By Irene Klotz
(Reuters) - A privately owned prototype space plane aced its debut test flight in California but was damaged after landing when a wheel did not drop down, developer Sierra Nevada Corp said on Tuesday.
The Dream Chaser is one of three space taxis under development in partnership with NASA to fly astronauts to the International Space Station following the retirement of the space shuttles in 2011.
While competitors Space Exploration Technologies - a privately owned firm also known as SpaceX - and Boeing are working on seven-person capsules that return to Earth via parachutes, Sierra Nevada's Dream Chaser resembles a miniature space shuttle with wings to glide down for a runway landing.
The company took a significant step toward proving Dream Chaser can fly with its first unmanned glide test at Edwards Air Force Base in Mojave, California, on Saturday, Sierra Nevada Vice President Mark Sirangelo told reporters on a conference call.
A full-size Dream Chaser model was carried to an altitude of about 12,500 feet by a heavy-lift helicopter and released for a minute-long glide back to the runway.
"The first thing we needed to do was find out 'Does this shape, does this type of vehicle actually fly? Is it air-worthy?' Although all the computer modeling and the simulations told us it was, there had not been a lifting body of this type flown since the 1970s," Sirangelo said, referring to the test flight of NASA's prototype space shuttle Enterprise.
After being released, the autonomously controlled Dream Chaser successfully positioned itself for flight, flared its nose to slow for touchdown and settled on the runway, Sirangelo said.
However, one of the vehicle's three landing gears did not deploy, causing the plane to skid off the landing strip and end up in the sand, he said.
Engineers are still assessing how much damage was sustained. Sirangelo said the crew cabin and onboard computers were not damaged.
The landing gear used during the test flight is not the same equipment planned for the orbital vehicles, he added.
Ironically, the accident may speed up Sierra Nevada's planned piloted test flight next year. The vehicle had been scheduled for a second autonomous flight in California before being returned to its Colorado manufacturing facility to be outfitted for a piloted flight.
"We were fortunate enough to get almost all the data we needed on the very first flight. If that's the case, we may just move on to the next phase of the program," Sirangelo said.
NASA hopes to buy rides commercially to carry its astronauts to the space station by 2017.
(Reporting by Irene Klotz, editing by Jane Sutton and Cynthia Osterman)