Orion MPCV

Orion has its roots in the Crew Exploration Vehicle concept from NASA''s Constellation program, first proposed in 2004 as part of the Vision for Space Exploration. When Constellation was cancelled in 2010, Orion survived as the Multi-Purpose Crew Vehicle, retained by Congress for deep-space missions.

The capsule is significantly larger than Apollo''s Command Module, designed to carry four astronauts for missions lasting up to 21 days. Its heat shield, the largest ever built for a human-rated spacecraft, must withstand reentry speeds of 25,000 mph when returning from the Moon -- far more severe than returns from low Earth orbit.

Orion completed its first test flight (EFT-1) in December 2014 aboard a Delta IV Heavy, reaching an altitude of 3,604 miles. The Artemis I mission in late 2022 was the first flight of the complete SLS/Orion system, sending an uncrewed Orion around the Moon. The Artemis II mission will carry four astronauts on a similar trajectory, making them the first humans to travel beyond low Earth orbit since Apollo 17 in 1972.