The Low-Density Supersonic Decelerator will take its first big step on the road to Mars tomorrow. The spacecraft will undergo a "spin table test" at the Pacific Missile Range Facility in Hawaii. The event will stream from 2:30 to 3:30 p.m. EST on NASA JPL's live stream.

The 15-foot-diameter craft is shaped like a flying saucer, and inflates to its size through a series of balloons that increase the surface area of the craft. It uses drag to decelerate from Mach 3 to Mach 2, preparing its payload for a softer landing on the Martian surface. This table test is a demonstration of how the craft will spin as it decelerates NASA's cargo during the descent.

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Because Mars has a much thinner atmosphere than Earth, simple solutions like a parachute are typically not enough on their own to slow down a spacecraft to a safe speed. That's why NASA has to use creative solutions like the sky crane that lowered Curiosity to the Martian surface.

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Solutions like a parachute are not enough on their own to slow down a spacecraft to a safe speed

The LDSD is also meant to save on rocket fuel during landings, which would allow NASA to use the rockets for "final maneuvers and landing procedures." In addition, LDSD potentially could haul heavier cargo and land it at higher altitudes, enabling NASA to explore more varied terrain, like mountains and plateaus. The system has been through one successful flight test in June 2014 to determine its flight readiness, though that was not a full-scale launch.

Eventually, NASA will conduct full flight tests with its flying saucer in Earth's atmosphere. If it works, then perhaps one day this will be the system that allows manned missions to safely descend to the martian surface.

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Source: NASA

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John Wenz
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John Wenz is a Popular Mechanics writer and space obsessive based in Philadelphia. He tweets @johnwenz.