunar Roving Vehicle rendered their distance from the targeted point trivial. After landing, Young and Duke began powering down some of the LM's systems to conserve battery power. Upon completing their initial procedures, the pair configured Orion for their three-day stay on the lunar surface, removed their space suits and took initial geological observations of the immediate landing site. They then settled down for their first meal on the surface. After eating, they configured the cabin for sleep. The landing delay caused by the malfunction in the CSM's main engine necessitated significant modifications to the mission schedule. Apollo 16 would spend one less day in lunar orbit after surface exploration had been completed to afford the crew ample margins in the event of further problems. In order to improve Young's and Duke's sleep schedule, the third and final moonwalk of the mission was trimmed from seven hours to five.
Apollo 16	First moonwalk	First moonwalk After waking up on April 21, Young and Duke ate breakfast and began preparations for the first extravehicular activity (EVA), or moonwalk. After the pair donned and pressurized their space suits and depressurized the Lunar Module cabin, Young climbed out onto the "porch" of the LM, a small platform above the ladder. Duke handed Young a jettison bag full of trash to dispose of on the surface. Young then lowered the equipment transfer bag (ETB), containing equipment for use during the EVA, to the surface. Young descended the ladder and, upon setting foot on the lunar surface, became the ninth human to walk on the Moon. Upon stepping onto the surface, Young expressed his sentiments about being there: "There you are: Mysterious and unknown Descartes. Highland plains. Apollo 16 is gonna change your image. I'm sure glad they got ol' Brer Rabbit, here, back in the briar patch where he belongs." Duke soon descended the ladder and joined Young on the surface, becoming the tenth person to walk on the Moon. Duke was then aged 36; no younger human has ever walked on the lunar surface. Duke expressed his excitement, stating to CAPCOM Anthony England: "Fantastic! Oh, that first foot on the lunar surface is super, Tony!" The pair's first task of the moonwalk was to offload the Lunar Roving Vehicle, the Far Ultraviolet Camera/Spectrograph, and other equipment. This was done without problems. On first driving the lunar rover, Young discovered that the rear steering was not working. He alerted Mission Control to the problem before setting up the television camera, after which Duke erected the United States flag. During lunar surface operations, Commander Young always drove the rover, while Lunar Module Pilot Duke assisted with navigation; this was a division of responsibilities used consistently throughout Apollo's J missions. thumb\|left\|Young driving the LRV during the "Grand Prix" The day's next task was to deploy the ALSEP; while they were parking the lunar rover, on which the TV camera was mounted, to observe the deployment, the rear steering began functioning. After ALSEP deployment, they collected samples in the vicinity. About four hours after the beginning of EVA-1, they mounted the lunar rover and drove to the first geologic stop, Plum Crater, a crater on the rim of Flag Crater, about across. There, at a distance of from the LM, they sampled material in the vicinity, which scientists believed had penetrated through the upper regolith layer to the underlying Cayley Formation. It was there that Duke retrieved, at the request of Mission Control, the largest rock returned by an Apollo mission, a breccia nicknamed Big Muley after mission geology principal investigator William R. Muehlberger. The next stop of the day was Buster Crater, a small crater located north of the larger Spook Crater, about from the LM. There, Duke took pictures of Stone Mountain and South Ray Crater, while Young deployed the LPM. By this point, scientists were beginning to reconsider their pre-mission hypothesis that Descartes had been the setting of ancient volcanic activity, as the two astronauts had yet to find any volcanic material. Following their stop at Buster, Young did a "Grand Prix" demonstration drive of the lunar rover, which Duke filmed with a 16 mm movie camera. This had been attempted on Apollo 15, but the camera had malfunctioned. After completing more tasks at the ALSEP, they returned to the LM to close out the moonwalk. They reentered the LM 7hours, 6minutes, and 56 seconds after the start of the EVA. Once inside, they pressurized the LM cabin, went through a half-hour debriefing with scientists in Mission Control, and configured the cabin for the sleep period.
Apollo 16	Second moonwalk	Second moonwalk thumb\|upright=1.3\|right\|The view from the side of Stone Mountain, which Duke described as "spectacular" Waking up three and a half minutes earlier than planned, they discussed the day's timeline of events with Houston. The second lunar excursion's primary objective was to visit Stone Mountain to climb up the slope of about 20 degrees to reach a cluster of five craters known as "Cinco craters". They drove there in the LRV, traveling from the LM. At above the valley floor, the pair were at the highest elevation above the LM of any Apollo mission. They marveled at the view (including South Ray) from the side of Stone Mountain, which Duke described as "spectacular", then gathered samples in the vicinity. After spending 54 minutes on the slope, they climbed aboard the lunar rover en route to the day's second stop, dubbed Station 5, a crater across. There, they hoped to find Descartes material that had not been contaminated by ejecta from South Ray Crater, a large crater south of the landing site. The samples they collected there, despite still uncertain origin, are according to geologist Wilhelms, "a reasonable bet to be Descartes". The next stop, Station 6, was a blocky crater, where the astronauts believed they could sample the Cayley Formation as evidenced by the firmer soil found there. Bypassing station seven to save time, they arrived at Station 8 on the lower flank of Stone Mountain, where they sampled material on a ray from South Ray crater for about an hour. There, they collected black and white breccias and smaller, crystalline rocks rich in plagioclase. At Station 9, an area known as the "Vacant Lot", which was believed to be free of ejecta from South Ray, they spent about 40 minutes gathering samples. Twenty-five minutes after departing the Vacant Lot, they arrived at the final stop of the day, halfway between the ALSEP site and the LM. There, they dug a double core and conducted several penetrometer tests along a line stretching east of the ALSEP. At the request of Young and Duke, the moonwalk was extended by ten minutes. After returning to the LM to wrap up the second lunar excursion, they climbed back inside the landing craft's cabin, sealing and pressurizing the interior after 7hours, 23 minutes, and 26 seconds of EVA time, breaking a record that had been set on Apollo 15. After eating a meal and proceeding with a debriefing on the day's activities with Mission Control, they reconfigured the LM cabin and prepared for the sleep period.
Apollo 16	Third moonwalk	Third moonwalk thumb\|upright=1.8\|left\|John Young adjusting the LRV's antenna near Shadow Rock Flight day seven was their third and final day on the lunar surface, returning to orbit to rejoin Mattingly in the CSM following the day's moonwalk. During the third and final lunar excursion, they were to explore North Ray crater, the largest of any of the craters any Apollo expedition had visited. After exiting Orion, the pair drove to North Ray crater. The drive was smoother than that of the previous day, as the craters were shallower and boulders were less abundant north of the immediate landing site. After passing Palmetto crater, boulders gradually became larger and more abundant as they approached North Ray in the lunar rover. Upon arriving at the rim of North Ray crater, they were away from the LM. After their arrival, the duo took photographs of the wide and deep crater. They visited a large boulder, taller than a four-story building, which became known as 'House Rock'. Samples obtained from this boulder delivered the final blow to the pre-mission volcanic hypothesis, proving it incorrect. House Rock had numerous bullet hole-like marks where micrometeoroids from space had impacted the rock. About 1hour and 22 minutes after arriving at the North Ray crater, they departed for Station 13, a large boulder field about from North Ray. On the way, they set a lunar speed record, traveling at an estimated downhill. They arrived at a high boulder, which they called "Shadow Rock". Here, they sampled permanently shadowed soil. During this time, Mattingly was preparing the CSM in anticipation of their return approximately six hours later. After three hours and six minutes, they returned to the LM, where they completed several experiments and unloaded the rover. A short distance from the LM, Duke placed a photograph of his family and an Air Force commemorative medallion on the surface. Young drove the rover to a point about east of the LM, known as the 'VIP site,' so its television camera, controlled remotely by Mission Control, could observe Apollo 16's liftoff from the Moon. They then reentered the LM after a 5-hour and 40-minute final excursion. After pressurizing the LM cabin, the crew began preparing to return to lunar orbit.
Apollo 16	Solo activities	Solo activities thumb\|Casper above the Moon After Orion was cleared for the landing attempt, Casper maneuvered away, and Mattingly performed a burn that took his spacecraft to an orbit of in preparation for his scientific work. The SM carried a suite of scientific instruments in its SIM bay, similar to those carried on Apollo 15. Mattingly had compiled a busy schedule operating the various SIM bay instruments, one that became even busier once Houston decided to bring Apollo 16 home a day early, as the flight directors sought to make up for lost time. His work was hampered by various malfunctions: when the Panoramic Camera was turned on, it appeared to take so much power from one of the CSM's electrical systems, that it initiated the spacecraft Master Alarm. It was immediately shut off, though later analysis indicated that the drain might have been from the spacecraft's heaters, which came on at the same time. Its work was also hampered by the delay in the beginning of Caspers orbital scientific work and the early return to Earth, and by a malfunction resulting in the overexposure of many of the photographs. Nevertheless, it was able to take a photograph of the Descartes area in which Orion is visible. The Mass Spectrometer boom did not fully retract following its initial extension, as had happened on Apollo 15, though it retracted far enough to allow the SPS engine to be fired safely when Casper maneuvered away from Orion before the LM began its Moon landing attempt. Although the Mass Spectrometer was able to operate effectively, it stuck near its fully deployed position prior to the burn that preceded rendezvous, and had to be jettisoned. Scientists had hoped to supplement the lunar data gained with more on the trans-Earth coast, but Apollo 15 data could be used instead. The Mapping Camera also did not function perfectly; later analysis found it to have problems with its glare shield. The changes to the flight plan meant that some areas of the lunar surface that were supposed to be photographed could not be; also, a number of images were overexposed. The Laser Altimeter, designed to accurately measure the spacecraft altitude, slowly lost accuracy due to reduced power, and finally failed just before it was due to be used for the last time.
Apollo 16	Return to Earth	Return to Earth thumb\|Ken Mattingly performing his deep-space EVA, retrieving film cassettes from the CSM's exterior Eight minutes before the planned departure from the lunar surface, CAPCOM James Irwin notified Young and Duke from Mission Control that they were go for liftoff. Two minutes before launch, they activated the "Master Arm" switch and then the "Abort Stage" button, causing small explosive charges to sever the ascent stage from the descent stage, with cables connecting the two severed by a guillotine-like mechanism. At the pre-programmed moment, there was liftoff and the ascent stage blasted away from the Moon, as the camera aboard the LRV followed the first moments of the flight. Six minutes after liftoff, at a speed of about , Young and Duke reached lunar orbit. Young and Duke rendezvoused and re-docked with Mattingly in the CSM. To minimize the transfer of lunar dust from the LM cabin into the CSM, Young and Duke cleaned the cabin before opening the hatch separating the two spacecraft. After opening the hatch and reuniting with Mattingly, the crew transferred the samples Young and Duke had collected on the surface into the CSM for transfer to Earth. After transfers were completed, the crew would sleep before jettisoning the empty Lunar Module ascent stage the next day, when it was to be crashed intentionally into the lunar surface in order to calibrate the seismometer Young and Duke had left on the surface. The next day, after final checks were completed, the expended LM ascent stage was jettisoned. Likely because of a failure by the crew to activate a certain switch in the LM before sealing it off, it tumbled after separation. NASA could not control it, and it did not execute the rocket burn necessary for the craft's intentional de-orbit. The ascent stage eventually crashed into the lunar surface nearly a year after the mission. The crew's next task, after jettisoning the Lunar Module ascent stage, was to release a subsatellite into lunar orbit from the CSM's scientific instrument bay. The burn to alter the CSM's orbit to that desired for the subsatellite had been cancelled; as a result, the subsatellite lasted just over a month in orbit, far less than its anticipated one year. Just under five hours after the subsatellite release, on the CSM's 65th orbit around the Moon, its service propulsion system main engine was reignited to propel the craft on a trajectory that would return it to Earth. The SPS engine performed the burn flawlessly despite the malfunction that had delayed their landing several days previously. During the return to Earth, Mattingly performed an 83-minute EVA to retrieve film cassettes from the cameras in the SIM bay, with assistance from Duke who remained at the command module's hatch. At approximately from Earth, it was the second "deep space" EVA in history, performed at great distance from any planetary body. , it remains one of only three such EVAs, all performed during Apollo's J-missions under similar circumstances. During the EVA, Mattingly set up a biological experiment, the Microbial Ecology Evaluation Device (MEED), an experiment unique to Apollo 16, to evaluate the response of microbes to the space environment. The crew carried out various housekeeping and maintenance tasks aboard the spacecraft and ate a meal before concluding the day. The penultimate day of the flight was largely spent performing experiments, aside from a twenty-minute press conference during the second half of the day. During the press conference, the astronauts answered questions pertaining to several technical and non-technical aspects of the mission prepared and listed by priority at the Manned Spacecraft Center in Houston by journalists covering the flight. In addition to numerous housekeeping tasks, the astronauts prepared the spacecraft for its atmospheric reentry the next day. At the end of the crew's final full day in space, the spacecraft was approximately from Earth and closing at a rate of about . When the wake-up call was issued to the crew for their final day in space by CAPCOM England, the CSM was about from Earth, traveling just over . Just over three hours before splashdown in the Pacific Ocean, the crew performed a final course correction burn, using the spacecraft's thrusters to change their velocity by . Approximately ten minutes before reentry into Earth's atmosphere, the cone-shaped command module containing the three crewmembers separated from the service module, which would burn up during reentry. At 265 hours and 37 minutes into the mission, at a velocity of about , Apollo 16 began atmospheric reentry. At its maximum, the temperature of the heat shield was between . After parachute deployment and less than 14 minutes after reentry began, the command module splashed down in the Pacific Ocean southeast of the island of Kiritimati 265 hours, 51 minutes, 5seconds after liftoff. The spacecraft and its crew was retrieved by the aircraft carrier . The astronauts were safely aboard the Ticonderoga 37 minutes after splashdown.
