An artist's conception of SpaceX's Dragon craft in orbit.
A new space race is on among commercial companies hoping to snag a lucrative contract to ferry astronauts to the International Space Station.
After NASA's space shuttles retire next year, astronauts will be left without an American-built means of transportation to space. The new NASA authorization bill passed earlier this month authorizes the space agency to hire space vehicles through the private sector for this purpose as soon as they're available.
Four companies that are hoping to fill that role presented their spaceship designs Oct. 21 the 2010 International Symposium for Personal and Commercial Spaceflight in Las Cruces, N.M. The spaceships are also aiming to fly tourists to orbit, and to service commercial space stations such as those under development by Bigelow Aerospace, once they are built. [Top 10 Private Spaceships Becoming Reality]
With several companies aiming for orbit, the options are open for would-be space tourists looking to buy a ticket to space. Here's a look at the four contenders seeking to fill the orbital needs of future space travelers:
Lockheed Martin's Orion capsule
This spacecraft under development by Lockheed Martin was originally designed to carry crews to the space station and the moon under NASA's Constellation program, which has since been canceled. The moon-oriented Constellation program has been replaced with a new space plan aimed at sending astronauts to an asteroid by 2025.
But plans for the Orion capsule were revived under the new NASA vision as an emergency lifeboat that astronauts could ride home if they needed to escape from the International Space Station.
Lockheed is hoping to develop the craft further to carry crews up to space, as well as down.
"We're well along in the development," said Kenneth Reightler, vice president of NASA program integration at Lockheed. The vehicle has already passed its phase 1 safety review, and some systems have even gone through the next step, called critical design review.
Because Orion was originally designed to go to the moon, it has met the stringent standards for deep space exploration, which are more than will be required for transportation to low-Earth orbit and the International Space Station, he said.
"What you're left with is an incredibly capable spacecraft for LEO," Reightler said.
Dragon: SpaceX's gumdrop spaceship
Space Exploration Technologies has designed not only its own gumdrop-shaped space capsule, but a rocket to fly it on. The company's Falcon 9 booster launched successfully on its first flight test in June 2010. The Dragon capsule, designed to carry either crew or cargo to low-Earth orbit, is due to make its debut spaceflight on the Falcon 9 as early as next month.
SpaceX already has a $1.6 billion contract with NASA to haul cargo to the International Space Station aboard Dragon, and it's a leading contender for the coveted duty of carrying crew there as well.
"SpaceX's mission is to provide the safest, most economical and reliable transport to low-Earth orbit," said former NASA astronaut Ken Bowersox, SpaceX's vice president of astronaut safety and mission assurance.
SpaceX estimates that it will take about 2 1/2 years to convert Dragon from its cargo configuration to a spacecraft ready to launch with people aboard. The main hurdle will be designing a launch escape system, Bowersox said.
"A lot of people think that's a very aggressive timeline," he added. "SpaceX likes aggressive timelines."
Tickets aboard a Dragon flight should cost about $20 million, with the total price of a launch coming in around $140 million to $150 million, Bowersox said.
For comparison, the most recent space tourist flight to the International Space Station on Russian Soyuz spacecraft, arranged by the Virginia-based firm Space Adventures, carried a cost of about $35 million.
Boeing's CST-100 space capsule
This entry from Boeing into the commercial space transportation fray is a capsule larger than NASA's Apollo spacecraft but smaller than Orion.
"We've kept it very, very simple," said Keith Reiley, Boeing's program manager for commercial crew development and space exploration.
Called the Crew Space Transportation 100, or CST-100, the capsule could potentially launch aboard a ULA Atlas 5 or Delta 4 rocket, or even one of SpaceX's Falcon 9s. It would likely lift off from New Mexico's White Sands Missile Range, with Edwards Air Force Base in California as a backup site.
The price per seat on the CST-100 space capsule is not yet determined, but it will depend on how often the vehicle can fly.
"It's all about flight rate," Reiley said. "The fact that NASA provides funding to help support development ? that?s a very big deal. The more flights you fly, the cheaper it will get."
Boeing received $18 million from NASA in February 2010 to develop the spacecraft under an existing commercial crew development competition.
Dream Chaser: A new space plane
This space plane design under development by the Sierra Nevada Corporation in Centennial, Colo., is expected to fly atop a United Launch Alliance Atlas 5 rocket, which is an expendable launch vehicle. The spaceship will carry up to seven people to the International Space Station, and could even be adapted to carry cargo or to service satellites in space.
Dream Chaser also won money from NASA in the February 2010 contest ? Sierra Nevada was the top winner, taking home $20 million.
"We call it the Dream Chaser because I like chasing dreams," said Mark Sirangelo, corporate vice president and chairman of Sierra Nevada Space Systems.
The craft stands apart from most other competitor designs in that it is not a capsule like the Soyuz and Apollo spacecraft, or like the Orion, Dragon or CST-100 vehicles.
"We at Sierra Nevada are doing something a little bit different," Sirangelo said.
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