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 6 spacecraft only entered the atmosphere at a speed of instead of the planned of a lunar return. However, this had been demonstrated on Apollo 4. Ten hours after launch, it landed from the planned touchdown point in the North Pacific Ocean north of Hawaii, and was lifted on board the USS "Okinawa". The S-IVB's orbit decayed three weeks later, and it reentered the atmosphere on April 25, 1968. Although Apollo 6 did not reach full translunar velocities in either direction, it was considered successful enough to fly astronauts on the next Saturn V, which in addition was tasked to send