GRAHAM WARWICK / WASHINGTON DC
Launch pad demonstration will be a key milestone in the development of the ISS crew rescue vehicle
NASA and Lockheed Martin are preparing to review the requirements for a launch pad abort demonstration that will be a key milestone in development of the planned Orbital Space Plane (OSP). The abort demonstration is intended to show that the OSP crew can safely escape the launch pad explosion of a Boeing Delta IV or Lockheed Martin Atlas V evolved expendable launch vehicle (EELV).
Lockheed Martin is under contract to perform up to seven test flights of a rocket-powered crew escape module with a parafoil recovery system. As the OSP design has yet to be selected, the company plans to build a core structure that can be adapted to the outer mould line of the final vehicle. The module will be powered by four 50,000lb-thrust (222kN) liquid rocket engines to provide the acceleration required to escape the fireball and get far enough downrange of the explosion to be safe. The parafoil from the X-38 crew rescue vehicle demonstrator will be used for recovery.
"The first two flights will demonstrate acceleration and recovery," says Lockheed Martin pad abort programme manager Carol Giffen. Later flights could look at different outer mould lines, propulsion systems and crew seats, she says. The first launch is planned for mid-April 2005 at the White Sands, New Mexico, missile range, with tests following every three months until October 2006. Unmanned launches of the OSP as a crew rescue vehicle for the International Space Station are scheduled to begin in 2010, followed in 2012 with manned launches as a crew transfer vehicle.
A crew escape module will be the principal means by which the EELVs will be man-rated. The demonstration is focused on an abort on the launch pad, but could be extended later to look at crew escape during ascent and re-entry, says Giffen. NASA is updating its explosive environment data to reflect the recent decision to launch the OSP on a heavylift version of the Atlas V or Delta IV. This includes "how big the blast wave is, how fast it is travelling, and how fast we have to get away and how far downrange", says Giffen.
The demonstrator will carry two instrumented crash-test dummies to measure launch and impact loads imposed on the crew during a pad abort. "We are looking at several different types of mannequin," says Giffen. NASA is still looking at the balance of impact attenuation between the seats and the structure, she says. The liquid-oxygen/ethanol engines to be used were developed by Boeing Rocketdyne for NASA's Bantam small launcher programme.
Source: Flight International
