The Apollo Vehicle was the spacecraft used by the United States in the Apollo program to land astronauts on the Moon. The Lunar Excursion Module (LEM), also known as the Eagle, was the spacecraft that carried two astronauts from the Command/Service Module (CSM) to the lunar surface and back. It was the first manned spacecraft to land on the Moon and was designed to be used for a single mission. The LEM was powered by four rocket engines and had a crew of two astronauts.