Apollo 15 15 separated from the booster, the S-IVB maneuvered away, and would impact the Moon about an hour after the crewed spacecraft entered lunar orbit, though due to an error the impact was away from the intended target. The booster's impact was detected by the seismometers left on the Moon by Apollo 12 and Apollo 14, providing useful scientific data. There was a malfunctioning light on the craft's service propulsion system (SPS); after considerable troubleshooting, the astronauts did a test burn of the system that also served as a midcourse correction. This occurred about 028:40:00 into the mission. Fearing that the
Apollo 12 control assumed by Conrad during the final few hundred feet of descent. Unlike Apollo 11, where Neil Armstrong had to use the manual control to direct his lander downrange of the computer's target which was strewn with boulders, Apollo 12 succeeded in landing at its intended target – within walking distance of the "Surveyor 3" probe, which had landed on the Moon in April 1967. This was the first – and, to date, only – occasion in which humans have "caught up" to a probe sent to land on another world. Conrad actually landed "Intrepid" short of "Pete's Parking Lot",