EDWARDS AIR FORCE BASE, Calif. - A prototype of NASA's ''flying lifeboat'' that will eventually ferry astronauts from the International Space Station to Earth made its highest and longest free flight on Thursday.
The unmanned X-38 was launched from under the right wing of a B-52 at 39,000 feet and fell for more than 40 seconds until a parachute deployed. About 10 minutes later, the wedge-shape vehicle landed safely in a cloud of dust on a dry lake bed.
''The vehicle flew just about as we expected,'' said Bob Baron, the X-38 project manager at NASA's Dryden Flight Research Center. ''We purposely put in some pitches and rolls. All that looked very, very good.''
The wingless and engineless prototype is validating technology that will be used to build a Crew Return Vehicle for the space station currently under construction. The $85 million testing project's findings will be used to build the actual CRV.
The goal is to build the first manned space vehicle since the space shuttle at a fraction of the cost.
''It just seems to me we've done very well, very quickly and rather inexpensively,'' Baron said.
For the first years of the space station, astronauts will have to rely on a three-man Soyuz capsule for emergency escapes. Eventually, Crew Return Vehicles that can carry up to seven people will be available.
Thursday's test focused on evaluating the performance of the vehicle's flight control system, air data systems and drogue parachute performance. Data collected from onboard computers will be shipped to Houston for analysis, Baron said.
After free-falling for nearly a minute, a drogue parachute popped from the X-38, causing it to spin slightly as the craft stabilized. About a minute later, a 5,500-square-foot parachute - as wide as the wings of a Boeing 747 - deployed.
The vehicle used Thursday is only about 80 percent of the full size of the final CRV. Another model that more closely resembles the vehicle will undergo testing later this year and use the actual CRV parafoil, which covers 7,500 square feet.
Unlike airplanes and space shuttles, the X-38 has skids rather than landing gear. A left skid failed to deploy during Thursday's test, but it did not cause any problems during the landing, Baron said.
''We need to find out exactly why it didn't deploy,'' he said. ''But even with one of the gears not down, the vehicle didn't roll over or flip over. It gives you some feeling that the system is robust.''
Thursday's test was the fifth free flight of the program since its inception in 1995. Officials hope to test a full-scale model launched from a space shuttle in April 2002 and make it available on the space station in 2005 or 2006.