Following on from their successful drop test of the Orion Parachute Test Vehicle (PTV) in February, another test will be conducted on April 17 at the US Army’s Yuma Proving Grounds in Arizona. For this new test, involving a vehicle called PCDTV3, the drogue chutes will be subjected to the the highest dynamic pressure environment to date.
Orion Parachute Tests:
(UPDATE: TEST WAS SUCCESSFUL).
Successful testing of Orion’s parachutes is a vital element of development for NASA’s Beyond Earth Orbit (BEO) spacecraft otherwise known as the Multi-Purpose Crew Vehicle (MPCV).
A serious failure of the parachute system on Orion would result in the final leg of a mission ending in disaster, given it is tasked with providing the correct return orientation for the spacecraft after it has won the battle with the re-entry environment, and is then tasked with slowing the vehicle down to an acceptable velocity for a safe splashdown in the ocean.
Early tests of the parachute system have suffered from a couple of failures, although the old rocket science adage of “this is why we test” is very applicable to everything related to this new spacecraft, with engineers providing numerous improvements to the hardware via the lessons learned.
This resulted in the the successful “second generation” test of Orion’s parachutes in February, a system sporting refinements to the Capsule Parachute Assembly System (CPAS) – mated to a boilerplate Orion – and Parachute Test Vehicle (PTV), riding on a pallet – or sledge – system out of the back of a US Air Force C-17 aircraft.
Dropped from an altitude of 25,000 feet above the Arizona desert, the deployment of the system was picture perfect, allowing for the Orion to release from its pallet system to drop feely under similar conditions it would expect to encounter after re-entry.
The test was the first to create a wake mimicking the full-size Orion vehicle and complete system.
“The test examined how Orion’s wake, the disturbance of the air flow behind the vehicle, would affect the performance of the parachute system,” according to notes on the Orion update section (L2).
“Parachutes perform optimally in smooth air that allows proper lift. A wake of choppy air can reduce parachute inflation. The test was the first to create a wake mimicking the full-size Orion vehicle and complete system.”
It could be argued that the test system is harder to achieve success with than the real thing, due to the numerous additional parachutes that are used to place the PTV into the correct orientation and conditions to that Orion would expect when returning to Earth from a real mission.
Although the boilerplate Orion mock up vehicle and PTV system consisted of eight parachutes in total, another 10 parachutes are required to drag the test vehicle out of the C-17 aircraft, whilst also allowing for the pallet to land safely on the ground under its own dedicated parachutes.
During the 2008 failure, a programmer chute failed to inflate after deployment, the correct test conditions were not met – critically including the requirement for the vehicle’s descent rate to be slowed down and to be correctly orientated for drogue chute deployment resulting in the vehicle falling upside down at high speed.
With the increased velocity, when the two drogue chutes deployed, they were ripped off almost immediately due to the higher loads. The three main parachutes then deployed – again subjected to the higher loads – ripping two of them away from the vehicle, resulting in the inevitable crash landing on the ground.
Another failure in 2010 was believed to be the fault of the pallet system itself, the system that allows the test vehicle to slide out of the back of the C-17. The pallet apparently remained attached to the test vehicle, causing the duo to crash into the ground, again destroying most of the hardware.
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For the recent test, everything went to plan, with the drogue chutes successfully deployed between 15,000 and 20,000 feet, followed by the pilot parachutes, which deployed the main landing parachutes. Orion landed on the desert floor at a speed of almost 17 mph, well below the maximum designed touchdown speed of the spacecraft.
This next test on April 17 will push the boundaries once again, especially for the drogue chutes, as noted by the NASA Orion team.
“The CPAS team continued preparation activities for the Parachute Compartment Drop Test Vehicle (PCDTV3) airdrop test, scheduled for April 17, which will deploy the two drogue parachutes in the highest dynamic pressure environment to date, and will demonstrate a main parachute skipped second stage.”
This test vehicle will also include some improvements to several elements of the parachute system.
“Recent accomplishments include installing the main parachutes into the parachute compartment, including the use of updated design main parachute retention panels; programmer parachute installation; parachute compartment cutter bodies installation; and Mid-Air Release System (MDS) cutter bodies installation.”
Unlike the February test, a boiler plate Orion won’t be used. Instead, the Parachute Compartment (PC) will be mated with a strange looking piece of hardware called the Drop Test Vehicle (DTV) – which looks like an orange missile. The DTV will provide the correct mass and descent velocity conditions for the test. Combined, they make up the PCDTV.
The first “real mission” test of the parachute system will come in 2014, when the Exploration Flight Test -1 (EFT-1) Orion is lofted into a high apogee orbit by a Delta IV Heavy, prior to a re-entry that will mimic Orion returning from a BEO mission, ahead of the use of the parachute system to allow the uncrewed MPCV to splash down in the Pacific.
(Images: Via NASA, L2 and L2 Historical). L2’s new Orion and Future Spacecraft specific L2 section includes, presentations, videos, graphics and internal updates on Orion and other future spacecraft.
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