Apollo 16	Scientific results and aftermath	Scientific results and aftermath Scientific analysis of the rocks brought back to Earth confirmed that the Cayley Formation was not volcanic in nature. There was less certainty regarding the Descartes Formation, as it was not clear which if any of the rocks came from there. There was no evidence that showed that Stone Mountain was volcanic. One reason why Descartes had been selected was that it was visually different from previous Apollo landing sites, but rocks from there proved to be closely related to those from the Fra Mauro Formation, Apollo 14's landing site. Geologists realized that they had been so certain that Cayley was volcanic, they had not been open to dissenting views, and that they had been over-reliant on analogues from Earth, a flawed model because the Moon does not share much of the Earth's geologic history. They concluded that there are few if any volcanic mountains on the Moon. These conclusions were informed by observations from Mattingly, the first CMP to use binoculars in his observations, who had seen that from the perspective of lunar orbit, there was nothing distinctive about the Descartes Formation—it fit right in with the Mare Imbrium structure. Other results gained from Apollo 16 included the discovery of two new auroral belts around Earth. After the mission, Young and Duke served as backups for Apollo 17, and Duke retired from NASA in December 1975. Young and Mattingly both flew the Space Shuttle: Young, who served as Chief Astronaut from 1974 to 1987, commanded the first Space Shuttle mission, STS-1 in 1981, as well as STS-9 in 1983, on the latter mission becoming the first person to journey into space six times. He retired from NASA in 2004. Mattingly also twice commanded Shuttle missions, STS-4 (1982) and STS-51-C (1985), before retiring from NASA in 1985.
Apollo 16	Locations of spacecraft and other equipment	Locations of spacecraft and other equipment thumb\|upright=1.3\|right\|Command module Casper at the U.S. Space & Rocket Center in Huntsville, Alabama The Ticonderoga delivered the Apollo 16 command module to the North Island Naval Air Station, near San Diego, California, on Friday, May 5, 1972. On Monday, May 8, ground service equipment being used to empty the residual toxic reaction control system fuel in the command module tanks exploded in a Naval Air Station hangar. Forty-six people were sent to the hospital for 24 to 48 hours' observation, most suffering from inhalation of toxic fumes. Most seriously injured was a technician who suffered a fractured kneecap when a cart overturned on him. A hole was blown in the hangar roof 250 feet above; about 40 windows in the hangar were shattered. The command module suffered a three-inch gash in one panel. The Apollo 16 command module Casper is on display at the U.S. Space & Rocket Center in Huntsville, Alabama, following a transfer of ownership from NASA to the Smithsonian in November 1973. The Lunar Module ascent stage separated from the CSM on April 24, 1972, but NASA lost control of it. It orbited the Moon for about a year. Its impact site remains unknown, though research published in 2023 suggests an impact date of May 29, 1972 (the same as for the subsattelite) and an impact location of 9.99° N, 104.26° E. The S-IVB was deliberately crashed into the Moon. However, due to a communication failure before impact the exact location was unknown until January 2016, when it was discovered within Mare Insularum by the Lunar Reconnaissance Orbiter, approximately southwest of Copernicus Crater. thumb\|left\|Duke left a photo of his family on the Moon. Duke left two items on the Moon, both of which he photographed while there. One is a plastic-encased photo portrait of his family. The reverse of the photo is signed by Duke's family and bears this message: "This is the family of Astronaut Duke from Planet Earth. Landed on the Moon, April 1972." The other item was a commemorative medal issued by the United States Air Force, which was celebrating its 25th anniversary in 1972. He took two medals, leaving one on the Moon and donating the other to the National Museum of the United States Air Force at Wright-Patterson Air Force Base in Ohio. In 2006, shortly after Hurricane Ernesto affected Bath, North Carolina, eleven-year-old Kevin Schanze discovered a piece of metal debris on the ground near his beach home. Schanze and a friend discovered a "stamp" on the flat metal sheet, which upon further inspection turned out to be a faded copy of the Apollo 16 mission insignia. NASA later confirmed the object to be a piece of the first stage of the SaturnV that had launched Apollo 16 into space. In July 2011, after returning the piece of debris at NASA's request, 16-year-old Schanze was given an all-access tour of the Kennedy Space Center and VIP seating for the launch of STS-135, the final mission of the Space Shuttle program.
Apollo 16	See also	See also List of artificial objects on the Moon List of missions to the Moon List of spacewalks and moonwalks 1965–1999
Apollo 16	References	References
Apollo 16	Bibliography	Bibliography
Apollo 16	External links	External links Apollo 16 Traverses, Lunar Photomap 78D2S2(25) On the Moon with Apollo 16: A guidebook to the Descartes Region by Gene Simmons, NASA, EP-95, 1972 Apollo 16: "Nothing so hidden..." (Part 1) – NASA film on the Apollo 16 mission at the Internet Archive Apollo 16: "Nothing so hidden..." (Part 2) – NASA film on the Apollo 16 mission at the Internet Archive Apollo Lunar Surface VR Panoramas – QTVR panoramas at moonpans.com Apollo 16 Science Experiments at the Lunar and Planetary Institute Audio recording of Apollo 16 landing as recorded at the Honeysuckle Creek Tracking Station Interview with the Apollo 16 Astronauts (28 June 1972) from the Commonwealth Club of California Records at the Hoover Institution Archives "Apollo 16: Driving on the Moon" – Apollo 16 film footage of lunar rover at the Astronomy Picture of the Day, 29 January 2013 Astronaut's Eye View of Apollo 16 Site, from LROC Category:Apollo program missions Category:Crewed missions to the Moon Category:Charles Duke Category:Ken Mattingly Category:John Young (astronaut) Category:1972 on the Moon Category:1972 in the United States Category:April 1972 Category:Extravehicular activity Category:LQ20 quadrangle Category:Lunar rovers Category:Sample return missions Category:Soft landings on the Moon Category:Spacecraft launched in 1972 Category:Spacecraft which reentered in 1972 Category:Spacecraft launched by Saturn rockets Category:Successful space missions
Apollo 16	Table of Content	Short description, Crew and key Mission Control personnel, Mission insignia and call signs, Planning and training, Landing site selection, Training, Equipment, Launch vehicle, ALSEP and other surface equipment, Particles and Fields Subsatellite PFS-2, Mission events, Launch and outward journey, Lunar surface, First moonwalk, Second moonwalk, Third moonwalk, Solo activities, Return to Earth, Scientific results and aftermath, Locations of spacecraft and other equipment, See also, References, Bibliography, External links
Apollo 17	Short description	Apollo 17 (December 7–19, 1972) was the eleventh and final mission of NASA's Apollo program, the sixth and most recent time humans have set foot on the Moon. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walked on the Moon, while Command Module Pilot Ronald Evans orbited above. Schmitt was the only professional geologist to land on the Moon; he was selected in place of Joe Engle, as NASA had been under pressure to send a scientist to the Moon. The mission's heavy emphasis on science meant the inclusion of a number of new experiments, including a biological experiment containing five mice that was carried in the command module. Mission planners had two primary goals in deciding on the landing site: to sample lunar highland material older than that at Mare Imbrium and to investigate the possibility of relatively recent volcanic activity. They therefore selected Taurus–Littrow, where formations that had been viewed and pictured from orbit were thought to be volcanic in nature. Since all three crew members had backed up previous Apollo lunar missions, they were familiar with the Apollo spacecraft and had more time for geology training. Launched at 12:33 a.m. Eastern Standard Time (EST) on December 7, 1972, following the only launch-pad delay in the Apollo program, which was caused by a hardware problem, Apollo 17 was a "J-type" mission that included three days on the lunar surface, expanded scientific capability, and the use of the third Lunar Roving Vehicle (LRV). Cernan and Schmitt landed in the Taurus–Littrow valley, completed three moonwalks, took lunar samples and deployed scientific instruments. Orange soil was discovered at Shorty crater; it proved to be volcanic in origin, although from early in the Moon's history. Evans remained in lunar orbit in the command and service module (CSM), taking scientific measurements and photographs. The spacecraft returned to Earth on December 19. The mission broke several records for crewed spaceflight, including the longest crewed lunar landing mission (12 days, 14 hours), greatest distance from a spacecraft during an extravehicular activity of any type (7.6 kilometers or 4.7 miles), longest time on the lunar surface (75 hours), longest total duration of lunar-surface extravehicular activities (22 hours, 4 minutes), largest lunar-sample return (approximately 115 kg or 254 lb), longest time in lunar orbit (6 days, 4 hours), and greatest number of lunar orbits (75).
