A NASA "flying saucer" air brake system designed to help land larger and heavier payloads on the surface of Mars has undergone a test flight high above Earth, the space agency says.
The rocket-powered, disc-shaped vehicle flew to the edge of space, reaching 190,000 feet following a trip into the upper atmosphere courtesy of a giant helium balloon launched from Hawaii, NASA said in a release this week.
Air density and pressure at such altitudes is the nearest thing to conditions above Mars available to engineers testing the saucer-shaped Low-Density Supersonic Decelerator, it said.
The rocket attached to the LDSD accelerated it to Mach 4, four times the speed of sound, approximately the same speed a spacecraft would be going as it entered the Mars' thin atmosphere.
During the test, which took place in June, two additional technologies were tested: a Supersonic Inflatable Aerodynamic Decelerator, a doughnut-shaped structure that slowed the craft from Mach 3.8 down to Mach 2, and a Supersonic Disksail Parachute, the largest parachute ever tested at supersonic speeds.
The parachute has around twice the surface area of that of the Mars Science Laboratory mission's parachute, used to place the rover Curiosity on the Red Planet's surface.
"A good test is one where there are no surprises but a great test is one where you are able to learn new things, and that is certainly what we have in this case." said Ian Clark, principal project investigator NASA's Jet Propulsion Laboratory in Pasadena, California. "Our test vehicle performed as advertised."
In the test high above Earth, the LDSD structure inflated rapidly to its final diameter of 20-feet, holding its shape to within less than an inch, "pretty remarkable" for an inflated structure, Clark said.
The purpose of the doughnut-shaped air brake is to increase the vehicle's surface area to dissipate energy through frictional heating as it descends through the atmosphere.
Less successful was the trial deployment of the supersonic parachute, which came apart and shredded as the LDSD plunged to Earth at 2,500 mph.
"We've leaned that we have more to learn about supersonic parachute inflation," Clark said. "There's a lot of physics to this problem that we're now getting new insights into."
In additional to allowing for larger payloads to Mars, the LDSD will allow landings on the Red Planet at higher altitudes where the atmosphere is thinner, JPL said.
Engineers said there would be two more tests conducted next year from the Pacific Missile Range Facility in Hawaii, operated by the U.S. Navy.
