The altitude at which the co-pilot handed control of the plane to his colleague was below the minimum altitude considered safe to continue final descent.

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Besides pieces on the ground, investigators continue to study amateur and government video and photographs of the shuttle, both in orbit and during its final descent.

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"We will get a perspective that no one has seen before, of a spacecraft doing its final descent onto the Mars surface, " said deputy project scientist Ashwin Vasavada.

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Using the most recent determination of UARS' orbit - taken in the early hours of this morning - Dr Eves and a colleague have come up with their own projections of the satellite's final descent.

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Along with Casar, Efimkin and Mikel Astarloza, he had made a decisive break on the final climb, up the Col d'Agnes, then held off the peloton on a long descent to the finish line and fighting it out for the stage win.

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