Orion is a spacecraft design which is under development by NASA. Each Orion spacecraft will carry a crew of four to six astronauts. This new NASA spaceship will be launched by the Ares I, which is a launching booster also under development. Both Orion and Ares I are parts of NASA's Constellation Program, a space project to send human explorers to the Moon by 2020, and then onward to Mars and perhaps other destinations in the Solar System. On August 31, 2006, Lockheed Martin was granted the contract by NASA to design, develop, and build Orion.
Orion spacecraft will be launched from Launch Complex 39 at Kennedy Space Center, the same launch complex that currently launches the space shuttle. While shuttle operations continue from launch pad 39A, 39B is being readied for Ares launches. NASA will use Orion spacecraft for its human spaceflight missions after the last shuttle orbiter is retired in 2010. The first crewed Orion flight is anticipated in 2015. Subsequent flights will visit the International Space Station. If commercial orbital transportation services are unavailable, Orion will handle logistic flights to the Station. After that, Orion is to become a key component of human missions to the Moon and Mars.
On January 14, 2004, President George W. Bush announced the Orion spacecraft, known then as the Crew Exploration Vehicle, as part of the Vision for Space Exploration. The proposal to create the Orion spacecraft was partly a reaction to the Space Shuttle Columbia accident, the subsequent findings and report by the Columbia Accident Investigation Board (CAIB), and the White House's review of the American space program. The Orion spacecraft effectively replaced the conceptual Orbital Space Plane (OSP), which itself was proposed after the failure of the Lockheed Martin X-33 program to produce a replacement for the space shuttle.
The Crew and Service Module stack of the Orion spacecraft is composed of two main parts: a conical Crew Module, and a cylindrical Service Module that holds the spacecraft's propulsion system and expendable supplies. Both are based substantially on the Apollo Command and Service Modules (Apollo CSM) flown between 1967 and 1975, but include advances derived from the space shuttle program. "Going with known technology and known solutions lowers the risk," according to Neil Woodward, director of the integration office in the Exploration Systems Mission Directorate.