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
Huygens (spacecraft) Huygens (spacecraft) Huygens was an atmospheric entry probe that landed successfully on Saturn's moon Titan in 2005. Built and operated by the European Space Agency (ESA), it was part of the "Cassini–Huygens" mission and became the first spacecraft ever to land on Titan and the farthest landing from Earth a spacecraft has ever made. The probe was named after the Dutch 17th-century astronomer Christiaan Huygens, who discovered Titan in 1655. The combined "Cassini–Huygens" spacecraft was launched from Earth on October 15, 1997. "Huygens" separated from the "Cassini" orbiter on December 25, 2004, and landed on Titan on January 14, 2005