Article Posted on : - May 07, 2010

The PA-1 launch abort system being test launched from the White Sands Missile Range. A NASA photo

WASHINGTON (BNS): NASA has successfully tested its Pad Abort 1 (PA-1), the unmanned launch abort system (LAS) it has designed for the Orion crew vehicle.

The PA-1 lifted off from the White Sands Missile Range at 1300 GMT on Thursday. The flight lasted about 135 seconds from launch until the crew module touchdown about a mile north of the launch pad, NASA said.

This was the first flight test of the fully integrated launch abort system. The LAS has been designed to activate within milliseconds in the event of an emergency on the launch pad or during initial ascent of the spacecraft.

The test involved three motors. An abort motor produced a momentary half-million pounds of thrust to propel the crew module away from the pad. It burned for approximately six seconds, with the highest impulse in the first 2.5 seconds. The crew module reached a speed of approximately 445 mph in the first three seconds, with a maximum velocity of 539 mph, in its upward trajectory to about 1.2 miles high.

The attitude control motor fired simultaneously with the abort motor and steered the vehicle using eight thrusters producing up to 7,000 pounds of thrust. It provided adjustable thrust to keep the crew module on a controlled flight path and reorient the vehicle as the abort system burned out.

The jettison motor, the only motor of the three that would be used in all nominal rocket launches, pulled the entire launch abort system away from the crew module and cleared the way for parachute deployment and landing. After explosive bolts fired and the jettison motor separated the system from the crew module, the recovery parachute system deployed. The parachutes guided the crew module to touchdown at 16.2 mph, about one mile from the launch pad, NASA said.

The information gathered from Thursday's test will help refine design and analysis for future launch abort systems, resulting in safer and more reliable crew escape capability during rocket launch emergencies, the space agency said.