Apollo 17	Crew and key Mission Control personnel	Crew and key Mission Control personnel In 1969, NASA announced that the backup crew of Apollo 14 would be Gene Cernan, Ronald Evans, and former X-15 pilot Joe Engle. This put them in line to be the prime crew of Apollo 17, because the Apollo program's crew rotation generally meant that a backup crew would fly as prime crew three missions later. Harrison Schmitt, who was a professional geologist as well as an astronaut, had served on the backup crew of Apollo 15, and thus, because of the rotation, would have been due to fly as lunar module pilot on Apollo 18. In September 1970, the plan to launch Apollo 18 was cancelled. The scientific community pressed NASA to assign a geologist, rather than a pilot with non-professional geological training, to an Apollo landing. NASA subsequently assigned Schmitt to Apollo 17 as the lunar module pilot. After that, NASA's director of flight crew operations, Deke Slayton, was left with the question of who would fill the two other Apollo 17 slots: the rest of the Apollo 15 backup crew (Dick Gordon and Vance Brand), or Cernan and Evans from the Apollo 14 backup crew. Slayton ultimately chose Cernan and Evans. Support at NASA for assigning Cernan was not unanimous. Cernan had crashed a Bell 47G helicopter into the Indian River near Cape Kennedy during a training exercise in January 1971; the accident was later attributed to pilot error, as Cernan had misjudged his altitude before crashing into the water. Jim McDivitt, who was manager of the Apollo Spacecraft Program Office at the time, objected to Cernan's selection because of this accident, but Slayton dismissed the concern. After Cernan was offered command of the mission, he advocated for Engle to fly with him on the mission, but it was made clear to him that Schmitt would be assigned instead, with or without Cernan, so he acquiesced. The prime crew of Apollo 17 was publicly announced on August 13, 1971. When assigned to Apollo 17, Cernan was a 38-year-old captain in the United States Navy; he had been selected in the third group of astronauts in 1963, and flown as pilot of Gemini 9A in 1966 and as lunar module pilot of Apollo 10 in 1969 before he served on Apollo 14's backup crew. Evans, 39 years old when assigned to Apollo 17, had been selected as part of the fifth group of astronauts in 1966, and had been a lieutenant commander in the United States Navy. Schmitt, a civilian, was 37 years old when assigned Apollo 17, had a doctorate in geology from Harvard University, and had been selected in the fourth group of astronauts in 1965. Both Evans and Schmitt were making their first spaceflights. For the backup crews of Apollo 16 and 17, the final Apollo lunar missions, NASA selected astronauts who had already flown Apollo lunar missions, to take advantage of their experience, and avoid investing time and money in training rookies who would be unlikely to ever fly an Apollo mission. The original backup crew for Apollo 17, announced at the same time as the prime crew, was the crew of Apollo 15: David Scott as commander, Alfred Worden as CMP and James Irwin as LMP, but in May 1972 they were removed from the backup crew because of their roles in the Apollo 15 postal covers incident. They were replaced with the landing crew of Apollo 16: John W. Young as backup crew commander, Charles Duke as LMP, and Apollo 14's CMP, Stuart Roosa. Originally, Apollo 16's CMP, Ken Mattingly, was to be assigned along with his crewmates, but he declined so he could spend more time with his family, his son having just been born, and instead took an assignment to the Space Shuttle program. Roosa had also served as backup CMP for Apollo 16. For the Apollo program, in addition to the prime and backup crews that had been used in the Mercury and Gemini programs, NASA assigned a third crew of astronauts, known as the support crew. Their role was to provide any assistance in preparing for the missions that the missions director assigned then. Preparations took place in meetings at facilities across the US and sometimes needed a member of the flight crew to attend them. Because McDivitt was concerned that problems could be created if a prime or backup crew member was unable to attend a meeting, Slayton created the support crews to ensure that someone would be able to attend in their stead. Usually low in seniority, they also assembled the mission's rules, flight plan and checklists, and kept them updated; for Apollo 17, they were Robert F. Overmyer, Robert A. Parker and C. Gordon Fullerton. Flight directors were Gerry Griffin, first shift, Gene Kranz and Neil B. Hutchinson, second shift, and Pete Frank and Charles R. Lewis, third shift. According to Kranz, flight directors during the program Apollo had a one-sentence job description, "The flight director may take any actions necessary for crew safety and mission success." Capsule communicators (CAPCOMs) were Fullerton, Parker, Young, Duke, Mattingly, Roosa, Alan Shepard and Joseph P. Allen.
Apollo 17	Mission insignia and call signs	Mission insignia and call signs The insignia's most prominent feature is an image of the Greek sun god Apollo backdropped by a rendering of an American eagle, the red bars on the eagle mirroring those on the U.S. flag. Three white stars above the red bars represent the three crewmembers of the mission. The background includes the Moon, the planet Saturn, and a galaxy or nebula. The wing of the eagle partially overlays the Moon, suggesting humanity's established presence there. thumb\|200px\|left\|Apollo 17 space-flown silver Robbins medallion\|alt=The Apollo seventeen emblem containing Apollo, an eagle made of lines, the Moon, and Saturn; around the outside of the emblem the text Apollo XVII, and then the names Cernan, Evans, and Schmitt. The insignia includes, along with the colors of the U.S. flag (red, white, and blue), the color gold, representative of a "golden age" of spaceflight that was to begin with Apollo 17. The image of Apollo in the mission insignia is a rendering of the Apollo Belvedere sculpture in the Vatican Museums. It looks forward into the future, towards the celestial objects shown in the insignia beyond the Moon. These represent humanity's goals, and the image symbolizes human intelligence, wisdom and ambition. The insignia was designed by artist Robert McCall, based on ideas from the crew. In deciding the call signs for the command module (CM) and lunar module (LM), the crew wished to pay tribute to the American public for their support of the Apollo program, and to the mission, and wanted names with a tradition within American history. The CM was given the call sign "America". According to Cernan, this evoked the 19th century sailing ships which were given that name, and was a thank-you to the people of the United States. The crew selected the name "Challenger" for the LM in lieu of an alternative, "Heritage". Cernan stated that the selected name "just seemed to describe more of what the future for America really held, and that was a challenge". After Schmitt stepped onto the Moon from Challenger, he stated, "I think the next generation ought to accept this as a challenge. Let's see them leave footprints like these."
Apollo 17	Planning and training	Planning and training
Apollo 17	Scheduling and landing site selection	Scheduling and landing site selection Prior to the cancellation of Apollo 18 through 20, Apollo 17 was slated to launch in September 1971 as part of NASA's tentative launch schedule set forth in 1969. The in-flight abort of Apollo 13 and the resulting modifications to the Apollo spacecraft delayed subsequent missions. Following the cancellation of Apollo 20 in early 1970, NASA decided there would be no more than two Apollo missions per year. Part of the reason Apollo 17 was scheduled for December 1972 was to make it fall after the presidential election in November, ensuring that if there was a disaster, it would have no effect on President Richard Nixon's re-election campaign. Nixon had been deeply concerned about the Apollo 13 astronauts, and, fearing another mission in crisis as he ran for re-election, initially decided to omit the funds for Apollo 17 from the budget; he was persuaded to accept a December 1972 date for the mission. Like Apollo 15 and 16, Apollo 17 was slated to be a "J-mission", an Apollo mission type that featured lunar surface stays of three days, higher scientific capability, and the usage of the Lunar Roving Vehicle. Since Apollo 17 was to be the final lunar landing of the Apollo program, high-priority landing sites that had not been visited previously were given consideration for potential exploration. Some sites were rejected at earlier stages. For instance, a landing in the crater Copernicus was rejected because Apollo 12 had already obtained samples from that impact, and three other Apollo expeditions had already visited the vicinity of Mare Imbrium, near the rim of which Copernicus is located. The lunar highlands near the crater Tycho were rejected because of the rough terrain that the astronauts would encounter there. A site on the lunar far side in the crater Tsiolkovskiy was rejected due to technical considerations and the operational costs of maintaining communication with Earth during surface operations. Lastly, a landing in a region southwest of Mare Crisium was rejected on the grounds that a Soviet spacecraft could easily access the site and retrieve samples; Luna 20 ultimately did so shortly after the Apollo 17 site selection was made. Schmitt advocated for a landing on the far side of the Moon until told by Director of Flight Operations Christopher C. Kraft that it would not happen as NASA lacked the funds for the necessary communications satellites. thumb\|left\|Landing site and surrounding area, as imaged from the Apollo 17 command module, 1972\|alt=Black and white photo of a created surface of the Moon showing the landing site and surrounding area for Apollo 17 as taken from Apollo 17. The three sites that made the final consideration for Apollo 17 were Alphonsus crater, Gassendi crater, and the Taurus–Littrow valley. In making the final landing site decision, mission planners considered the primary objectives for Apollo 17: obtaining old highlands material a substantial distance from Mare Imbrium, sampling material from young volcanic activity (i.e., less than three billion years), and having minimal ground overlap with the orbital ground tracks of Apollo 15 and Apollo 16 to maximize the amount of new data obtained. A significant reason for the selection of Taurus–Littrow was that Apollo 15's CMP, Al Worden, had overflown the site and observed features he described as likely volcanic in nature. Gassendi was eliminated because NASA felt that its central peak would be difficult to reach due to the roughness of the local terrain, and, though Alphonsus might be easier operationally than Taurus–Littrow, it was of lesser scientific interest. At Taurus–Littrow, it was believed that the crew would be able to obtain samples of old highland material from the remnants of a landslide event that occurred on the south wall of the valley and the possibility of relatively young, explosive volcanic activity in the area. Although the valley is similar to the landing site of Apollo 15 in that it is on the border of a lunar mare, the advantages of Taurus–Littrow were believed to outweigh the drawbacks. The Apollo Site Selection Board, a committee of NASA personnel and scientists charged with setting out scientific objectives of the Apollo landing missions and selecting landing sites for them, unanimously recommended Taurus–Littrow at its final meeting in February 1972. Upon that recommendation, NASA selected Taurus–Littrow as the landing site for Apollo 17.
Apollo 17	Training	Training thumb\|upright\|Gene Cernan participates in geology training in Sudbury, Ontario, in May 1972\|alt=A photo of Gene Cernan standing on a rock with holding a stick while participating in geology training. As with previous lunar landings, the Apollo 17 astronauts undertook an extensive training program that included learning to collect samples on the surface, usage of the spacesuits, navigation in the Lunar Roving Vehicle, field geology training, survival training, splashdown and recovery training, and equipment training. The geology field trips were conducted as much as possible as if the astronauts were on the Moon: they would be provided with aerial images and maps, and briefed on features of the site and a suggested routing. The following day, they would follow the route, and have tasks and observations to be done at each of the stops. The geology field trips began with one to Big Bend National Park in Texas in October 1971. The early ones were not specifically tailored to prepare the astronauts for Taurus–Littrow, which was not selected until February 1972, but by June, the astronauts were going on field trips to sites specifically selected to prepare for Apollo 17's landing site. Both Cernan and Schmitt had served on backup crews for Apollo landing missions, and were familiar with many of the procedures. Their trainers, such as Gordon Swann, feared that Cernan would defer to Schmitt as a professional geologist on matters within his field. Cernan also had to adjust for the loss of Engle, with whom he had trained for Apollo 14. In spite of these issues, Cernan and Schmitt worked well together as a team, and Cernan became adept at describing what he was seeing on geology field trips, and working independently of Schmitt when necessary. The landing crew aimed for a division of labor so that, when they arrived in a new area, Cernan would perform tasks such as adjusting the antenna on the Lunar Roving Vehicle so as to transmit to Earth while Schmitt gave a report on the geological aspects of the site. The scientists in the geology "backroom" relied on Schmitt's reports to adjust the tasks planned for that site, which would be transmitted to the CapCom and then to Cernan and Schmitt. According to William R. Muehlberger, one of the scientists who trained the astronauts, "In effect [Schmitt] was running the mission from the Moon. But we set it up this way. All of those within the geological world certainly knew it, and I had a sneaking hunch that the top brass knew it too, but this is a practical way out, and they didn't object." Also participating in some of the geology field trips were the commander and lunar module pilot of the backup crew. The initial field trips took place before the Apollo 15 astronauts were assigned as the backup crew for Apollo 17 in February 1972. Either one or both of Scott and Irwin of Apollo 15 took part in four field trips, though both were present together for only two of them. After they were removed from the backup crew, the new backup commander and LMP, Young and Duke, took part in the final four field trips. On field trips, the backup crew would follow half an hour after the prime crew, performing identical tasks, and have their own simulated CapCom and Mission Control guiding them. The Apollo 17 astronauts had fourteen field trips—the Apollo 11 crew had only one. Evans did not go on the geology field trips, having his own set of trainers—by this time, geology training for the CMP was well-established. He would fly with a NASA geologist/pilot, Dick Laidley, over geologic features, with part of the exercise conducted at , and part at to . The higher altitude was equivalent to what could be seen from the planned lunar orbit of about 60 nmi with binoculars. Evans would be briefed for several hours before each exercise, and given study guides; afterwards, there would be debriefing and evaluation. Evans was trained in lunar geology by Farouk El-Baz late in the training cycle; this continued until close to launch. The CMP was given information regarding the lunar features he would overfly in the CSM and which he was expected to photograph.
Apollo 17	Mission hardware and experiments	Mission hardware and experiments thumb\|upright=1.3\|SA-512, Apollo 17's Saturn V rocket, on the launch pad awaiting liftoff, November 1972\|alt=Saturn five rocket on a launch pat at dusk while cloudy outside.
