The Orion Multi-Purpose Crew Vehicle (Orion MPCV) is an American spacecraft intended to carry a crew of four astronauts to destinations at or beyond low Earth orbit. Currently under development by NASA for launch on the Space Launch System, Orion is intended to facilitate human exploration of asteroids and of Mars, as well as to provide a means of delivering or retrieving crew or supplies from the ISS if needed.

On January 14, 2004, U.S. President George W. Bush announced the Crew Exploration Vehicle (CEV) as part of the Vision for Space Exploration. As the Vision for Space Exploration was developed into the Constellation program under NASA administrator Sean O'Keefe, the Crew Exploration Vehicle was renamed the Orion Crew Exploration Vehicle, after the constellation of the same name. Constellation proposed using the Orion CEV in both crew and cargo variants to support the International Space Station and as a crew vehicle for a return to the Moon. The Orion CEV design consisted of two main parts: a conical crew module (CM) and a cylindrical service module (SM) holding the spacecraft's propulsion system and expendable supplies. Both were based substantially on the Apollo command and service modules flown between 1967 and 1975. The Orion CEV was to be launched on an Ares I rocket to low Earth orbit, where it would rendezvous with the Altair lunar surface access module launched on a heavy-lift Ares V launch vehicle for lunar missions.

On May 7, 2009 the Obama administration enlisted the Augustine Commission to perform a full independent review of the ongoing NASA space exploration program. The commission found the then current Constellation Program to be woefully underbudgeted, behind schedule by 4 years or more in several essential components, with significant cost overruns, and unlikely to be capable of meeting any of its current scheduled goals under its current budget. As a consequence, the commission recommended a significant re-allocation of goals and resources. As one of the many outcomes based on these recommendations, on October 11, 2010, the Constellation program was cancelled, ending development of the Altair, Ares I, and Ares V. The Orion Crew Exploration Vehicle survived the cancellation and was renamed the Multi-Purpose Crew Vehicle (MPCV), to be launched on the Space Launch System.

Through the program restructuring from Constellation to post-Constellation, the Orion development program moved from the development of three different versions of the Orion capsule, each for a different task, to the development of a single version capable of performing multiple tasks. On October 30, 2014, the somewhat redesigned Multi-Purpose spacecraft completed its first Flight Readiness Review, allowing the vehicle to be integrated with the Delta IV rocket and readied for launch. On December 5, 2014 it was successfully launched into space and retrieved at sea after splashdown on the Exploration Flight Test 1, marking NASA's re-entry into the business of designing and producing new crewed spacecraft.

ORION MPCV SPECIFICATIONS

First flight: 5-Dec-2014; first manned flight planned no later than April 2023
Principal uses: beyond LEO spacecraft
Cost: US$6.77 billion through first crewed mission (2015 estimate)
Crew size: 2 to 6
Endurance: 21 days active crew time, plus 6 months quiescent
Overall length: 8 m (without escape tower)
Principal diameter: 5.0 m
Habitable volume: 8.95 m³
Launch mass: 35,385 kg
Injected mass: 26,520 kg
Total spacecraft delta v: 1,338 m/s

LAUNCH ABORT SYSTEM
Dry mass: 5,044 kg
Launch mass: 7,643 kg

CREW MODULE
Crew size: 2 to 6
Length: 3.3 m
Maximum diameter: 5.0 m
Pressurized volume: 19.56 m³
Habitable volume: 8.95 m³
RCS engine thrust: each 712 N vac
Dry mass: 10,159 kg
Propellant mass: 168 kg
Oxygen/nitrogen/water: 60 kg
Landing mass: 9,299 kg
Launch mass: 10,387 kg
Return payload: 100 kg
Environment: oxygen/nitrogen at 1 atm
Contractor: Lockheed Martin

SERVICE MODULE
Dry mass: 6,185 kg
Launch mass: 15,461 kg
Contractor: Airbus Defense and Space

ORION-TO-STAGE ADAPTER
Jettisoned fairings: 1,383 kg
Spacecraft adapter: 510 kg