The Surveyor program was originally the grand plan for lunar exploration in the 1960's until Kennedy decided to prioritize putting humans on the moon. Instead the Surveyor missions, developed and operated by JPL, became precursor missions to test technologies and measure the lunar surface to make sure humans could safely land on the moon.
After recent lunar landing missions experienced various levels of success, I was really curious as to how the landing guidance operated on a 60 year old spacecraft without fully digital computers. Using 4 radar beams the spacecraft's analogue guidance system was able to descend under control and cancel its velocity for the soft landing.

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