Ranger 7 - Mission Profile

Mission Profile

The Atlas 250D and Agena B 6009 boosters performed nominally at launch inserting the Agena and Ranger into a 192 km altitude Earth parking orbit. Half an hour after launch the second burn of the Agena engine injected the spacecraft into a lunar intercept trajectory. After separation from the Agena, the solar panels were deployed, attitude control activated, and spacecraft transmissions switched from the omniantenna to the high-gain antenna. The next day, 29 July, the planned mid-course maneuver was initiated at 10:27 UT, involving a short rocket burn. The only anomaly during flight was a brief loss of two-way lock on the spacecraft by the DSIF tracking station at Cape Kennedy following launch.

Ranger 7 reached the Moon on 31 July. 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 approximately 10°21′S 339°25′E / 10.35°S 339.42°E / -10.35; 339.42. (The impact site is listed as 10.63 S, 339.34 E 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.

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 - surely the reason the mission was successful. Since 1964 control rooms ceremonially open a container of peanuts for luck and tradition.