Ranger 7, an unmanned US lunar probe, takes the first close-up images of the moon—4,308 in total—before it impacts with the lunar surface northwest of the Sea of Clouds. The images were 1,000 times as clear as anything ever seen through earth-bound telescopes.
The National Aeronautics and Space Administration (NASA) had attempted a similar mission earlier in the year—Ranger 6—but the probe’s cameras had failed as it descended to the lunar surface. Launched on July 28, 1964, Ranger 7 was designed to achieve a lunar-impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact. The spacecraft carried six television vidicon cameras – two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P) – to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality video pictures. Ranger 7 transmitted over 4,300 photographs during the final 17 minutes of its flight. After 68.6 hours of flight, the spacecraft landed between Mare Nubium and Oceanus Procellarum. This landing site was later named Mare Cognitum. The velocity at impact was 1.62 miles per second, and the performance of the spacecraft exceeded hopes. No other experiments were carried on the spacecraft.
Along with Rangers 8 and 9, its pictures helped the United States plan the excursions for the Apollo program, which saw astronauts land on the moon between 1969 and 1972.
The spacecraft came at a very early time in space exploration, when engineers were still learning the fundamentals about how to keep a machine working in space. As such, Ranger 7 followed six failed missions in its own program over several years. It made the first pictures extra-special.In July 1969, two Americans walked on the moon in the first Apollo Programme lunar landing mission.
History