Apollo 17	Spacecraft and launch vehicle	Spacecraft and launch vehicle The Apollo 17 spacecraft comprised CSM-114 (consisting of Command Module 114 (CM-114) and Service Module 114 (SM-114)); Lunar Module 12 (LM-12); a Spacecraft-Lunar Module Adapter (SLA) numbered SLA-21; and a Launch Escape System (LES). The LES contained a rocket motor that would propel the CM to safety in the event of an aborted mission in the moments after launch, while the SLA housed the LM during the launch and early part of the flight. The LES was jettisoned after the launch vehicle ascended to the point that it was not needed, while the SLA was left atop the S-IVB third stage of the rocket after the CSM and LM separated from it. The launch vehicle, SA-512, was one of fifteen Saturn V rockets built, and was the twelfth to fly. With a weight at launch of ( of which was attributable to the spacecraft), Apollo 17's vehicle was slightly lighter than Apollo 16, but heavier than every other crewed Apollo mission.
Apollo 17	Preparation and assembly	Preparation and assembly The first piece of the launch vehicle to arrive at Kennedy Space Center was the S-II second stage, on October 27, 1970; it was followed by the S-IVB on December 21; the S-IC first stage did not arrive until May 11, 1972, followed by the Instrument Unit on June 7. By then, LM-12 had arrived, the ascent stage on June 16, 1971, and the descent stage the following day; they were not mated until May 18, 1972. CM-114, SM-114 and SLA-21 all arrived on March 24, 1972. The rover reached Kennedy Space Center on June 2, 1972. thumb\|upright=1.3\|Cernan (seated, right) and Schmitt in the training Lunar Roving Vehicle, with the mockup Lunar Module in the background, August 1972\|alt=Schmitt, (left), Cernan, (right) in a training LRV, with the Lunar Landing Module in the background. The CM and the service module (SM) were mated on March 28, 1972, and the testing of the spacecraft began that month. The CSM was placed in a vacuum chamber at Kennedy Space Center, and the testing was conducted under those conditions. The LM was also placed in a vacuum chamber; both the prime and the backup crews participated in testing the CSM and LM. During the testing, it was discovered that the LM's rendezvous radar assembly had received too much voltage during earlier tests; it was replaced by the manufacturer, Grumman. The LM's landing radar also malfunctioned intermittently and was also replaced. The front and rear steering motors of the Lunar Roving Vehicle (LRV) also had to be replaced, and it required several modifications. Following the July 1972 removal from the vacuum chamber, the LM's landing gear was installed, and it, the CSM and the SLA were mated to each other. The combined craft was moved into the Vehicle Assembly Building in August for further testing, after which it was mounted on the launch vehicle. After completing testing, including a simulated mission, the LRV was placed in the LM on August 13. Erection of the stages of the launch vehicle began on May 15, 1972, in High Bay 3 of the Vehicle Assembly Building, and was completed on June 27. Since the launch vehicles for Skylab 1 and Skylab 2 were being processed in that building at the same time, this marked the first time NASA had three launch vehicles there since the height of the Apollo program in 1969. After the spacecraft was mounted on the launch vehicle on August 24, it was rolled out to Pad 39-A on August 28. Although this was not the final time a Saturn V would fly (another would lift Skylab to orbit), area residents reacted as though it was, and 5,000 of them watched the rollout, during which the prime crew joined the operating crew from Bendix atop the crawler. At Pad 39-A, testing continued, and the CSM was electrically mated to the launch vehicle on October 11, 1972. Testing concluded with the countdown demonstration tests, accomplished on November 20 and 21. The countdown to launch began at 7:53 a.m. (12:53 UTC) on December 5, 1972.
Apollo 17	Lunar surface science	Lunar surface science
Apollo 17	ALSEP	ALSEP The Apollo Lunar Surface Experiments Package was a suite of nuclear-powered experiments, flown on each landing mission after Apollo 11. This equipment was to be emplaced by the astronauts to continue functioning after the astronauts returned to Earth. For Apollo 17, the ALSEP experiments were a Heat Flow Experiment (HFE), to measure the rate of heat flow from the interior of the Moon, a Lunar Surface Gravimeter (LSG), to measure alterations in the lunar gravity field at the site, a Lunar Atmospheric Composition Experiment (LACE), to investigate what the lunar atmosphere is made up of, a Lunar Seismic Profiling Experiment (LSPE), to detect nearby seismic activity, and a Lunar Ejecta and Meteorites Experiment (LEME), to measure the velocity and energy of dust particles. Of these, only the HFE had been flown before; the others were new. The HFE had been flown on the aborted Apollo 13 mission, as well as on Apollo 15 and 16, but placed successfully only on Apollo 15, and unexpected results from that device made scientists anxious for a second successful emplacement. It was successfully deployed on Apollo 17. The lunar gravimeter was intended to detect wavers in gravity, which would provide support for Albert Einstein's general theory of relativity; it ultimately failed to function as intended. The LACE was a surface-deployed module that used a mass spectrometer to analyze the Moon's atmosphere. On previous missions, the Code Cathode Gauge experiment had measured the quantity of atmospheric particles, but the LACE determined which gases were present: principally neon, helium and hydrogen. The LSPE was a seismic-detecting device that used geophones, which would detect explosives to be set off by ground command once the astronauts left the Moon. When operating, it could only send useful data to Earth in high bit rate, meaning that no other ALSEP experiment could send data then, and limiting its operating time. It was turned on to detect the liftoff of the ascent stage, as well as use of the explosives packages, and the ascent stage's impact, and thereafter about once a week, as well as for some 100 hour periods. The LEME had a set of detectors to measure the characteristics of the dust particles it sought. It was hoped that the LEME would detect dust impacting the Moon from elsewhere, such as from comets or interstellar space, but analysis showed that it primarily detected dust moving at slow speeds across the lunar surface. All powered ALSEP experiments that remained active were deactivated on September 30, 1977, principally because of budgetary constraints.
Apollo 17	Other lunar-surface science	Other lunar-surface science thumb\|Apollo 17's Lunar Roving Vehicle. The Surface Electrical Properties (SEP) experiment receiver is the antenna on the right-rear of the vehicle\|alt=Black and white photo of a lunar rover with a lunar landing module in the background.Like Apollo 15 and 16, Apollo 17 carried a Lunar Roving Vehicle. In addition to being used by the astronauts for transport from station to station on the mission's three moonwalks, the LRV was used to transport the astronauts' tools, communications equipment, and the lunar samples they gathered. The Apollo 17 LRV was also used to carry some of the scientific instruments, such as the Traverse Gravimeter Experiment (TGE) and Surface Electrical Properties (SEP) experiment. The Apollo 17 LRV traveled a cumulative distance of approximately in a total drive time of about four hours and twenty-six minutes; the greatest distance Cernan and Schmitt traveled from the lunar module was about . This was the only mission to carry the TGE, which was built by Draper Laboratory at the Massachusetts Institute of Technology. As gravimeters had been useful in studying the Earth's internal structure, the objective of this experiment was to do the same on the Moon. The gravimeter was used to obtain relative gravity measurements at the landing site in the immediate vicinity of the lunar module, as well as various locations on the mission's traverse routes. Scientists would then use this data to help determine the geological substructure of the landing site and the surrounding vicinity. Measurements were taken while the TGE was mounted on the LRV, and also while the device was placed on the lunar surface. A total of 26 measurements were taken with the TGE during the mission's three moonwalks, with productive results. The SEP was also unique to Apollo 17, and included two major components: a transmitting antenna deployed near the lunar module and a receiver mounted on the LRV. At different stops during the mission's traverses, electrical signals traveled from the transmitting device, through the ground, and were received at the LRV. The electrical properties of the lunar regolith could be determined by comparison of the transmitted and received electrical signals. The results of this experiment, which are consistent with lunar rock composition, show that there is almost no water in the area of the Moon in which Apollo 17 landed, to a depth of . A long, diameter device, the Lunar Neutron Probe was inserted into one of the holes drilled into the surface to collect core samples. It was designed to measure the quantity of neutrons which penetrated to the detectors it bore along its length. This was intended to measure the rate of the "gardening" process on the lunar surface, whereby the regolith on the surface is slowly mixed or buried due to micrometeorites and other events. Placed during the first EVA, it was retrieved during the third and final EVA. The astronauts brought it with them back to Earth, and the measurements from it were compared with the evidence of neutron flux in the core that had been removed from the hole it had been placed in. Results from the probe and from the cores were instrumental in current theories that the top centimeter of lunar regolith turns over every million years, whereas "gardening" to a depth of one meter takes about a billion years.
Apollo 17	Orbital science	Orbital science
Apollo 17	Biological experiments	Biological experiments Apollo 17's CM carried a biological cosmic ray experiment (BIOCORE), containing five mice that had been implanted with radiation monitors under their scalps to see whether they suffered damage from cosmic rays. These animals were placed in individual metal tubes inside a sealed container that had its own oxygen supply, and flown on the mission. All five were pocket mice (Perognathus longimembris); this species was chosen because it was well-documented, small, easy to maintain in an isolated state (not requiring drinking water during the mission and with highly concentrated waste), and for its ability to withstand environmental stress. Officially, the mice—four male and one female—were assigned the identification numbers A3326, A3400, A3305, A3356 and A3352. Unofficially, according to Cernan, the Apollo 17 crew dubbed them Fe, Fi, Fo, Fum, and Phooey. Four of the five mice survived the flight, though only two of them appeared healthy and active; the cause of death of the fifth mouse was not determined. Of those that survived, the study found lesions in the scalp itself and, in one case, the liver. The scalp lesions and liver lesions appeared to be unrelated to one another; nothing was found that could be attributed to cosmic rays. The Biostack experiment was similar to one carried on Apollo 16, and was designed to test the effects of the cosmic rays encountered in space travel on microorganisms that were included, on seeds, and on the eggs of simple animals (brine shrimp and beetles), which were carried in a sealed container. After the mission, the microorganisms and seeds showed little effect, but many of the eggs of all species failed to hatch, or to mature normally; many died or displayed abnormalities.
Apollo 17	Scientific Instrument Module	Scientific Instrument Module thumb\|upright=1.2\|right\|Apollo 17 SIM bay on the service module America, seen from the Lunar Module Challenger in orbit around the Moon The Apollo 17 SM contained the scientific instrument module (SIM) bay. The SIM bay housed three new experiments for use in lunar orbit: a lunar sounder, an infrared scanning radiometer, and a far-ultraviolet spectrometer. A mapping camera, panoramic camera, and a laser altimeter, which had been carried previously, were also included in the SIM bay. The lunar sounder was to beam electromagnetic impulses toward the lunar surface, which were designed with the objective of obtaining data to assist in developing a geological model of the interior of the Moon to an approximate depth of . The infrared scanning radiometer was designed with the objective of generating a temperature map of the lunar surface to aid in locating surface features such as rock fields, structural differences in the lunar crust, and volcanic activity. The far-ultraviolet spectrometer was to be used to obtain information on the composition, density, and constituency of the lunar atmosphere. The spectrometer was also designed to detect far-UV radiation emitted by the Sun that had been reflected off the lunar surface. The laser altimeter was designed to measure the altitude of the spacecraft above the lunar surface within approximately , providing altitude information to the panoramic and mapping cameras, which were also in the SIM bay.
