The space shuttle is due for retirement in 2010, and NASA's next spaceship, Orion, won't be available until at least 2015. That will leave a five-year gap during which NASA astronauts and space-station cargo will be grounded unless they find other ways to get to orbit. In the past, NASA has cadged rides off its former arch-rival, the Russian Federal Space Agency, and its Soyuz (for astronauts) and Progress (for cargo) spacecraft. But relations between the U.S. and Russia are cooling, raising the very real prospect that Congress will forbid NASA to buy spaceflights from Russia. NASA has stepped up its support of two U.S. companies, Space Exploration Technologies (SpaceX) and Orbital Sciences Corporation, that hope to have unmanned cargo spaceships ready for launch by 2010. (See details below.) Even if these companies succeed, NASA will still have to rely on Soyuz for manned flights. But maybe not for long. Here's a roundup of seven rides to low Earth orbit besides the space shuttle and Soyuz that could be available for space-station flights.
2003 | SHENZOU
China National Space Administration
China became Earth's third space-faring nation with this vehicle's first launch in 2003. Since then, these single-use craft, loosely based on Soyuz and boosted by China's Long March 2F rockets, have been flying taikonauts to orbit once every two or three years, making the Shenzhou the only vehicle besides Soyuz and the shuttle that could currently fly astronauts to the International Space Station. NASA and its Chinese counterpart have so far shown no signs of cooperating, but that could change.
2009 | H-II TRANSFER VEHICLE
Japan Aerospace Exploration Agency
This unmanned ship was designed for transporting cargo to the International Space Station. The first of these expendable vehicles will launch this year aboard a new Japanese H-IIB rocket; no manned versions are planned.
2010 | DRAGON
Space Exploration Technologies (USA)
Dot-com millionaire Elon Musk founded Space Exploration Technologies, or SpaceX, to deliver affordable access to space, and he's been developing the Dragon and its Falcon family of rockets with the help of seed money from NASA. In December 2008, NASA went a step further and awarded SpaceX a $1.6 billion contract to service the International Space Station with 12 cargo flights starting in 2010. SpaceX is also working on a crew version of Dragon.
2010 | CYGNUS
Orbital Sciences Corporation (USA)
Orbital Sciences Corporation has also been receiving federal funding to develop alternate rides to orbit, and it too got a NASA contract in December to send cargo to the International Space Station. Orbital's contract is worth $1.9 billion for eight launches aboard the Cygnus capsule, boosted by the company's Taurus II launcher, now in development. Current plans call for cargo flights only, but the company says manned flights wouldn't be out of the question if NASA requested them.
2014 | SUNDANCER
Bigelow Aerospace (USA)
Lockheed Martin and Bigelow Aerospace are studying the conversion of existing hardware to launch crew and cargo to the firm's planned Sundancer space station. While not part of NASA's plans, the Atlas V 401 launcher and the proposed cargo and crew capsules could easily service the International Space Station.
2015 | ORBITAL VEHICLE
Indian Space Research Organization
The prosaically named (for now) Orbital Vehicle has been on Indian drawing boards since at least 2006, and the Indian space agency conducted unmanned re-entry tests in 2007 to gather hard data for a manned re-entry capsule. Actual construction is awaiting government approval for funding, making this the most speculative project of the bunch. The spacecraft would launch on India's Geosynchronous Satellite Launch Vehicle Mark III, now in development.
2020 | AUTOMATED TRANSFER VEHICLE
European Space Agency
An unmanned cargo version of Europe's answer to the Russian Progress cargo ship, with three times the payload, arrived at the International Space Station for the first time last year, boosted by Europe's Ariane 5 launch vehicle. The European Space Agency is studying a four-person manned version dubbed the Crew Transport Vehicle, or CTV, for use in 2020.
7 International Spacecraft that Could Replace NASA's Shuttle - Popular Mechanics