I’ve told you before about the ongoing effort to reprocess (and as a result, to enhance) old data tapes from the Lunar Orbiter program of 1966-1967. Well, if you were curious about what the original spacecraft looked like, here’s an engineering model of the orbiters hanging up in the National Air and Space Museum in Washington D.C.:
The driving mission of the Lunar Orbiter project was to map the Moon in preparation for the Apollo landings. The first three spacecraft were dedicated to photographing potential landing sites, but they did their job so well that the last two missions could be used for broader scientific missions, and so they were flown in polar orbits. Since all five missions were successful, this resulted in photographing 99% of the Moon’s surface at a resolution of 60 m or better.
The imaging technology of the time was based on film scanning — photographs were taken on film, the film was processed in real-time onboard the spacecraft, and then the film was scanned to get its data to the ground. As a result, once each spacecraft ran out of film, it could no longer return much scientific information. To avoid a variety of hazards to the upcoming Apollo missions, the orbiters were commanded to crash into the moon once their useful lives were over.