A gigantic supersonic parachute that NASA is developing to help land heavy payloads on Mars was torn apart during Monday's "flying saucer" test flight over Hawaii, agency officials said.
The 100-foot-wide (30 meters) parachute — the biggest such chute ever deployed — unfurled well and apparently inflated fully, or nearly fully, on Monday before being ruptured by the fast-rushing air during the second flight test of NASA's Low-Density Supersonic Decelerator project, also known as LDSD.
"The damage propagated further until the parachute could no longer survive the harsh supersonic environment," LDSD principal investigator Ian Clark of NASA's Jet Propulsion Laboratory said during a news conference on Tuesday. [Test Flight Photos for NASA's 'Flying Saucer']
"On this project, we're pushing the limits of our technologies, our engineering and our understanding of aerodynamic decelerators," Clark added. "This year, the physics of supersonic parachutes pushed back on us."
The LDSD program is developing technology to help get human habitat modules and other heavy gear down softly on the surface of Mars.
The big supersonic chute — which is twice as wide as the parachute that slowed the descent of NASA's Curiosity rover through the Martian atmosphere in August 2012 — is one of two core components of LDSD tech. The other is a "supersonic inflatable aerodynamic decelerator," or SIAD, a saucer-like cushion designed to fit around the rim of an atmospheric entry vehicle.
The SIAD can be inflated to 20 feet (6 meters) in diameter, increasing its surface area and atmospheric drag.
Reviewing the data
During Monday's test, a high-altitude balloon brought the LDSD craft up to 120,000 feet, and then a solid-fueled rocket motor pushed it up even higher, to 180,000 feet. Conditions so high up in Earth's atmosphere mimic those that a spacecraft would encounter at Mars.
The SIAD deployed as planned at Mach 3. The supersonic parachute also performed well at first, but then the tear developed.
The team won't know the full details of what happened until they analyze the high-resolution data stored onboard the LDSD vehicle's "black box," Clark said. Recovery boats retrieved the craft from the Pacific Ocean and are ferrying it back to shore. [Infographic: How to Land on Mars: Martian Tech Explained]
Monday's trial marked the second flight test for LDSD technology. The first, which occurred in June 2014 from the Pacific Missile Range Facility, proceeded similarly: The SIAD worked well, but the parachute was torn apart shortly after deployment.
Signs of improvement
Although the redesigned chute also failed, team members saw signs of improvement.
Last year, "we saw the parachute be damaged very, very early in the inflation process," Clark said. "This year, with the low-resolution data that we have presently, it looks like the parachute remained largely intact, if not entirely intact, up to the point of full inflation. And we also saw more drag being generated out of this parachute this year than we did last year. So those are both pluses."
LDSD project manager Mark Adler said he considered both test flights to be successful.
"We very much want to have these failures occur here in our testing on Earth, rather than at Mars," Adler said. "So it's a success in that we are able to understand and learn more about the parachute so that we can get confidence, and have highly reliable parachutes for when we have a large mission going to Mars."
Clark and colleagues will keep working on the parachute, aiming to test another version from Hawaii next year. NASA set aside $230 million for the LDSD project, which calls for three flight tests. But certifying the supersonic chute will require two successful test flights, so more money will probably have to be budgeted for a fourth balloon-aided mission down the road, Adler said.