New NASA rocket for mission to Mars

The long-awaited space launch system will be "the most powerful rocket in history", according to Florida senator Bill Nelson, a former space shuttle astronaut.

But although NASA plans to launch unmanned test flights by 2017, it has laid out no timetable for its stated goals of landing on an asteroid, reaching Mars, or sending astronauts into deep space for the first time since the Apollo era of the late 1970s.

The announcement, by members of the US Senate's Commerce, Science and Transportation committee, returns NASA to the business of human spaceflight following the retirement of the space shuttle fleet in July.

"This allows NASA to get out beyond lower earth orbit and start to explore the heavens, which is the job NASA has always been tasked to do," Mr Nelson said.

"In the bosom of America there is a yearning for us to explore."

Funding for the project, which blends existing Apollo and space shuttle technology with development of a new crew transportation system, must be approved in Congress, where it faces a bumpy ride.

Mr Nelson and his fellow advocates did not deliver a long-term estimate, but it could reach $US62.5 billion ($A61 billion) by 2025, according to experts who studied leaked NASA budget documents.

But he said that the government's financial commitment over the next five to six years would be about $US18 billion.

NASA hopes the project will now allow it to rehire many of the thousands of workers laid off at the end of the 30-year space shuttle program.