NASA on Tuesday announced a plan to develop a new deep space vehicle, one based on an earlier capsule concept, in order to send astronauts on expeditions to an asteroid, and then on to Mars.

The spaceship, known as the Multi-Purpose Crew Vehicle (MPCV), will be based on designs originally planned for the Orion spacecraft, NASA officials announced today (May 24). Orion was part of NASA's now-canceled Constellation program, which aimed to return astronauts to the moon by the 2020s. [Photos: NASA's MPCV for Deep Space Flights]

President Barack Obama shut down the Constellation program last year, tasking NASA instead with sending people to an asteroid by 2025, and then to aim for crewed Mars missions by the 2030s. Modifying the Orion capsule design — rather than drawing up plans for an entirely new spaceship — should help make that feasible, agency officials said.

"We are committed to human exploration beyond low-Earth orbit and look forward to developing the next generation of systems to take us there," NASA adminstrator Charlie Bolden said in a statement.

Meet the Multi-Purpose Crew Vehicle

Lockheed Martin Corp., NASA's prime contractor for Orion, will continue work to develop the MPCV spacecraft, agency officials said.

The spacecraft will carry four astronauts for three-week missions. The flights will end with a splashdown in the Pacific Ocean off the coast of California. The MPCV will have a pressurized volume of 690 cubic feet (20 cubic meters), with 316 cubic feet (9 cubic m) of habitable space, according to an official description. [Vote Now! The Best Spaceships of All Time]

It is designed to be 10 times safer during launch, re-entry and landing than its predecessor, the space shuttle, NASA officials said. While the MPCV will be NASA's primary vehicle for taking astronauts beyond low-Earth orbit, it may also be called upon to deliver cargo and crew to the International Space Station from time to time.

The MPCV will be capable of performing a variety of in-space activities, such as rendezvousing and docking with other craft. And astronauts aboard the MPCV will be able to perform spacewalks, officials said.

The MPCV will launch aboard a new heavy-lift rocket that NASA is also developing, agency officials said. Last year, Congress instructed the agency to have the spaceship and the launch vehicle ready to go by 2016, though NASA has said recently that it will probably need more time.

The Orion space capsule was originally designed to launch on NASA's Ares 1 rocket, with a larger heavy-lift rocket called Ares 5 planned to launch moon landers and other deep space flight hardware.

NASA in transition

Since the MPCV is based on existing designs, it won't require a radical rethink. And that thread of continuity may be welcome at NASA, which is in a period of dramatic transition.

The agency's space shuttle program, for example, will draw to a close this summer after three decades of service. The shuttle Atlantis' STS-135 mission in July will be the last for NASA's workhorse orbiter fleet, which will soon be put on display in museums around the country. [Most Memorable Space Shuttle Missions]

In the short term, NASA astronauts will get rides to the space station aboard Russian Soyuz vehicles. But over the long haul, Obama's vision calls for commercial American spaceships to provide this taxi service. NASA is working with and funding several private companies, such as California-based SpaceX, to help them develop these new craft.

That move is intended to free NASA up for more ambitious exploration efforts.

"The NASA Authorization Act lays out a clear path forward for us by handing off transportation to the International Space Station to our private sector partners, so we can focus on deep space exploration," Bolden said. "As we aggressively continue our work on a heavy lift launch vehicle, we are moving forward with an existing contract to keep development of our new crew vehicle on track."

*   Photos: NASA's Multi-Purpose Crew Vehicle for Deep Space Flights
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