The primary objective of Apollo 11 was to complete a national goal set by President John F. Kennedy on May 25, 1961: perform a crewed lunar landing and return to Earth. Additional flight objectives included scientific exploration by the lunar module, or LM, crew; deployment of a television camera to transmit signals to Earth; and deployment of a solar wind composition experiment, seismic experiment package and a Laser Ranging Retroreflector. During the exploration, the two astronauts were to gather samples of lunar-surface materials for return to Earth. Armstrong and Aldrin spent 21 hours, 36 minutes on the moon's surface. After a rest period that included seven hours of sleep, the ascent stage engine fired at 124 hours, 22 minutes. For more information, visit https://www.nasa.gov/mission_pages/apollo/missions/apollo11.html