Smithsonian Air and Space Museum / The Lunar Lander, which consists of two parts, the descent stage at bottom, and the ascent stage on top. The most reliable part of the Apollo missions, Richard Erwin                                           the lander never suffered any failure that significantly impacted the mission. 6 of the descent stages remain on the surface of the moon, while most of 8/10/2009                                                  the ascent stages were allowed to crash on the moon after delivering their cargos of men and equipment to the orbiter. 15 landers were built, each                                                                     designed to carry a crew of two to the moon's surface. In April, 1970, the seventh module saved the lives of the crew of Apollo 13 when an oxygen                                                                     tank exploded on the way to the moon. The module served as a haven for the astronauts on the way back to Earth, as well as providing extra thrust                                                                     in rounding the moon and re-charging the batteries in the command module used for re-entry.