Today in the history of astronomy, a trailblazing mission on the Moon’s surface ends. Apollo 12 astronaut Pete Conrad stands next to Surveyor 3. Conrad and Alan Bean retrieved equipment from Surveyor to return to Earth for analysis. Credit: NASA On April 17, 1967, Surveyor 3 launched for the Moon. The second of NASA’s Surveyor spacecraft to soft land on the lunar surface, Surveyor 3 was commissioned with studying the Moon in preparation for the upcoming Apollo missions.  Surveyor 3 touched down on the Moon on April 20, though it wasn’t a smooth landing: When reflective rocks scrambled the lander’s radar, the engine didn’t cut at the correct altitude and the lander rebounded twice off the lunar surface. But despite this bumpy descent, Surveyor 3 was able to carry out its schedule of first-of-their-kind sampling experiments. The battery of tests were structured to prove that the lunar surface would be safe for Apollo astronauts to walk on – not to mention land a lunar module on.…