NASA's Multi-Purpose Crew Vehicle on a future mission of human exploration. On long missions the MPCV would join with a larger crew habitation module. Image Credit/NASA

The four person Orion spacecraft, once part of the Constellation program, will emerge as a center piece of U. S. plans to resume the exploration of deep space with astronauts,  NASA  Administrator Charles Bolden and other agency officials announced on Tuesday.

The strategy will build on the nearly $5 billion NASA has already invested in efforts to develop Orion as part of the Bush administration’s goals of launching explorers to the moon and Mars.

The MPCV will play a similar role, though the Obama administration’s goals are less specific. Last year, the president tasked NASA with reaching a near Earth asteroid with explorers by 2025 and launching a mission to the environs of Mars a decade or so later. Eventually, explorers will land on the Red Planet, Obama 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,” Bolden said Tuesday.

The agency has yet to settle on a strategy for a new heavy lift rocket that would launch the largely reusable MPCV, but a decision and announcement are  likely by early summer,  Doug Cooke, NASA’s director of exploration systems, told a news briefing.

The MPCV and heavy lift rocket, or Space Launch System, are key elements of the 2010 NASA Authorization Act that was passed by Congress last year and signed into law by President Obama in October. The legislation directed NASA to make use of past investments in Orion, while leveraging the propulsion elements of the space shuttle and the proposed Constellation family of Ares rockets.

Congress reached a compromise with the White House over plans for NASA to foster the development of commercial space transportation services that will replace the shuttle as the means for carrying astronauts to and from the International Space Station.

Lockheed Martin, which was awarded the 2006 NASA contract to develop Orion, will lead the MPCV work as well, Cooke said.

The agency reached its decision on the MPCV after considering other industry alternatives that included using composite structures and another type of crew escape strategy. The escape system developed by Lockheed Martin for Orion is a critical part of a goal to make the MPCV at least 10 times safer than the space shuttle, Cooke said.

NASA will retire the space shuttle fleet in July after 31 years of operations and 135 flights, two of them fatal to 14 astronauts.

NASA and Lockheed Martin carry out a successful test of the Orion capsule's crew escape system at White Sands, N. M. Photo Credit/NASA photo

Recently, NASA’s Congressional oversight committees have expressed frustration with what lawmakers characterized as the agency’s lack of progress in carrying out the Authorization Act blueprint. The legislation calls on NASA to have the MPCV and Space Launch System ready for operations by late 2016.

Earlier this year, NASA informed lawmakers it could not make that date with the funding envisioned. And it questioned the initial need for a rocket as large as Congress requested.

Cooke did not say when the MPCV and new SLS would be ready for their initial missions. The milestone will be paced by future funding levels, he said.

Both the space agency and Lockheed Martin said Tuesday to intend to pursue new measures to constrain development and management costs.

In previous statements, Lockheed Martin said it would like to launch an unmanned test of the MPCV in 2013.

Under the direction of Congress, the MPCV and new heavy lifter could also deliver astronauts to the International Space Station, if plans for commercial transportation services fall behind schedule.

Though a part of the MPCV strategy, Cooke said space station missions would not represent an efficient use of the new capsule and rocket.

The first commercial launches of U. S. astronauts to the station are envisioned for around 2015. Until then, NASA will pay the Russians to launch U. S. astronauts to the orbiting science laboratory aboard Soyuz rockets.

Former president George Bush proposed the Constellation program in the aftermath of the 2003 shuttle Columbia tragedy. In 2004, he directed NASA to return explorers to the moon by 2020 and establish a human base.

Soon after taking office, Obama appointed a White House commission to re-examine Constellation. The Augustine Committee concluded the project was behind schedule and on a financially unsustainable course. The commission suggested NASA consider a range of deep space missions rather than committing to further exploration of the moon.