Internal Memo Details Failed NASA Orion Parachute Test Vehicle Drop Test

image

According to an internal NASA memo CPAS Cluster Development Test 2 (CDT2) experienced a test failure on 31 July 2008.  Initial observations indicated that the programmer parachute did not inflate properly when the Parachute Test Vehicle (PTV) separated from the test pallet.

The programmer parachute puts the PTV into the proper position and thus sets up proper initial conditions for descent to the ground. In this test, the programmer parachute failed to inflate. This was due to the fact that the programmer parachute did not take in enough air to fully inflate and produce the proper drag. This situation occurred because of hard buffeting produced by the wake formed by the PTV and the stabilization parachutes. 

When the programmer and stabilization parachutes were jettisoned and drogue parachutes were deployed, the PTV was pitched over nearly 90 degrees.  As such, the PTV was inverted (i.e. its apex pointing forward) by the time the drogue parachutes reached line stretch. 

The combination of high dynamic pressure and inverted deploy (drogue parachute risers were wrapped around the PTV) caused the drogue parachutes to immediately cut away. 

The PTV generated such a high flip rate that the g-forces pulled out the main riser and harness out of their stowage bags.  This in turn led to the failure of the main bag retention system. 

The main d-bags separated from the PTV.  As the yrose above the vehicle, they pulled the pilot parachutes out of the mortar tubes and extracted the main parachutes.  Two of the three main parachutes separated immediately and the PTV came down on only one main parachute.  The PTV hit the ground immediately after the second of three reefings. 

According to the memo "This is initially classified as a test technique failure and not a failure of the CPAS system."

NASA Orion Parachute Test Vehicle Fails Drop Test, earlier story


Please follow SpaceRef on Twitter and Like us on Facebook.