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• At nearly 2,000 pounds, Curiosity is too heavy, so engineers had to come up with a new way to land. Friction from the thin atmosphere isn't enough to slow down the spacecraft without some help.
• During its fiery plunge, Curiosity will brake by executing a series of S-curves -- similar to how the space shuttle re-entered Earth's atmosphere. At 900 mph, it will unfurl its huge parachute. It then will shed the heat shield that took the brunt of the atmospheric friction and switch on its ground-sensing radar.
• A mile from the surface, Curiosity will jettison the parachute and fire up its rocket-powered backpack to slow it down until it hovers. Cables will unspool from the backpack and slowly lower the rover -- at less than 2 mph. The cables keep the rocket engines from getting too close and kicking up dust.
• Once the rover senses touchdown, the cords will be cut.
• Even if the intricate choreography goes according to script, a freak dust storm, sudden gust of wind or other problem can mar the landing.
• "The degree of difficulty is above a 10," said Adam Steltzner, an engineer at NASA's Jet Propulsion Laboratory, which manages the mission.
• It takes 14 minutes for radio signals on Mars to travel to Earth. The lag means Curiosity will already be alive or dead by the time mission control finds out.
• The rover's landing target is Gale Crater near the Martian equator. It's an ancient depression about the size of Connecticut and Rhode Island combined with a 3-mile-high mountain rising from the center of the crater floor.
• Scientists know Gale was once waterlogged. Images from space reveal mineral
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