In Thursday's test, a model of the X-38 was carried aloft by a B-52 bomber, the same carrier airplane that once hauled the X-15 research rocketship in the 1950's and 1960's. At 8:30am PST, the wingless craft, based on a U.S. Air Force spacecraft design more than 25 years old, was released for descent to the desert floor. Within four seconds after separation, the X-38 deployed a special kind of steerable parachute called a parafoil, or parasail.

The chute alllows ground controllers to direct the craft to different landing sites. The sail was successfully deployed, but during the glide back down to earth a tear developed in the chute that is now under investigation. The damage did not effect the landing of the craft, but space officials want to better understand what caused the tear before sending the X-38 prototype up again.

Following a series of tests during the next two years, a larger full scale version of the vehicle will be launched in the payload bay of a Space Shuttle and placed adrift in orbit. The unmanned craft will then be brought back to a controlled landing in a full test of its ultimate mission. NASA and the space station's international partners will keep X-38 vehicles docked at the station for immediate emergency escape should troubles arise.

Astronauts will be able to board the craft and ride it back to earth without need for controls - that function will be performed by "pilots" on the ground. The X-38 will become operational on the station by 2003, if the series of tests that started Thursday prove the design.