From: NASA Exploration Systems Mission Directorate
Posted: Tuesday, August 19, 2008
NASA tested the parachutes for the recovery system on its Orion crew exploration vehicle above the U.S. Army's Yuma Proving Grounds in Arizona on July 31. The test proved unsuccessful when a test set-up parachute failed.
The failed parachute -- called a programmer chute -- deployed, but it did not inflate properly and failed to get the test article that simulated the Orion crew module into the correct orientation, altitude and speed for the test, causing the parachute system for the test vehicle to fail.
"This is the most complicated parachute test NASA has run since the '60's," said Carol Evans, test manager for the parachute system at NASA's Johnson Space Center in Houston. "We are taking a close look at what caused the set-up chutes to malfunction. A failure of set-up parachutes is actually one of the most common occurrences in this sort of test."
To test the first generation design of the recovery parachute system, a mock-up of the Orion crew module was dropped from a C-17 airplane at 25,000 feet altitude.
In addition to the parachute system for the mock-up, the test requires 10 parachutes for preparation of the test. Some of these parachutes extract the mock-up from the airplane. Then pyrotechnics fire to separate the mock-up from the pallet on which it sits while inside the plane. As the mock-up is released from the pallet, a programmer chute and two stabilization chutes are released to set up the proper test condition. At a predetermined time, those chutes are released to start the test of the Orion parachute system. The remaining test preparation parachutes return the pallet to the ground.
The Orion recovery parachute system is based on the parachute system used for the Apollo capsule and uses eight parachutes. There are three types of parachutes in the parachute assembly system: drogues that are designed to stabilize the spacecraft; pilots which pull out the main parachutes; and mains, which are the large parachutes that actually lower the spacecraft to the ground.
The two drogue chutes are deployed to slow the mock-up and ensure it is pointing in the right direction. The drogue chutes are then cut away, and three pilot chutes are deployed and in turn each pull out one of the three main 116-feet-diameter parachutes that will slow the mock-up to a safe landing speed following a launch abort. The pallet has its own parachute recovery system.
During the July 31 test, the programmer parachute and the two stabilization chutes released properly. The programmer parachute did not inflate properly, and the stabilization parachutes inflated but did not stay inflated. As a result, the mock-up dropped faster than intended.
When the test set-up chutes were released, the drogue chutes were immediately cut away, sending the mock-up into a free fall.
During the free fall, the mock-up began to tumble, creating forces that pulled the main parachutes out. Two of the three main parachutes broke free. The third parachute held, but it was torn, too damaged to slow the falling mock-up. The result was a landing that severely damaged the test mock-up.
In addition to testing the parachute system, one of the objectives of this test was to demonstrate the testing techniques. NASA engineers and managers are reviewing the test procedures and the test hardware and set-up, along with the video and photographs collected from the test, to determine what caused the programmer chute to fail.
// end //