The Constellation programme: gone in name only. Credit: MSFC/NASA

NASA is caught between President Barack Obama and Congress, and Republican gains in the midterm elections could prolong the agony. In February, Obama called for an end to the Constellation programme to take astronauts to the Moon and Mars after a review called it underfunded and overambitious. The administration wants to invest in new technology and private spaceflight.

Congress baulked, and on 29 September passed an act requesting funds for projects initiated under Constellation and granting less than half of the administration's request for private spaceflight. With Congress now in recess and unable to allocate funds, NASA is funded at current levels and cannot change course.

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"It has to keep spending on programmes that it's going to kill, and can't start new programmes that it wants to," says Keith Cowing, editor-in-chief of the website NASA Watch.

If the Democrats retain control of the Senate and House of Representatives, they will probably quickly pass an appropriations bill to allocate the money, says John Logsdon, former director of the Space Policy Institute at the George Washington University in Washington DC. But if the Republicans prevail, they may defer negotiations until January, when they would take over the appropriations subcommittee.

Appropriators must also find US$500 million for a key project in the act: an extra flight for the retiring space shuttle. The money could come from NASA's science allocation, but the administration would object to that, says Logsdon.

For Cowing, competing interests could spell a troubled future for the space agency. "How can NASA progress if it's pulled in ten different directions?" he asks.