page_title: Ranger 7
section_title: Mission profile
hierarchical_section_title: Ranger 7 / Mission profile
caption_attribution_description: English: This is the first image of the Moon from a US spacecraft which was taken by Ranger 7 on July 31, 1964 at 13:09 UTC, about 17 minutes before impact. The large crater at center right is Alphonsus.
context_page_description: Ranger 7 was the first space probe of the United States to successfully transmit close images of the lunar surface back to Earth. It was also the first completely successful flight of the Ranger program. 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 and four narrow-angle – 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.
context_section_description: On July 6, Ranger 7 completed its ground testing and was stacked atop the booster. On July 9, a NASA committee met and deemed the booster and spacecraft fully ready for launch, which was targeted for the 27th.
  The first countdown on July 27 failed due to a defective battery in the Atlas and a problem with the ground guidance equipment. The next day, all went smoothly and Ranger 7 lifted off from LC-12 at 12:50 PM EST. The weather was clear and cloudless on this launch and Atlas staging was observed by tracking cameras. The expected propellant cloud enveloped the booster, but no anomalous events occurred this time. Thirty minutes after liftoff, the Agena restarted to boost Ranger 7 on a trajectory towards the Moon.
  The flight trajectory for Ranger 7 was quite accurate, but a short midcourse correction would still be needed to ensure impact in the Sea of Storms instead of the far side of the Moon, which was carried out early on the morning of July 29. The warmup period for the TV cameras would be performed earlier and made shorter than on Ranger 6. Out of fear of jeopardizing the mission, ground controllers decided that the probe's orientation was acceptable enough and they would not risk maneuvering with the attitude control thrusters to get into a better angle. At 6:09 AM PDT, the first video imagery reached Earth.
  As Ranger 7 sped towards the surface of the Moon, TV camera performance remained normal. Images of the cratered lunar surface continued to filter back to JPL headquarters in Pasadena, California and finally, at 6:25, impact occurred and all signals from the probe ceased. In the JPL control room, there was "rapturous celebration". Ranger 7 had delivered the first close-distance imagery of the lunar surface and "more than anything, even the manned Mercury missions, had at last undone the sting Americans felt at Sputnik 1's launch".
  The photographs returned from the probe found that the Moon was most likely "very craggy and rocky with debris everywhere". After speaking to the media, NASA officials were peppered with the obvious question – did the Moon have a surface solid enough that humans could safely land on it? Geologist Gerard Kuiper replied that, judging by the images, it seemed likely that at least some of the Moon was smooth enough to land a spacecraft on. However, the actual hardness of the surface couldn't be determined with certainty until a soft landing was made. Nonetheless, Ranger 7's images did seem to suggest that it was solid enough.
  Ranger 7 reached the Moon on July 31. The F-channel began its one-minute warm-up 18 minutes before impact. The first image was taken at 13:08:45 UT at an altitude of 2110 km. Transmission of 4,308 photographs of excellent quality occurred over the final 17 minutes of flight. The final image taken before impact has a resolution of 0.5 meters. The spacecraft encountered the lunar surface in direct motion along a hyperbolic trajectory, with an incoming asymptotic direction at an angle of -5.57 degrees from the lunar equator. The orbit plane was inclined 26.84 degrees to the lunar equator. After 68.6 hours of flight, Ranger 7 impacted in an area between Mare Nubium and Oceanus Procellarum (subsequently named Mare Cognitum) at 10.6340°S 20.6771°W. (The impact site is listed as 10.63 S, 20.66 W in the initial report "Ranger 7 Photographs of the Moon".) Impact occurred at 13:25:48.82 UT at a velocity of 2.62 km/s. The spacecraft performance was excellent and the success of the mission finally brought a turnaround in NASA's fortunes after the endless string of lunar probe failures since 1958.
  Ranger 7 is credited for beginning the "peanut" tradition at NASA command stations. On the success of Ranger 7, someone in the control room was noticed eating peanuts. Since 1964 control rooms ceremonially open a container of peanuts for luck and tradition.
caption: First image of the Moon taken by a U.S. spacecraft. The large crater at center right is Alphonsus
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