page_title: Ranger 8
section_title: Mission profile
hierarchical_section_title: Ranger 8 / Mission profile
caption_attribution_description: Italiano: Lancio di Ranger 8
context_page_description: Ranger 8 was a lunar probe in the Ranger program, a robotic spacecraft series launched by NASA in the early-to-mid-1960s to obtain the first close-up images of the Moon's surface. These pictures helped select landing sites for Apollo missions and were used for scientific study. During its 1965 mission, Ranger 8 transmitted 7,137 lunar surface photographs before it crashed into the Moon as planned. This was the second successful mission in the Ranger series, following Ranger 7. Ranger 8's design and purpose were very similar to those of Ranger 7. It had six television vidicon cameras: two full-scan and four partial-scan. Its sole purpose was to document the Moon's surface.
context_section_description: The Atlas 196D and Agena B 6006 boosters performed nominally, injecting the Agena and Ranger 8 into an Earth parking orbit at 185 km altitude after launch. Fourteen minutes later a 90-second burn of the Agena put the spacecraft into lunar transfer trajectory, and several minutes later the Ranger and Agena separated. The Ranger solar panels were deployed, attitude control activated, and spacecraft transmissions switched from the omniantenna to the high-gain antenna by 21:30 UT. On February 18, at a distance of 160,000 km from Earth, the planned mid-course maneuver took place, involving reorientation and a 59-second rocket burn. During the 27-minute maneuver, spacecraft transmitter power dropped severely, so that lock was lost on all telemetry channels. This continued intermittently until the rocket burn ended, at which time power returned to normal. The telemetry dropout had no serious effects on the mission. A planned terminal sequence to point the cameras more in the direction of flight just before reaching the Moon was cancelled to allow the cameras to cover a greater area of the Moon's surface. 
  Ranger 8 reached the Moon on February 20, 1965. The first image was taken at 9:34:32 UT at an altitude of 2510 km. Transmission of 7,137 photographs of good quality occurred over the final 23 minutes of flight. The final image taken before impact has a resolution of 1.5 meters. The spacecraft encountered the lunar surface in a direct hyperbolic trajectory, with incoming asymptotic direction at an angle of −13.6 degrees from the lunar equator. The orbit plane was inclined 16.5 degrees to the lunar equator. After 64.9 hours of flight, impact occurred at 09:57:36.756 UT on February 20, 1965, in Mare Tranquillitatis at approximately 2.67° N, 24.65° E. (The impact site is listed as about 2.72° N, 24.61° E in the initial report "Ranger 8 Photographs of the Moon".) Impact velocity was slightly less than 2.68 km/s, approximately 6,000 mph. The spacecraft performance was excellent.
  The impact crater of Ranger 8, approximately 13.5 m wide, was later photographed by Lunar Orbiter 4.
caption: Launch of Ranger 8 with Atlas-Agena rocket.
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