Apollo 17	Light-flash phenomenon and other experiments	Light-flash phenomenon and other experiments Beginning with Apollo 11, crew members observed light flashes that penetrated their closed eyelids. These flashes, described by the astronauts as "streaks" or "specks" of light, were usually observed while the spacecraft was darkened during a sleep period. These flashes, while not observed on the lunar surface, would average about two per minute and were observed by the crew members during the trip out to the Moon, back to Earth, and in lunar orbit. The Apollo 17 crew repeated an experiment, also conducted on Apollo 16, with the objective of linking these light flashes with cosmic rays. Evans wore a device over his eyes that recorded the time, strength, and path of high-energy atomic particles that penetrated the device, while the other two wore blindfolds to keep out light. Investigators concluded that the available evidence supports the hypothesis that these flashes occur when charged particles travel through the retina in the eye. Apollo 17 carried a sodium-iodide crystal identical to the ones in the gamma-ray spectrometer flown on Apollo 15 and 16. Data from this, once it was examined on Earth, was to be used to help form a baseline, allowing for subtraction of rays from the CM or from cosmic radiation to gain better data from the earlier results. In addition, the S-band transponders in the CSM and LM were pointed at the Moon to gain data on its gravitational field. Results from the Lunar Orbiter probes had revealed that lunar gravity varies slightly due to the presence of mass concentrations, or "mascons". Data from the missions, and from the lunar subsatellites left by Apollo 15 and 16, were used to map such variations in lunar gravity.
Apollo 17	Mission events	Mission events
Apollo 17	Launch and outbound trip	Launch and outbound trip thumb\|right\|Apollo 17 launches on December 7, 1972 Originally planned to launch on December 6, 1972, at 9:53 p.m. EST (2:53 a.m. on December 7 UTC), Apollo 17 was the final crewed SaturnV launch, and the only one to occur at night. The launch was delayed by two hours and forty minutes due to an automatic cutoff in the launch sequencer at the T−30 second mark in the countdown. The cause of the problem was quickly determined to be the launch sequencer's failure to automatically pressurize the liquid oxygen tank in the third stage of the rocket; although launch control noticed this and manually caused the tank to pressurize, the sequencer did not recognize the fix and therefore paused the countdown. The clock was reset and held at the T−22 minute mark while technicians worked around the malfunction in order to continue with the launch. This pause was the only launch delay in the Apollo program caused by a hardware problem. The countdown then resumed, and the liftoff occurred at 12:33 a.m. EST on December 7, 1972. The launch window, which had begun at the originally planned launch time of 9:53 p.m. on December 6, remained open until 1:31 a.m., the latest time at which a launch could have occurred during the December 6–7 window. Approximately 500,000 people observed the launch in the immediate vicinity of Kennedy Space Center, despite the early-morning hour. The launch was visible as far away as , and observers in Miami, Florida, reported a "red streak" crossing the northern sky. Among those in attendance at the program's final launch were astronauts Neil Armstrong and Dick Gordon, as well as centenarian Charlie Smith, who alleged he was 130 years old at the time of Apollo 17. The ascent resulted in an orbit with an altitude and velocity almost exactly that which had been planned. In the hours following the launch, Apollo 17 orbited the Earth while the crew spent time monitoring and checking the spacecraft to ensure its readiness to depart Earth orbit. At 3:46 a.m. EST, the S-IVB third stage was reignited for the 351-second trans-lunar injection burn to propel the spacecraft towards the Moon. Ground controllers chose a faster trajectory for Apollo 17 than originally planned to allow the vehicle to reach lunar orbit at the planned time, despite the launch delay. The Command and Service Module separated from the S-IVB approximately half an hour following the S-IVB trans-lunar injection burn, after which Evans turned the spacecraft to face the LM, still attached to the S-IVB. The CSM then docked with the LM and extracted it from the S-IVB. Following the LM extraction, Mission Control programmed the S-IVB, no longer needed to propel the spacecraft, to impact the Moon and trip the seismometers left by prior Apollo crews. It struck the Moon just under 87 hours into the mission, triggering the seismometers from Apollo 12, 14, 15 and 16. Approximately nine hours after launch, the crew concluded the mission's first day with a sleep period, until waking up to begin the second day. thumb\|upright=1.2\|left\|View of Earth from Apollo 17 while in transit to the Moon, a photo now known as The Blue Marble Mission Control and the crew decided to shorten the mission's second day, the first full day in space, in order to adjust the crew's wake-up times for the subsequent days in preparation for an early morning (EST) wake-up time on the day of the lunar landing, then scheduled for early afternoon (EST). This was done since the first day of the mission had been extended because of the launch delay. Following the second rest period, and on the third day of the mission, the crew executed the first mid-course correction, a two-second burn of the CSM's service propulsion engine to adjust the spacecraft's Moon-bound trajectory. Following the burn, the crew opened the hatch separating the CSM and LM in order to check the LM's systems and concluded that they were nominal. So that events would take place at the time indicated in the flight plan, the mission clocks were moved ahead by 2 hours and 40 minutes, the amount of the launch delay, with one hour of it at 45:00:00 into the mission and the remainder at 65:00:00. Among their other activities during the outbound trip, the crew photographed the Earth from the spacecraft as it travelled towards the Moon. One of these photographs is now known as The Blue Marble. The crew found that one of the latches holding the CSM and LM together was unlatched. While Schmitt and Cernan were engaged in a second period of LM housekeeping beginning just before sixty hours into the Mission, Evans worked on the balky latch. He was successful, and left it in the position it would need to be in for the CSM-LM docking that would occur upon return from the lunar surface. Also during the outward journey, the crew performed a heat flow and convection demonstration, as well as the Apollo light-flash experiment. A few hours before entry into lunar orbit, the SIM door on the SM was jettisoned. At approximately 2:47 p.m. EST on December 10, the service propulsion system engine on the CSM ignited to slow down the CSM/LM stack into lunar orbit. Following orbit insertion and orbital stabilization, the crew began preparations for the landing at Taurus–Littrow.
Apollo 17	Lunar landing	Lunar landing thumb\|upright=1.4\|The valley of Taurus-Littrow as seen from the Lunar Module Challenger on the orbit before powered descent there. The Command and Service Module America can just be seen crossing the base of the 2.3 km high South Massif. Between the South and North Massifs, the valley is 7 km wide. Mare Serenitatis, the Sea of Serenity, is on the horizon. The day of the landing began with a checkout of the Lunar Module's systems, which revealed no problems preventing continuation of the mission. Cernan, Evans, and Schmitt each donned their spacesuits, and Cernan and Schmitt entered the LM in preparation for separating from the CSM and landing. The LM undocked from the CSM, and the two spacecraft orbited close together for about an hour and a half while the astronauts made visual inspections and conducted their final pre-landing checks. After finally separating from the CSM, the LM Challenger and its crew of two adjusted their orbit, such that its lowest point would pass about above the landing site, and began preparations for the descent to Taurus–Littrow. While Cernan and Schmitt prepared for landing, Evans remained in orbit to take observations, perform experiments and await the return of his crewmates a few days later. Soon after completing their preparations for landing and just over two hours following the LM's undocking from the CSM, Cernan and Schmitt began their descent to the Taurus–Littrow valley on the lunar surface with the ignition of the Lunar Module's descent propulsion system (DPS) engine. Approximately ten minutes later, as planned, the LM pitched over, giving Cernan and Schmitt their first look at the landing site during the descent phase and allowing Cernan to guide the spacecraft to a desirable landing target while Schmitt provided data from the flight computer essential for landing. The LM touched down on the lunar surface at 2:55 p.m. EST on December 11, just over twelve minutes after DPS ignition. Challenger landed about east of the planned landing point. Shortly thereafter, the two astronauts began re-configuring the LM for their stay on the surface and began preparations for the first moonwalk of the mission, or EVA-1.
Apollo 17	Lunar surface	Lunar surface
Apollo 17	First EVA	First EVA thumb\|upright=1.3\|right\|Cernan on the lunar surface, December 13, 1972 During their approximately 75-hour stay on the lunar surface, Cernan and Schmitt performed three moonwalks (EVAs). The astronauts deployed the LRV, then emplaced the ALSEP and the seismic explosive charges. They drove the rover to nine planned geological-survey stations to collect samples and make observations. Additionally, twelve short sampling stops were made at Schmitt's discretion while riding the rover, during which the astronauts used a handled scoop to get a sample, without dismounting. During lunar-surface operations, Commander Cernan always drove the rover, while Lunar Module Pilot Schmitt was a passenger who assisted with navigation. This division of responsibilities between the two crew positions was used consistently throughout Apollo's J-missions. The first lunar excursion began four hours after landing, at 6:54 p.m. EST on December 11. After exiting through the hatch of the LM and descending the ladder to the footpad, Cernan took the first step on the lunar surface of the mission. Just before doing so, Cernan remarked, "I'm on the footpad. And, Houston, as I step off at the surface at Taurus–Littrow, we'd like to dedicate the first step of Apollo 17 to all those who made it possible." After Cernan surveyed the exterior of the LM and commented on the immediate landing site, Schmitt joined Cernan on the surface. The first task was to offload the rover and other equipment from the LM. While working near the rover, Cernan caught his hammer under the right-rear fender extension, accidentally breaking it off. A similar incident occurred on Apollo 16 as John Young maneuvered around the rover. Although this was not a mission-critical issue, the loss of the part caused Cernan and Schmitt to be covered with dust stirred up when the rover was in motion. The crew made a short-lived fix using duct tape at the beginning of the second EVA, attaching a paper map to the damaged fender. Lunar dust stuck to the tape's surface, however, preventing it from adhering properly. Following deployment and testing the maneuverability of the rover, the crew deployed the ALSEP just west of the landing site. The ALSEP deployment took longer than had been planned, with the drilling of core holes presenting some difficulty, meaning the geological portion of the first EVA would need to be shortened, cancelling a planned visit to Emory crater. Instead, following the deployment of the ALSEP, Cernan and Schmitt drove to Steno crater, to the south of the landing site. The objective at Steno was to sample the subsurface material excavated by the impact that formed the crater. The astronauts gathered of samples, took seven gravimeter measurements, and deployed two explosive packages. The explosive packages were later detonated remotely; the resulting explosions detected by geophones placed by the astronauts and also by seismometers left during previous missions. The first EVA ended after seven hours and twelve minutes. and the astronauts remained in the pressurized LM for the next 17 hours.
Apollo 17	Second EVA	Second EVA thumb\|Astronauts Cernan and Schmitt singing "I Was Strolling on the Moon One Day" to the words and tune of the 1884 song "While Strolling Through the Park One Day" On December 12, awakened by a recording of "Ride of the Valkyries" played from Mission Control, Cernan and Schmitt began their second lunar excursion. The first order of business was to provide the rover's fender a better fix. Overnight, the flight controllers devised a procedure communicated by John Young: taping together four stiff paper maps to form a "replacement fender extension" and then clamping it onto the fender. The astronauts carried out the new fix which did its job without failing until near the end of the third excursion. Cernan and Schmitt then departed for station 2—Nansen Crater, at the foot of the South Massif. When they arrived, their range from the Challenger was 7.6 kilometers (4.7 miles, 25,029 feet). This remains the furthest distance any spacefarers have ever traveled away from the safety of a pressurizable spacecraft while on a planetary body, and also during an EVA of any type. The astronauts were at the extremity of their "walkback limit", a safety constraint meant to ensure that they could walk back to the LM if the rover failed. They began a return trip, traveling northeast in the rover. At station 3, Schmitt fell to the ground while working, looking so awkward that Parker jokingly told him that NASA's switchboard had lit up seeking Schmitt's services for Houston's ballet group, and the site of station 3 was in 2019 renamed Ballet Crater. Cernan took a sample at Station 3 that was to be maintained in vacuum until better analytical techniques became available, joking with the CAPCOM, Parker, about placing a note inside. The container remained unopened until 2022. Stopping at station 4—Shorty crater—the astronauts discovered orange soil, which proved to be very small beads of volcanic glass formed over 3.5 billion years ago. This discovery caused great excitement among the scientists at Mission Control, who felt that the astronauts may have discovered a volcanic vent. However, post-mission sample analysis revealed that Shorty is not a volcanic vent, but rather an impact crater. Analysis also found the orange soil to be a remnant of a lava fountain. This lava fountain sprayed molten lava high into the lunar sky in the Moon's early days, some 3.5 billion years ago and long before Shorty's creation. The orange volcanic beads were droplets of molten lava from the fountain that solidified and were buried by lava deposits until exposed by the impact that formed Shorty, less than 20 million years ago. The final stop before returning to the LM was Camelot crater; throughout the sojourn, the astronauts collected of samples, took another seven gravimeter measurements, and deployed three more explosive packages. Concluding the EVA at seven hours and thirty-seven minutes, Cernan and Schmitt had completed the longest-duration EVA in history to-date, traveling further away from a spacecraft and covering more ground on a planetary body during a single EVA than any other spacefarers. The improvised fender had remained intact throughout, causing the president of the "Auto Body Association of America" to award them honorary lifetime membership.
