Landing on Mars is hard, and the heavier your payload the harder it gets. But NASA’s working on the problem, and the next generation landing system will involve the Low-Density Supersonic Decelerator, aka the “Flying Saucer”.
Landing on Mars is tricky. The planet’s atmosphere is about one percent as thick as what we have on Earth. It’s extremely thin, but not thin enough that we can ignore it when going in for a landing. It’s also not thick enough to slow a spacecraft by atmospheric drag alone. Everything NASA has landed on Mars used a parachute and retrorockets, with some missions using airbags or the Sky Crane airbags for the final landing.
But all those systems are about at their limit; the Curiosity rover is pushing the envelope for the heaviest payload we can actually land on Mars. Enter the LDSD, a 15-foot-wide, 7,000-pound vehicle.
The LDSD is testing a new means to land heavier payloads on Mars by taking advantage of atmospheric drag. It works by increasing its surface area in flight. Expansive, kevlar balloon-like structures called the Supersonic Inflatable Aerodynamic Decelerators (SIAD) packed along the perimeter of the disk-shaped vehicle inflates, increasing the disk’s surface area almost 50 percent without making it heavier. This increases the drag, slowing its descent towards the surface.
Of course, we have yet to see this land a payload on Mars. For the time being, the LDSD is undergoing high altitude, supersonic testing off the coast of Hawaii. The vehicle is raised by a balloon then starts spinning to stabilize its flight. Once spinning, its solid rocket motor ignites to propel it to a top speed of Mach 4. Then the spin is stopped and the SIAD inflates, slowing it to about Mach 2.5. Finally, a ballute deploys to pull out the main, massive parachute.
Last summer, the LDSD performed perfectly but the parachute failed. The team is hopeful they’ve fixed this problem.
Today’s spin test was to make sure that the vehicle is balanced and will spins evenly. The test in the clean room at NASA’s Jet Propulsion Laboratory only saw the LDSD spin 30 times per minute. In flight it will spin at 50.
The next LDSD test will take place next summer from the Pacific Missile Range Facility on Kauai, Hawaii. And then, hopefully, we’ll see it landing bigger and better payloads on Mars.
IMAGES: Amy Shira Teitel