A spacecraft now completing a nine-month journey from Earth to Mars must survive a fiery, risky descent to the Red Planet to have a chance to scoop up water ice believed buried under an arctic plain.
After traveling 422 million miles since its launching last Aug. 4, NASA’s Phoenix Mars Lander is aiming for a touchdown on Sunday in the unexplored northern regions of Mars. But first, it must survive what its developers call the final “seven minutes of terror” to reach the surface.
“There are many, many risks and uncertainties,” said Dr. Edward Weiler, associate administrator of the National Aeronautics and Space Administration science division. Since the start of planetary exploration, 55 percent of spacecraft sent to land on Mars have failed, he said.
Although the Phoenix lander, a conglomeration of parts from two earlier failed missions, has been tested and rechecked to correct all known design flaws and potential errors, Dr. Weiler said, “there are always the unknown unknowns.”
NYTimes-
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