A launch pad abort test vehicle, being designed in support of NASA's Orbital Space Plane (OSP) program, proved stable in wind tunnel tests completed this month. The successful tests set the stage for engine test firings and parachute drop tests later this year.
The Pad Abort Demonstration (PAD) Project is designed to demonstrate a crew rescue capability important to future space transportation systems. The PAD will be a full-scale, reusable system incorporating crew escape and survival systems, subsystems and components using proven technologies to help NASA achieve its goals of establishing safe, reliable and affordable access to space.
The PAD vehicle, being designed by Lockheed Martin, demonstrated the stability and maneuverability under simulated conditions approximating escape from a catastrophic launch vehicle failure. The tests were conducted in September and October at Lockheed Martin's High Speed Wind Tunnel in Grand Prairie, Texas.
Maintaining stability, without a complex attitude control system, will ensure a safe transition to recovery under a parachute cluster. The PAD flight profile consists of a powered phase lasting five seconds, reaching six to eight times the force of normal gravity and simulating separation from the launch system after a pad mishap. The powered phase is followed by an unpowered glide from Mach 0.9 (660 mph) down to Mach 0.3 (220 mph), when the parachute system deploys.
"These wind tunnel tests are an important success on the way to developing a safe and effective crew escape system," said Chuck Shaw, PAD Project Manager at NASA's Johnson Space Center (JSC), Houston. "The tests follow September's completion of the PAD Preliminary Design Review, pave the way for initial testing of the vehicle's engine in November and a first set of parachute drop tests in December," he said.
NASA awarded a contract to Lockheed Martin in November 2002 to design and build a crew escape and survivability system demonstrator and to establish a flexible test bed for use in support of the OSP. The PAD Project is a pathfinder for integrating a crew escape capability into spacecraft design, something that has not been done since the Apollo program.
For the initial flight test in mid-2005, the PAD will consist of a representative crew escape module mounted on the pusher propulsion module. A flared structure attached to the propulsion module provides the necessary aerodynamic stability. Flight tests will use instrumented mannequins to measure the environments a human crew would experience.
The PAD project is managed at JSC. The OSP Program is managed from NASA's Marshall Space Flight Center in Huntsville, Ala.
The OSP program will support U.S. International Space Station requirements for crew rescue, crew transport, and contingency cargo. The vehicle will initially launch on an expendable launch vehicle, to provide rescue capability for no fewer than four Station crewmembers, as early as 2008. Crew transfer to and from the Space Station is planned as soon as practical but no later than 2012.
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