Apollo 17	Third EVA	Third EVA thumb\|upright=1.5\|Composite image of Harrison Schmitt working next to Tracy's Rock during EVA-3 The third moonwalk, the last of the Apollo program, began at 5:25 p.m. EST on December 13. Cernan and Schmitt rode the rover northeast of the landing site, exploring the base of the North Massif and the Sculptured Hills. Stopping at station 6, they examined a house-sized split boulder dubbed Tracy's Rock (or Split Rock), after Cernan's daughter. The ninth and final planned station was conducted at Van Serg crater. The crew collected of lunar samples and took another nine gravimeter measurements. Schmitt had seen a fine-grained rock, unusual for that vicinity, earlier in the mission and had stood it on its edge; before closing out the EVA, he went and got it. Subsequently, designated Sample 70215, it was, at , the largest rock brought back by Apollo 17. A small piece of it is on exhibit at the Smithsonian Institution, one of the few rocks from the Moon that the public may touch. Schmitt also collected a sample, designated as Sample 76535, at geology station 6 near the base of the North Massif; the sample, a troctolite, was later identified as the oldest known "unshocked" lunar rock, meaning it has not been damaged by high-impact geological events. Scientists have therefore used Sample 76535 in thermochronological studies to determine if the Moon formed a metallic core or, as study results suggest, a core dynamo. Before concluding the moonwalk, the crew collected a breccia rock, dedicating it to the nations of Earth, 70 of which were represented by students touring the U.S. and present in Mission Control Center in Houston, Texas, at the time. Portions of this sample, known as the Friendship Rock, were subsequently distributed to the nations represented by the students. A plaque located on the LM, commemorating the achievements made during the Apollo program, was then unveiled. Before reentering the LM for the final time, Cernan remarked, Cernan then followed Schmitt into the LM; the final lunar excursion had a duration of seven hours and fifteen minutes. Following closing of the LM hatch and repressurization of the LM cabin, Cernan and Schmitt removed their spacesuits and reconfigured the cabin for a final rest period on the lunar surface. As they did following each of the previous two EVAs, Cernan and Schmitt discussed their geological observations from the day's excursion with mission control while preparing to rest.
Apollo 17	Solo activities	Solo activities While Cernan and Schmitt were on the lunar surface, Evans remained alone in the CSM in lunar orbit and was assigned a number of observational and scientific tasks to perform while awaiting the return of his crewmates. In addition to the operation of the various orbital science equipment contained in the CSM's SIM bay, Evans conducted both visual and photographic observation of surface features from his aerial vantage point. The orbit of the CSM having been modified to an elliptical orbit in preparation for the LM's departure and eventual descent, one of Evans' solo tasks in the CSM was to circularize its orbit such that the CSM would remain at approximately the same distance above the surface throughout its orbit. Evans observed geological features visible to him and used handheld cameras to record certain visual targets. Evans also observed and sketched the solar corona at "sunrise," or the period of time during which the CSM would pass from the darkened portion of the Moon to the illuminated portion when the Moon itself mostly obscured the sun. To photograph portions of the surface that were not illuminated by the sun while Evans passed over them, Evans relied in conjunction on exposure and Earthlight. Evans photographed such features as the craters Eratosthenes and Copernicus, as well as the vicinity of Mare Orientale, using this technique. According to the Apollo 17 Mission Report, Evans was able to capture all scientific photographic targets, as well as some other targets of interest. thumb\|left\|An oblique, black-and-white view of a portion of Mare Orientale from the CSM, illustrating the illuminating effect of Earthlight on the lunar terrain below during local nighttime; Evans reported seeing a light "flash" apparently originating from the surface in this area Similarly to the crew of Apollo 16, Evans (as well as Schmitt, while in lunar orbit) reported seeing light "flashes" apparently originating from the lunar surface, known as transient lunar phenomena (TLP); Evans reported seeing these "flashes" in the vicinity of Grimaldi crater and Mare Orientale. The causes of TLP are not well-understood and, though inconclusive as an explanation, both of the sites in which Evans reported seeing TLP are the general locations of outgassing from the Moon's interior. Meteorite impacts are another possible explanation. The flight plan kept Evans busy, making him so tired he overslept one morning by an hour, despite the efforts of Mission Control to awaken him. Before the LM departed for the lunar surface, Evans had discovered that he had misplaced his pair of scissors, necessary to open food packets. Cernan and Schmitt lent him one of theirs. The instruments in the SIM bay functioned without significant hindrance during the orbital portion of the mission, though the lunar sounder and the mapping camera encountered minor problems. Evans spent approximately 148 total hours in lunar orbit, including solo time and time spent together with Cernan and Schmitt, which is more time than any other individual has spent orbiting the Moon. Evans was also responsible for piloting the CSM during the orbital phase of the mission, maneuvering the spacecraft to alter and maintain its orbital trajectory. In addition to the initial orbital recircularization maneuver shortly after the LM's departure, one of the solo activities Evans performed in the CSM in preparation for the return of his crewmates from the lunar surface was the plane change maneuver. This maneuver was meant to align the CSM's trajectory to the eventual trajectory of the LM to facilitate rendezvous in orbit. Evans fired the SPS engine of the CSM for about 20 seconds in successfully adjusting the CSM's orbital plane.
Apollo 17	Return to Earth	Return to Earth thumb\|right\|Apollo 17 post-splashdown recovery operations Cernan and Schmitt lifted off from the lunar surface in the ascent stage of the LM on December14, at 5:54 p.m. EST. The return to lunar orbit took just over seven minutes. The LM, piloted by Cernan, and the CSM, piloted by Evans, maneuvered, and redocked about two hours after liftoff from the surface. After docking, the crew transferred equipment and lunar samples from the LM to the CSM for return to Earth. The crew sealed the hatches between the CSM and the LM ascent stage following completion of the transfer and the LM was jettisoned at 11:51 p.m. EST on December14. The unoccupied ascent stage was then remotely deorbited, crashing it into the Moon with an impact recorded by the seismometers left by Apollo 17 and previous missions. At 6:35 p.m. EST on December16, the CSM's SPS engine was ignited once more to propel the spacecraft away from the Moon on a trajectory back towards Earth. The trans-Earth injection SPS burn lasted just over two minutes. During the return to Earth, Evans performed a 65-minute EVA to retrieve film cassettes from the service module's SIM bay, with assistance from Schmitt who remained at the command module's hatch. At approximately 160,000 nautical miles (184,000 mi; 296,000 km) from Earth, it was the third "deep space" EVA in history, performed at great distance from any planetary body. As of , it remains one of only three such EVAs, all performed during Apollo's J-missions under similar circumstances. It was the last EVA of the Apollo program. During the trip back to Earth, the crew operated the infrared radiometer in the SM, as well as the ultraviolet spectrometer. One midcourse correction was performed, lasting 9 seconds. On December 19, the crew jettisoned the no-longer-needed SM, leaving only the CM for return to Earth. The Apollo 17 spacecraft reentered Earth's atmosphere and splashed down safely in the Pacific Ocean at 2:25 p.m. EST, from the recovery ship, . Cernan, Evans, and Schmitt were then retrieved by a recovery helicopter piloted by Commander Edward E. Dahill, III and were safe aboard the recovery ship 52 minutes after splashdown. As the final Apollo mission concluded successfully, Mission Control in Houston was filled with many former flight controllers and astronauts, who applauded as America returned to Earth.
Apollo 17	Aftermath and spacecraft locations	Aftermath and spacecraft locations thumb\|upright=1.25\|Apollo 17 command module America, on display at Space Center Houston thumb\|upright=1.25\|Lunar Reconnaissance Orbiter image of the Apollo 17 mission site taken in 2011, the Challenger descent stage is in the center, the Lunar Roving Vehicle appears in the lower right. Following their mission, the crew undertook both domestic and international tours, visiting 29 states and 11 countries. The tour kicked off at Super Bowl VII, with the crew leading the crowd in the Pledge of Allegiance; the CM America was also displayed during the pregame activities. None of the Apollo 17 astronauts flew in space again. Cernan retired from NASA and the Navy in 1976. He died in 2017. Evans retired from the Navy in 1976 and from NASA in 1977, entering the private sector. He died in 1990. Schmitt resigned from NASA in 1975 prior to his successful run for a United States Senate seat from New Mexico in 1976. There, he served one six-year term. The Command Module America is currently on display at Space Center Houston at the Lyndon B. Johnson Space Center in Houston, Texas. The ascent stage of Lunar Module Challenger impacted the Moon on December 15, 1972, at 06:50:20.8 UTC (1:50 a.m. EST), at . The descent stage remains on the Moon at the landing site, . In 2023, a study of Apollo-era data from the Lunar Seismic Profiling Experiment showed that the descent stage was causing very slight tremors each lunar morning as components expanded in the heat. Eugene Cernan's flown Apollo 17 spacesuit is in the collection of the Smithsonian's National Air and Space Museum (NASM), where it was transferred in 1974, and Harrison Schmitt's is in storage at NASM's Paul E. Garber Facility. Amanda Young of NASM indicated in 2004 that Schmitt's suit is in the best condition of the flown Apollo lunar spacesuits, and therefore is not on public display. Ron Evans' spacesuit was also transferred from NASA in 1974 to the collection of the NASM; it remains in storage. Since Apollo 17's return, there have been attempts to photograph the landing site, where the LM's descent stage, LRV and some other mission hardware, remain. In 2009 and again in 2011, the Lunar Reconnaissance Orbiter photographed the landing site from increasingly low orbits. At least one group has indicated an intention to visit the site as well; in 2018, the German space company PTScientists said that it planned to land two lunar rovers nearby.
