By Irene Klotz
Cape Canaveral, Florida
The shuttle is entering its final days
A dramatic showdown that threatened to remove the US and its partners from the International Space Station (ISS) appears to be over, as lawmakers eased a trade ban that prevents Nasa from buying Russian space transportation services.
The United States is giving up its own fleet of spaceships in 2010 due to safety and cost issues.
Vehicles to replace the space shuttles are not expected until 2015 at the earliest.
In addition to ferrying astronauts to and from the orbital complex, Russian Soyuz capsules serve as lifeboats in case the crew has to come home in an emergency.
Nasa has an agreement with Russia to provide space transport and other services through 2011.
But with a three-year lead time to manufacture the ships, the agency has been pushing for a new contract to assure uninterrupted access to the station, particularly with the shuttle's retirement looming.
Under international agreements, Nasa also is responsible for transportation for its partners in the space station project, which include Europe, Japan and Canada.
But the agency has faced formidable political challenges. Current laws prohibit Nasa from spending tax dollars on Russia space services and technology due to concerns about weapons proliferation to Iran and North Korea.
Congress approved a six-year exemption in 2005, but Russia's ongoing conflict with Georgia, a US ally, threatened Nasa's ability to wrangle additional waivers.
Agency administrator Michael Griffin has said the exemption needs to be approved before the end of the year to have Soyuz vehicles available when the current contract expires.
Earlier this month, Dr Griffin wrote an email to top managers, which was leaked to the media, saying the political hurdles seemed insurmountable and it appeared that the United States would have to temporarily abandon the station.
But late Wednesday, the US House of Representatives slipped a provision into an overall spending bill that allows Nasa to continue purchasing spacecraft from Russia. The Senate passed a similar bill on 21 September.
"There's a least one more step before we will be given actual relief (on the trade ban)," space station programme manager Mike Suffredini told reporters on Thursday.
"We're right now in the throes of trying to see if we can reach an agreement (with the Russians), but it won't matter if we don't have (the exemption)."
At a gala marking Nasa's 50th anniversary on Wednesday night, Dr Griffin sardonically noted that permission to spend US tax dollars for Russian rides to the US-built space station "is a victory because all of the other outcomes are worse. That's the situation we find ourselves."
Nasa and its partners have spent $100bn building the orbital complex, which is expected to be completed in 2010.
The agency next month plans to fly equipment that will support an expanded six-person crew. Managers are targeting the launch for 16 November, following an October space shuttle mission to service the Hubble Space Telescope.
That flight was pushed back from 10 October to 14 October to make up time lost when the Johnson Space Center was shut down due to Hurricane Ike.
The Hubble crew and its flight team lost six days of training that Nasa decided was too important to miss.
Nasa has just 10 flights remaining before the shuttles are permanently retired, though some legislators, including Republican presidential hopeful John McCain, have called for additional flights to narrow the period of time when the US will be without its own access to space.
Nasa is resisting the move, saying it needs the money for the shuttle replacement, a rocket-capsule combination known as Ares-Orion.
"We started shutting down the shuttle four years ago," noted Nasa deputy associate administrator Wayne Hale in his blog.
"That horse has left the barn."