NASA Conducts Successful Pad Abort Demonstration
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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