FILE - In this file image provided by NASA's Hubble Space Telescope a close-up of the red planet Mars is shown. Two scientists are proposing we send volunteers to Mars and leave them there. They say ... more 
FILE - In this file image provided by NASA's Hubble Space Telescope a close-up of the red planet Mars is shown. Two scientists are proposing we send volunteers to Mars and leave them there. They say the mission would mark the beginning of long-term human colonization of Mars, with numerous follow-up trips. The colleagues contend one-way missions could happen a lot quicker and cheaper, and it is essential to begin colonizing another planet as a hedge against a catastrophe that makes Earth uninhabitable. less 
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Associated Press | Photo By NASA, File
Thu, Nov 18, 2010 5:01 AM EST