Free Astronomy Magazine May-June 2019

23 MAY-JUNE 2019 ASTRONAUTICS essary to fill the gaps and make follow-up studies of the most in- teresting sites. Lunar Orbiter 1 was launched on 10 August 1966 and entered lunar orbit on 14 August. In mapping mode, it had to take four narrow frames for each wide-angle image, so that the sequences contiguously covered the surface − but a motion compensator malfunction blurred pleting its main mission. The space- craft transmitted the telemetry for another two months to assess the degradation of its systems, then was deorbited to clear the path for its successor, which entered service on 18 November. In addition to in- specting the eleven remaining can- didate sites, Lunar Orbiter 2 was able to photograph a number of secondary sites that, while not im- the images taken up-close. Al- though the flight controllers con- sidered an increase of the perilune to reduce blurring and map the en- tire Apollo destination area with a resolution of about 30 meters, it was decided to document the planned sites at a lower resolution. On August 29, Lunar Orbiter 1 pho- tographed the ninth potential landing site on its target list, com-