Apollo 17	See also	See also List of Apollo missions List of missions to the Moon List of astronauts by year of selection List of human spaceflights List of human spaceflight programs List of landings on extraterrestrial bodies List of crewed spacecraft List of NASA missions List of spacewalks and moonwalks 1965–1999 Moon landing The Case of the Missing Moon Rocks Apollo in Real Time
Apollo 17	Notes	Notes
Apollo 17	References	References
Apollo 17	Bibliography	Bibliography
Apollo 17	External links	External links Apollo 17 Traverses, 43D1S2(25), Lunar Photomap at Lunar and Planetary Institute "Apollo 17" – Detailed mission information by David R. Williams, NASA Goddard Space Flight Center "Table 2-45. Apollo 17 Characteristics" from NASA Historical Data Book: Volume III: Programs and Projects 1969–1978 by Linda Neuman Ezell, NASA SP-4012, NASA History Series (1988) Apollo 17 Lunar Surface Journal "Apollo 17 Real-Time Mission Experience" – All mission audio, film, video, and photography presented in real-time. Apollo 17 Mission Experiments Overview at the Lunar and Planetary Institute Apollo 17 Voice Transcript Pertaining to the Geology of the Landing Site (PDF) by N. G. Bailey and G. E. Ulrich, United States Geological Survey, 1975 "Apollo Program Summary Report" (PDF), NASA, JSC-09423, April 1975 The Apollo Spacecraft: A Chronology NASA, NASA SP-4009 "The Final Flight" – Excerpt from the September 1973 issue of National Geographic magazine Category:Gene Cernan Category:Ronald Evans (astronaut) Category:Harrison Schmitt Category:1972 in the United States Category:Apollo program missions Category:Articles containing video clips Category:Extravehicular activity Category:LQ12 quadrangle Category:Lunar rovers Category:Crewed missions to the Moon Category:Sample return missions Category:Soft landings on the Moon Category:Spacecraft launched in 1972 Category:Spacecraft which reentered in 1972 Category:Last events Category:December 1972 Category:Spacecraft launched by Saturn rockets Category:1972 on the Moon Category:Successful space missions
Apollo 17	Table of Content	Short description, Crew and key Mission Control personnel, Mission insignia and call signs, Planning and training, Scheduling and landing site selection, Training, Mission hardware and experiments, Spacecraft and launch vehicle, Preparation and assembly, Lunar surface science, ALSEP, Other lunar-surface science, Orbital science, Biological experiments, Scientific Instrument Module, Light-flash phenomenon and other experiments, Mission events, Launch and outbound trip, Lunar landing, Lunar surface, First EVA, Second EVA, Third EVA, Solo activities, Return to Earth, Aftermath and spacecraft locations, See also, Notes, References, Bibliography, External links
American Revolution	Short description	The American Revolution (1765–1783) was an ideological and political movement in the Thirteen Colonies in what was then British America. The revolution culminated in the American Revolutionary War, which was launched on April 19, 1775, in the Battles of Lexington and Concord. Leaders of the American Revolution were colonial separatist leaders who, as British subjects, initially sought incremental levels of autonomy but came to embrace the cause of full independence and the necessity of prevailing in the Revolutionary War to obtain it. The Second Continental Congress, which represented the colonies and convened in present-day Independence Hall in Philadelphia, formed the Continental Army and appointed George Washington as its commander-in-chief in June 1775, and unanimously adopted the Declaration of Independence the following year, which inspired, formalized, and escalated the war. For most of the eight-year war, its outcome appeared uncertain. But in 1781, a decisive victory by Washington and the Continental Army in the Siege of Yorktown inspired King George III and the British to negotiate an end to colonial rule in the colonies and acknowledge their independence, which was codified in the Treaty of Paris in 1783, leading to the establishment of the sovereign United States of America. Discontent with colonial rule began shortly after the defeat of France in the French and Indian War in 1763. Even though the colonies had fought in and supported the war, British Parliament imposed new taxes to compensate for wartime costs and turned control of the colonies' western lands over to the British officials in Montreal. Representatives from several colonies convened the Stamp Act Congress in 1765; its "Declaration of Rights and Grievances" argued that taxation without representation violated their rights as Englishmen. In 1767, tensions flared again following British Parliament's passage of the Townshend Acts. In an effort to quell the mounting rebellion, King George III deployed British troops to Boston, where British troops killed protesters in the Boston Massacre on March 5, 1770. In 1772, anti-tax demonstrators destroyed the Royal Navy customs schooner Gaspee off present-day Warwick, Rhode Island. On December 16, 1773, in a seminal event in the American Revolution's escalation, Sons of Liberty activists wearing costumes of Native Americans instigated the Boston Tea Party, during which they boarded and dumped chests of tea owned by the British East India Company into Boston Harbor. London responded by closing Boston Harbor and enacting a series of punitive laws, which effectively ended self-government in Massachusetts but also served to expand and intensify the revolutionary cause. In late 1774, 12 of the Thirteen Colonies sent delegates to the First Continental Congress, which met inside Carpenters' Hall in Philadelphia; the Province of Georgia joined in 1775. The First Continental Congress began coordinating Patriot resistance through underground networks of committees. Following the Battles of Lexington and Concord, Washington and the Continental Army responded by surrounding Boston, forcing the British to withdraw by sea in March 1776, and leaving Patriots in control in every colony. In August 1775, King George III proclaimed Massachusetts to be in a state of open defiance and rebellion. In 1776, the Second Continental Congress began debating and deliberating on the Articles of Confederation, an effort to establish a self-governing rule of law in the Thirteen Colonies. On July 2, they passed the Lee Resolution, affirming their support for national independence, and on July 4, 1776, they unanimously adopted the Declaration of Independence, authored primarily by Thomas Jefferson, which embodied the political philosophies of liberalism and republicanism, rejected monarchy and aristocracy, and famously proclaimed that "all men are created equal". The Revolutionary War continued for another five years during which France ultimately entered the war, supporting the colonial cause of independence. On September 28, 1781, Washington, with support from Marquis de Lafayette, the French Army, and French Navy, led the Continental Army's most decisive victory, capturing roughly 7,500 British troops led by British general Charles Cornwallis during the Siege of Yorktown, leading to the collapse of King George's control of Parliament and consensus in Parliament that the war should be ended on American terms. On September 3, 1783, the British signed the Treaty of Paris, granting their former colonies nearly all the territory east of the Mississippi River and south of the Great Lakes. About 60,000 Loyalists migrated to other British territories in Canada and elsewhere, but the great majority remained in the United States. With its victory in the American Revolution, the United States became the first constitutional republic in world history founded on the consent of the governed and the rule of law.
American Revolution	Origins	Origins thumb\|A 1775 map of Eastern North America, including the Province of Quebec, the Thirteen Colonies on the Atlantic Coast, and the Indian Reserve as defined by the Royal Proclamation of 1763. The border between the red and pink areas represents the 1763 Proclamation line, and the orange area represents Spanish colonial claims. Under the British policy of salutary neglect, Britain traded with the colonies but otherwise mostly left them alone over the first 150 years of the colonies’ existence. The colonists became accustomed to running their own affairs, and they liked it. This British policy changed significantly after the French and Indian War, prompting the Thirteen Colonies to seek greater autonomy from Britain. After the Revolution, one colonist, Capt. Levi Preston, of Danvers, Massachusetts, was asked why the Americans rebelled against England, responded, "…we always had governed ourselves, and we always meant to. They didn’t mean we should."Fischer, David Hackett. Paul Revere’s Ride, 163-4, Oxford University Press, New York and Oxford, 1994..
American Revolution	1651–1763: Early seeds	1651–1763: Early seeds The Thirteen Colonies were established in the 17th century as part of the English Empire, and they formed part of the British Empire after the union of England and Scotland in 1707. The development of a unique American identity can be traced to the English Civil War (1642–1651) and its aftermath. The Puritan colonies of New England supported the Commonwealth government responsible for the execution of King Charles I. After the Stuart Restoration of 1660, Massachusetts did not recognize Charles II as the legitimate king for more than a year after his coronation. In King Philip's War (1675–1678), the New England colonies fought a handful of Native American tribes without military assistance from England, thereby contributing to the development of a uniquely American identity separate from that of the British people. In the 1680s, Charles and his brother, James II, attempted to bring New England under direct English control. The colonists fiercely opposed this, and the Crown nullified their colonial charters in response. In 1686, James finalized these efforts by consolidating the separate New England colonies along with New York and New Jersey into the Dominion of New England. Edmund Andros was appointed royal governor and tasked with governing the new Dominion under his direct rule. Colonial assemblies and town meetings were restricted, new taxes were levied, and rights were abridged. Dominion rule triggered bitter resentment throughout New England. When James tried to rule without Parliament, the English aristocracy removed him from power in the Glorious Revolution of 1688. This was followed by the 1689 Boston revolt, which overthrew Dominion rule. Colonial governments reasserted their control after the revolt. The new monarchs, William and Mary, granted new charters to the individual New England colonies, and local democratic self-government was restored. After the Glorious Revolution in 1688, the British Empire was a constitutional monarchy with sovereignty in the King-in-Parliament. Aristocrats inherited seats in the House of Lords, while the gentry and merchants controlled the elected House of Commons. The king ruled through cabinet ministers who depended on majority support in the Commons to govern effectively. British subjects on both sides of the Atlantic proudly claimed the unwritten British constitution, with its guarantees of the rights of Englishmen, protected personal liberty better than any other government. It served as the model for colonial governments. The Crown appointed a royal governor to exercise executive power. Property owners elected a colonial assembly with powers to legislate and levy taxes, but the British government reserved the right to veto colonial legislation. Radical Whig ideology profoundly influenced American political philosophy with its love of liberty and opposition to tyrannical government. With little industry except shipbuilding, the colonies exported agricultural products to Britain in return for manufactured goods. They also imported molasses, rum, and sugar from the British West Indies. The British government pursued a policy of mercantilism in order to grow its economic and political power. According to mercantilism, the colonies existed for the mother country's economic benefit, and the colonists' economic needs took second place. In 1651, Parliament passed the first in a series of Navigation Acts, which restricted colonial trade with foreign countries. The Thirteen Colonies could trade with the rest of the empire but only ship certain commodities like tobacco to Britain. Any European imports bound for British America had to first pass through an English port and pay customs duties. Other laws regulated colonial industries, such as the Wool Act 1698, the Hat Act 1731, and the Iron Act 1750.Max Savelle, Empires to Nations: Expansion in America, 1713–1824, p. 93 (1974) Colonial reactions to these policies were mixed. The Molasses Act 1733 placed a duty of six pence per gallon upon foreign molasses imported into the colonies. This act was particularly egregious to the New England colonists, who protested it as taxation without representation. The act increased the smuggling of foreign molasses, and the British government ceased enforcement efforts after the 1740s. On the other hand, certain merchants and local industries benefitted from the restrictions on foreign competition. The limits on foreign-built ships greatly benefitted the colonial shipbuilding industry, particularly in New England. Some argue that the economic impact was minimal on the colonists, but the political friction that the acts triggered was more serious, as the merchants most directly affected were also the most politically active. The British government lacked the resources and information needed to control the colonies. Instead, British officials negotiated and compromised with colonial leaders to gain compliance with imperial policies. The colonies defended themselves with colonial militias, and the British government rarely sent military forces to America before 1755. According to historian Robert Middlekauff, "Americans had become almost completely self-governing" before the American Revolution, a practice that was consistent with the British monarchy's practice of salutary neglect. During the French and Indian War (1754–1763), the British government fielded 45,000 soldiers, half British Regulars and half colonial volunteers. The colonies also contributed money to the war effort; however, two-fifths of this spending was reimbursed by the British government. Great Britain defeated France and acquired that nation's territory east of the Mississippi River. In early 1763, the Bute ministry decided to permanently garrison 10,000 soldiers in North America. This would allow approximately 1,500 politically well-connected British Army officers to remain on active duty with full pay (stationing a standing army in Great Britain during peacetime was politically unacceptable).Shy, Toward Lexington pp. 73–78 A standing army would provide defense against Native Americans in the west and foreign populations in newly acquired territories (the French in Canada and the Spanish in Florida). In addition, British soldiers could prevent white colonists from instigating conflict with Native Americans and help collect customs duties. Migration beyond the Appalachian Mountains increased after the French threat was removed, and Native Americans launched Pontiac's War (1763–1766) in response. The Grenville ministry issued the Royal Proclamation of 1763, designating the territory between the Appalachian Mountains and the Mississippi River as an Indian Reserve closed to white settlement. The Proclamation failed to stop westward migration while angering settlers, fur traders, and land speculators in the Thirteen Colonies.
