NASA's "flying saucer" completes second test
NASA has put a new supersonic parachute design through its paces in the second test of its flying saucer-like Low Density Supersonic Decelerator (LDSD). The technology is being developed for future exploration of Mars, where it would allow NASA and its partners to land heavier payloads on the surface.
The idea behind the LDSD is to dramatically increase the amount of drag created by the vessel as it approaches the surface. Its saucer-like form is equipped with a 6-meter Supersonic Inflatable Aerodynamic Decelerator (SIAD), which increases the surface area of the vehicle when inflated. This is designed to reduce velocity enough to deploy the supersonic parachute that is packed into the rear of the craft.
In order to simulate the effects of the Martian atmosphere, the capsule has to be subjected to supersonic speeds at dizzying heights. This is as close as we can get to the conditions above the Red Planet, where the atmosphere is only 1 percent as thick as the Earth's.
Last year's maiden LDSD test proved to be a frustrating affair – in the SIAD inflated perfectly only to see the supersonic parachute torn to shreds before it had a chance to fully deploy.
For new the test, the LDSD was equipped with the same model of SIAD as before, but had a modified parachute with the center constructed from concentric rings. It was hoped that the new design would deliver a marked improvement in strength over the solid center used in the original Supersonic Parachute.
Monday's test had previously been postponed multiple times due to poor weather conditions. The team needed to wait for calm weather to deploy the giant atmospheric balloon that would bring the craft up to a suitable height to initiate the test, and to be certain that the conditions at sea would allow for a swift recovery once the ordeal had come to a close.
The most recent proving flight, which kicked-off at the US Navy's Pacific Missile Range Facility in Kauai, Hawaii, saw the 7,000 lb (3,175 kg) LDSD strapped to the colossal balloon, and carried an impressive 120,000 ft (36,576 m) into the air – three times the height that a commercial Boeing 747 operates.
At this point, the LDSD was dropped, and began a controlled spin to aid stability. Shortly after, the test vehicle's Star 48 solid-fuel rocket engine ignited, and burned for around 70 seconds, accelerating the saucer to Mach four, and pushing it just above the 180,000 ft (54,864 m) mark.
During the flight, four GoPros streamed live, albeit low quality footage of the test. Through the stream, viewers could see the SIAD deploy flawlessly soon after the thruster's fuel was spent, producing a ridged, stable decelerator that succeeded in slowing the test vehicle to around Mach 3.
This brought the team to the moment of truth – the deployment of the Supersonic Parachute. Unfortunately, almost immediately after the 100 ft (30 m) parachute had fully deployed, it appeared to rupture, failing under the immense pressure exerted upon it.
Looking forward, LDSD scientists will examine test capsule once it's salvaged from the Pacific Ocean off the coast of Hawaii where it splashed down, as well as the high definition footage contained in its black box in an attempt to improve the design of the parachute ahead of next year's test, where another SIAD design will be tried. The new iteration is larger in design, and features integrated air intakes that will be used to inflate the decelerator.