NASA has upped the ante in its most recent test of the Orion spacecraft's parachute deployment system ahead of its maiden test flight scheduled for launch later this year. Today's operation saw a test version of the Orion crew module falling through the skies above Arizona on the 14th of 17 planned drops designed to test a soft landing system which may one day protect astronauts returning from missions to Mars.
During today's proving mission, the mock Orion spacecraft was dropped from a Boeing C-17 Globemaster flying 35,000 ft (10,668 m) above the Arizona desert. Initially, the capsule fell in a controlled manner under programmer parachutes designed to allow the crew module to fall at a controlled pace. However, to further stress test the system, after detaching from the programmer parachutes, mission operators allowed ten seconds of freefall to pass before deploying Orion's first set of parachutes, increasing the spacecraft's speed and intensifying the strain on the descent system.
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Such stress tests are vital, as upon returning from a deep space mission from destinations such as Mars, NASA scientists predict that upon making contact with the Earth's atmosphere, Orion would be traveling at speeds in excess of 20,000 mph (32,187 km/h). While re-entry through the atmosphere will have the effect of slowing the crew module to speeds of around 350 mph (563 km/h), the 20,000 lb (9,072 kg) spacecraft would still need to slow to a mere 20 mph (32 km/h) to accomplish a safe splashdown in the Pacific Ocean.
Arguably the most important stage of the test took the form of the initial parachute deployment, designed to remove Orion's forward bay cover which, when in use, forms a protective shell over the top of the crew module. This particular element of the descent process had only ever been tested once before, with today's test representing the final time it will be used prior to EFT-1.
While in flight, the covering protects Orion's parachutes from the harsh environments of deep space and re-entry. However, if the covering is not successfully detached from the crew module upon descent, the parachutes would be blocked and unable to deploy, leaving Orion and it's crew helpless in a fatal freefall. Therefore as a fail-safe, just in case the force of the parachutes is not enough to dislodge it, small thrusters mounted on the forward bay cover are designed to fire in conjunction with the deployment of the parachutes assuring that the two drogue, and three main parachutes can deploy unimpeded.
No chances are being taken with the safety of future crewed missions, so to simulate a partial failure in the parachute deployment system, NASA engineers skipped what is known as a reefing stage for one of Orion's three main parachutes. The reefing stage is essentially a process that allows each of Orion's three 115 ft (36 m) main parachutes to open in a gradual and controlled manner.
During the test, disabling this feature had the effect of opening one of the main parachutes in a sudden, premature fashion. However, the parachute apparently suffered no obvious damage, and in no time Orion was descending to the surface of the Arizona desert under three fully deployed main stage parachutes.
Three more drops are scheduled to further test the descent systems, with the next drop in August focusing on how Orion would react upon descent to a simulated failure in one of it's three main parachutes.