American Revolution	1764–1766: Taxes imposed and withdrawn	1764–1766: Taxes imposed and withdrawn thumb\|Notice of the Stamp Act 1765 in a colonial newspaper George Grenville became prime minister in 1763, and "the need for money played a part in every important decision made by Grenville regarding the colonies—and for that matter by the ministries that followed up to 1776." The national debt had grown to £133 million with annual debt payments of £5 million (out of an £8 million annual budget). Stationing troops in North America on a permanent basis would cost another £360,000 a year. On a per capita basis, Americans only paid 1 shilling in taxes to the empire compared to 26 shillings paid by the English. Grenville believed that the colonies should help pay the troop costs. In 1764 Parliament passed the Sugar Act, decreasing the existing customs duties on sugar and molasses but providing stricter measures of enforcement and collection. That same year, Grenville proposed direct taxes on the colonies to raise revenue, but he delayed action to see whether the colonies would propose some way to raise the revenue themselves. Parliament passed the Stamp Act in March 1765, which imposed direct taxes on the colonies for the first time. All official documents, newspapers, almanacs, and pamphlets were required to have the stamps—even decks of playing cards. The colonists did not object that the taxes were high; they were actually low. They objected to their lack of representation in the Parliament, which gave them no voice concerning legislation that affected them, such as the tax, violating the unwritten English constitution. This grievance was summarized in the slogan "No taxation without representation". Shortly following adoption of the Stamp Act, the Sons of Liberty formed, and began using public demonstrations, boycotts, and threats of violence to ensure that the British tax laws became unenforceable. In Boston, the Sons of Liberty burned the records of the vice admiralty court and looted the home of chief justice Thomas Hutchinson. Several legislatures called for united action, and nine colonies sent delegates to the Stamp Act Congress in New York City in October. Moderates led by John Dickinson drew up a Declaration of Rights and Grievances stating that the colonists were equal to all other British citizens and that taxes passed without representation violated their rights as Englishmen, and Congress emphasized their determination by organizing a boycott on imports of all British merchandise.T.H. Breen, American Insurgents, American Patriots: The Revolution of the People (2010) pp. 81–82 American spokesmen such as Samuel Adams, James Otis, John Hancock, John Dickinson, Thomas Paine, and many others, rejected aristocracy and propounded "republicanism" as the political philosophy that was best suited to American conditions.Robert E. Shalhope, "Republicanism and early American historiography." William and Mary Quarterly (1982) 39#2 334–356. onlineHomer L. Calkin, "Pamphlets and public opinion during the American Revolution". Pennsylvania Magazine of History and Biography 64.1 (1940): 22–42. online The Parliament at Westminster saw itself as the supreme lawmaking authority throughout the Empire and thus entitled to levy any tax without colonial approval or even consultation.Middlekauff p. 62 They argued that the colonies were legally British corporations subordinate to the British Parliament.Lecky, William Edward Hartpole, A History of England in the Eighteenth Century (1882) pp. 297–298 Parliament insisted that the colonists effectively enjoyed a "virtual representation", as most British people did, since only a small minority of the British population were eligible to elect representatives to Parliament.Lecky, William Edward Hartpole, A History of England in the Eighteenth Century (1882) p. 173 However, Americans such as James Otis maintained that there was no one in Parliament responsible specifically to any colonial constituency, so they were not "virtually represented" by anyone in Parliament. The Rockingham government came to power in July 1765, and Parliament debated whether to repeal the stamp tax or to send an army to enforce it. Benjamin Franklin appeared before them to make the case for repeal, explaining that the colonies had spent heavily in manpower, money, and blood defending the empire, and that further taxes to pay for those wars were unjust and might bring about a rebellion. Parliament agreed and repealed the tax on February 21, 1766, but they insisted in the Declaratory Act of March 1766 that they retained full power to make laws for the colonies "in all cases whatsoever".Thomas P. Slaughter, "The Tax Man Cometh: Ideological Opposition to Internal Taxes, 1760–1790". William and Mary Quarterly (1984). 41 (4): 566–591. The repeal nonetheless caused widespread celebrations in the colonies.
American Revolution	1767–1773: Townshend Acts and the Tea Act	1767–1773: Townshend Acts and the Tea Act thumb\|Letter III of John Dickinson's Letters from a Farmer in Pennsylvania, published in the Pennsylvania Chronicle, December 1767 thumb\|On June 9, 1772, the Sons of Liberty burned HMS Gaspee, a British customs schooner in Narragansett Bay. thumb\|The December 16, 1773 Boston Tea Party, led by Samuel Adams and Sons of Liberty, has become a mainstay of American patriotic lore. In 1767, the British Parliament passed the Townshend Acts, which placed duties on several staple goods, including paper, glass, and tea, and established a Board of Customs in Boston to more rigorously execute trade regulations. Parliament's goal was not so much to collect revenue but to assert its authority over the colonies. The new taxes were enacted on the belief that Americans only objected to internal taxes and not to external taxes such as custom duties. However, in his widely read pamphlet, Letters from a Farmer in Pennsylvania, John Dickinson argued against the constitutionality of the acts because their purpose was to raise revenue and not to regulate trade.Melvin I. Urofsky and Paul Finkelman, A March of Liberty: A Constitutional History of the United States (Oxford UP, 2002) v. 1 p. 52. Colonists responded to the taxes by organizing new boycotts of British goods. These boycotts were less effective, however, as the goods taxed by the Townshend Acts were widely used. In February 1768, the Assembly of Massachusetts Bay Colony issued a circular letter to the other colonies urging them to coordinate resistance. The governor dissolved the assembly when it refused to rescind the letter. Meanwhile, a riot broke out in Boston in June 1768 over the seizure of the sloop Liberty, owned by John Hancock, for alleged smuggling. Customs officials were forced to flee, prompting the British to deploy troops to Boston. A Boston town meeting declared that no obedience was due to parliamentary laws and called for the convening of a convention. A convention assembled but only issued a mild protest before dissolving itself. In January 1769, Parliament responded to the unrest by reactivating the Treason Act 1543 which called for subjects outside the realm to face trials for treason in England. The governor of Massachusetts was instructed to collect evidence of said treason, and the threat caused widespread outrage, though it was not carried out. On March 5, 1770, a large crowd gathered around a group of British soldiers on a Boston street. The crowd grew threatening, throwing snowballs, rocks, and debris at them. One soldier was clubbed and fell.Hiller B. Zobel, The Boston Massacre (1996) There was no order to fire, but the soldiers panicked and fired into the crowd. They hit 11 people; three civilians died of wounds at the scene of the shooting, and two died shortly after. The event quickly came to be called the Boston Massacre. The soldiers were tried and acquitted (defended by John Adams), but the widespread descriptions soon began to turn colonial sentiment against the British. This accelerated the downward spiral in the relationship between Britain and the province of Massachusetts. A new ministry under Lord North came to power in 1770, and Parliament repealed most of the Townshend duties, except the tax on tea. This temporarily resolved the crisis, and the boycott of British goods largely ceased, with only the more radical patriots such as Samuel Adams continuing to agitate. In June 1772, American patriots, including John Brown, burned a British warship that had been vigorously enforcing unpopular trade regulations, in what became known as the Gaspee Affair. The affair was investigated for possible treason, but no action was taken. In 1773, private letters were published in which Massachusetts Governor Thomas Hutchinson claimed that the colonists could not enjoy all English liberties, and in which Lieutenant Governor Andrew Oliver called for the direct payment of colonial officials, which had been paid by local authorities. This would have reduced the influence of colonial representatives over their government. The letters' contents were used as evidence of a systematic plot against American rights, and discredited Hutchinson in the eyes of the people; the colonial Assembly petitioned for his recall. Benjamin Franklin, postmaster general for the colonies, acknowledged that he leaked the letters, which led to him being removed from his position. In Boston, Samuel Adams set about creating new Committees of Correspondence, which linked Patriots in all 13 colonies and eventually provided the framework for a rebel government. Virginia, the largest colony, set up its Committee of Correspondence in early 1773, on which Patrick Henry and Thomas Jefferson served.Greene and Pole (1994) chapters 22–24 A total of about 7,000 to 8,000 Patriots served on these Committees; Loyalists were excluded. The committees became the leaders of the American resistance to British actions, and later largely determined the war effort at the state and local level. When the First Continental Congress decided to boycott British products, the colonial and local Committees took charge, examining merchant records and publishing the names of merchants who attempted to defy the boycott by importing British goods.Mary Beth Norton et al., A People and a Nation (6th ed. 2001) vol 1 pp. 144–145 Meanwhile, Parliament passed the Tea Act lowering the price of taxed tea exported to the colonies, to help the British East India Company undersell smuggled untaxed Dutch tea. Special consignees were appointed to sell the tea to bypass colonial merchants. The act was opposed by those who resisted the taxes and also by smugglers who stood to lose business. In every colony demonstrators warned merchants not to bring in tea that included the hated new tax. In most instances, the consignees were forced by the Americans to resign and the tea was turned back, but Massachusetts governor Hutchinson refused to allow Boston merchants to give in to pressure. A town meeting in Boston determined that the tea would not be landed, and ignored a demand from the governor to disperse. On December 16, 1773, a group of men, led by Samuel Adams and dressed to evoke the appearance of Indigenous people, boarded the ships of the East India Company and dumped £10,000 worth of tea from their holds (approximately £636,000 in 2008) into Boston Harbor. Decades later, this event became known as the Boston Tea Party and remains a significant part of American patriotic lore.
American Revolution	1774–1775: Intolerable Acts	1774–1775: Intolerable Acts thumb\|A 1774 illustration from The London Magazine depicts Prime Minister Lord North, author of the Boston Port Act, forcing the Intolerable Acts down the throat of America, whose arms are restrained by Lord Chief Justice Mansfield with a tattered "Boston Petition" trampled on the ground beside her. Lord Sandwich pins down her feet and peers up her robes; behind them, Mother Britannia weeps while France and Spain look on. The British government responded by passing four laws that came to be known as the Intolerable Acts, further darkening colonial opinion towards England.Miller (1943) pp. 353–376 The first was the Massachusetts Government Act which altered the Massachusetts charter and restricted town meetings. The second was the Administration of Justice Act which ordered that all British soldiers to be tried were to be arraigned in Britain, not in the colonies. The third was the Boston Port Act, which closed the port of Boston until the British had been compensated for the tea lost in the Boston Tea Party. The fourth was the Quartering Act of 1774, which allowed royal governors to house British troops in the homes of citizens without permission of the owner.Carp, Defiance of the Patriots: The Boston Tea Party and the Making of America (2010) ch 9 In response, Massachusetts patriots issued the Suffolk Resolves and formed an alternative shadow government known as the Provincial Congress, which began training militia outside British-occupied Boston. In September 1774, the First Continental Congress convened, consisting of representatives from each colony, to serve as a vehicle for deliberation and collective action. During secret debates, conservative Joseph Galloway proposed the creation of a colonial Parliament that would be able to approve or disapprove acts of the British Parliament, but his idea was tabled in a vote of 6 to 5 and was subsequently removed from the record. Congress called for a boycott beginning on December 1, 1774, of all British goods; it was enforced by new local committees authorized by the Congress. It also began coordinating Patriot resistance by militias which existed in every colony and which had gained military experience in the French and Indian War. For the first time, the Patriots were armed and unified against Parliament.
American Revolution	Military hostilities begin	Military hostilities begin thumb\|Join, or Die, a political cartoon created in 1754 attributed to Benjamin Franklin, urged the Thirteen Colonies to unite. King George declared Massachusetts to be in a state of rebellion in February 1775Cogliano, Francis D. Revolutionary America, 1763–1815: A Political History. Routledge, 1999, p. 47. and the British garrison received orders to seize the rebels' weapons and arrest their leaders, leading to the Battles of Lexington and Concord on April 19, 1775. The Patriots assembled a militia 15,000 strong and laid siege to Boston, occupied by 6500 British soldiers. The Second Continental Congress convened in Philadelphia on June 14, 1775. The congress was divided on the best course of action. They authorized formation of the Continental Army and appointed George Washington as its commander-in-chief, and produced the Olive Branch Petition in which they attempted to come to an accord with King George. The king, however, issued a Proclamation of Rebellion which declared that the states were "in rebellion" and the members of Congress were traitors. The Battle of Bunker Hill followed on June 17, 1775. It was a British victory—but at a great cost: about 1,000 British casualties from a garrison of about 6,000, as compared to 500 American casualties from a much larger force.Harvey. "A few bloody noses" (2002) pp. 208–210Urban p. 74 As Benjamin Franklin wrote to Joseph Priestley in October 1775: In the winter of 1775, the Americans invaded northeastern Quebec under generals Benedict Arnold and Richard Montgomery, expecting to rally sympathetic colonists there. The attack was a failure; many Americans were killed, captured, or died of smallpox. In March 1776, aided by the fortification of Dorchester Heights with cannons recently captured at Fort Ticonderoga, the Continental Army led by George Washington forced the British to evacuate Boston. The revolutionaries now fully controlled all thirteen colonies and were ready to declare independence. There still were many Loyalists, but they were no longer in control anywhere by July 1776, and all of the Royal officials had fled.Miller (1948) p. 87

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