LDSD Archives

Feeling dizzy? This is what the view looked like from NASA’s next-generation Mars spacecraft as the flying saucer-shaped vehicle did a test in June.

According to the agency, the Low-Density Supersonic Decelerator (LDSD) met all of its test objectives even though the parachute didn’t deploy as planned. And in a briefing today (Aug. 8), agency officials said they have a plan to deal with the issue for the next flight, which will be in summer 2015.

“We are going to change the shape. We are going to have some structural reinforcements to make it stronger in areas that it is particularly sensitive, to
improve deployment of parachute,” said Ian Clark, the principal investigator of LDSD at NASA’s Jet Propulsion Laboratory.

With every robotic Mars mission, it appears, NASA is trying to land bigger and bigger payloads on the surface of the planet. That’s because the rovers have become more powerful over time. The latest vehicle, the Mars Science Laboratory (better known as Curiosity) included a unique crane system that was so innovative that NASA dubbed the final landing sequence “seven minutes of terror.”

The LDSD test in late June saw the craft soar to 120,000 feet (36,576 meters). The vehicle was then cut from the balloon at this altitude, which has densities similar to what you would expect in the upper Mars atmosphere, to see how it would do during a simulated descent to the Red Planet.

“We’re really happy. We have tons and tons of data,” said Mark Adler, the project manager for LDSD at JPL. “Nothing makes us happier than data.”

Besides the busted parachute, officials said the test showed the vehicle was performing to expectations — and sometimes, even better than expected. The shape held within 1/8 of an inch (0.32 cm), which they said was very good for a 20-foot (6-meter) vehicle. Drag and stability happened as they thought. The balloon that deployed the parachute also did well, they said.

A timeline of events for a test of NASA's Low-Density Supersonic Decelerator (LDSD). Credit: NASA/JPL-Caltech — A timeline of events for a test of NASA’s Low-Density Supersonic Decelerator (LDSD). Credit: NASA/JPL-Caltech

The parachute, however, developed tears very close to the beginning of its deployment, which officials said was due to a lack of understanding about how parachutes perform at supersonic velocities.

While the LDSD has not been assigned to a particular mission yet, officials said it would be useful to land missions more accurately on the Red Planet in spots that would be more difficult to reach. It also would be useful for a future human mission, whenever that happens, because the equivalent of “two-storey condominiums”would be needed, said Adler.

The project has been in the works since September 2010, and this summer’s test occurred a year ahead of schedule.

“You wanna go to Mars, you wanna go big? Then you gotta test big here,” says mechanical engineer Michael Meacham, and testing big is exactly what he and other engineers at NASA’s Jet Propulsion Laboratory have done to develop a new supersonic parachute for future Mars landings.

The process of putting things onto Mars has traditionally used the same couple of tried-and-true methods: inflatable, shock-absorbing bouncers and large parachutes combined with retro-rockets (most recently seen in the famous “Seven Minutes of Terror” Curiosity landing in August 2012.) But both methods are limited in how large and massive of an object can safely be placed on the Martian surface. For even larger-scale future missions, new technology will have to be developed to make successful landings possible.

Enter the LDSD, or Low-Density Supersonic Decelerator, an enormous parachute — similar to the one used by Curiosity except bigger — that can slow the descent of even more massive payloads through the thin Martian atmosphere.

Of course, part of the development process is testing. And in order to run such a large chute through the same sorts of rigors it would experience during an actual Mars landing, JPL engineers had to step outside of the wind tunnel and devise another method.

The one they came up with involves a rocket sled, a Night Hawk helicopter, a 100-lb steel bullet, a kilometer-long cable (and lots and lots of math.) It’s an experiment worthy of “Mythbusters”… watch the video above to see how it turned out.

“When we land spacecraft on Mars, we’re going extremely fast… we have got to slow down. So we use a parachute. And we use a really BIG parachute.”
– Michael Meacham, Mechanical Engineer at JPL

Tag: LDSD

Watch This Prototype Mars Spacecraft Spin During A Supersonic Test

JPL Tests Big with a Supersonic Parachute for Mars