solar orbit as of 2021, it may again be captured by Earth's gravity, but not at least until the 2040s. The S-IVBs used on later lunar missions were deliberately crashed into the Moon to create seismic events that would register on the seismometers left on the Moon and provide data about the Moon's structure. Spacecraft The Apollo 12 spacecraft consisted of Command Module 108 and Service Module 108 (together Command and Service Modules 108, or CSM–108), Lunar Module 6 (LM–6), a Launch Escape System (LES), and Spacecraft-Lunar Module Adapter 15 (SLA–15). The LES contained three rocket motors to propel the CM to safety in the event of an abort shortly after launch, while the SLA housed the LM and provided a structural connection between the Saturn V and the LM. The SLA was identical to Apollo 11's, while the LES differed only in the installation of a more reliable motor igniter. The CSM was given the call sign Yankee Clipper, while the LM had the call sign Intrepid. These sea-related names were selected by the all-Navy crew from several thousand proposed names submitted by employees of the prime contractors of the respective modules. George Glacken, a flight test engineer at North American Aviation, builder of the CSM, proposed Yankee Clipper as such ships had "majestically sailed the high seas with pride and prestige for a new America". Intrepid was from a suggestion by Robert Lambert, a planner at Grumman, builder of the LM, as evocative of "this nation's resolute determination for continued exploration of space, stressing our astronauts' fortitude and endurance of hardship". The differences between the CSM and LM of Apollo 11, and those of Apollo 12, were few and minor. A hydrogen separator was added to the CSM to stop the gas from entering the potable water tank—Apollo 11 had had one, though mounted on the water dispenser in the CM's cabin. Gaseous hydrogen in the water had given the Apollo 11 crew severe flatulence. Other changes included the strengthening of the recovery loop attached following splashdown, meaning that the swimmers recovering the CM would not have to attach an auxiliary loop. LM changes included a structural modification so that scientific experiment packages could be carried for deployment on the lunar surface. Two hammocks were added for greater comfort of the astronauts while resting on the Moon, and a color television camera substituted for the black and white