The flying saucers of science fiction movies might be the shape of things to come for future Mars missions that are expected to involve larger payloads that today's landing vehicles are not equipped to handle.
The saucer-shaped landing systems in development, part of NASA's Low-Density Supersonic Decelerator project, will be sent into near-space in June from the U.S. Navy's Pacific Missile Range Facility in Hawaii.
Scientists provided a mission overview in a "clean room" Wednesday at NASA's Jet Propulsion Laboratory in Southern California. Reporters were required to wear lab suits and hats.
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"If you want to land bigger and bigger payloads, you need ways of growing the size of the vehicle to create more drag," said JPL's principal investigator Ian Clark, likening the vehicle to a puffer fish.
Current landing technologies rely primarily on parachute designs dating to the 1970s Viking Program. That design placed two landers on Mars in 1976 and the same basic technology was used about 35 years later when the Curiosity rover landed on Mars' surface.
After a parachute deployed high above Mars' surface, rocket thrusters were used to slow Curiosity's landing vehicle. The rover was then dropped by cables from the spacecraft and gently placed on the landing site before the tethers were disconnected and the spacecraft soared clear of the site.
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NASA's landing vehicles in development would use the saucer shape to maximize atmospheric drag -- slowing and stabilizing the spacecraft after it enters Mars' atmosphere for final approach, a process described as "six minutes of terror." Increasing drag would save rocket engines and fuel required for complex landing maneuvers.
Friction already slows a spacecraft considerably after it enters Mars' atmosphere during the first four minutes of entry. But the spacecraft is still traveling at about 1,000 mph at that point and decelerates to about 200 mph after parachute deployment, which occurs at about 300 feet from the surface, according to NASA.
Thruster rockets, giant airbag cushions and tethers can all be used for the remainder of the descent, but the larger payloads possible in future Mars missions require something more advanced. The decelerators being developed by NASA -- pufferfish-like inflatable devices and an improved parachute -- can almost double payload mass, according to researchers.
The concept was ground-tested using a rocket sled in June 2012. The balloon-like inflatable devices extend around the vehicle to increase drag. A large parachute would then deploy to scrub off more speed.
The parachute is so large it did not fit in a wind tunnel, so researchers used the rocket-powered sled test at the U.S. Naval Air Weapons Station at China Lake.
The upcoming test flights will give scientists a better idea of how the technology works when the saucer is sent high above Earth. The vehicles could be used in Mars missions as early as 2018, according to NASA.
When asked what was so sensitive about the project that it needed to take place in a clean room, Clark laughed, "It is the only space we had available."