the mission by noting that, aside from the cameras, Ranger 6 and its Atlas-Agena booster had both functioned "extremely well". Ranger 6 was launched into an Earth parking orbit and injected on a lunar trajectory by a second Agena burn. The midcourse trajectory correction was accomplished early in the flight by ground control. On February 2, 1964, 65.5 hours after launch, Ranger 6 impacted the Moon on the eastern edge of Mare Tranquillitatis (Sea of Tranquility in English). The orientation of the spacecraft to the surface during descent was correct, but no video signal was received and no camera data obtained. A review board determined the most likely cause of failure was due to an arc-over in the TV power system when it inadvertently turned on for 67 seconds approximately 2 minutes after launch during the period of booster-engine separation. This fourth American attempt at lunar impact was the closest success. The spacecraft, the first Block III type vehicle with a suite of six TV cameras, was sterilized to avoid contaminating the lunar surface. The series would also serve as a test bed for future interplanetary spacecraft by deploying systems (such as solar panels) that could be used for more ambitious missions. The Block III spacecraft carried a 173-kilogram TV unit (replacing the impact capsule carried on the Block II Ranger spacecraft). The six cameras included two full-scan and four partial-scan cameras. Ranger 6 flew to the Moon successfully and impacted precisely on schedule at 09:24:32 GMT on February 2. Unfortunately, the power supply for the TV camera package had short-circuited three days previously during Atlas booster separation and left the system inoperable. The cameras were to have transmitted high-resolution photos of the lunar approach from 1448 kilometers to 6.4 kilometers range in support of Project Apollo. Impact coordinates were 9°24' north latitude and 21°30' east longitude. Footnotes See also Ranger program Timeline of Solar System exploration List of artificial objects on the Moon References External links Lunar impact: A history of Project Ranger (PDF) 1977 6 Spacecraft launched in 1964 Spacecraft that impacted the Moon Impactor spacecraft 1964 on the Moon