<p>This is a Jan. 10, 2004 file image mosaic taken by the Mars Exploration Rover Spirit's panoramic camera made available by NASA showing a view of Mars southwest of the rover's landing site in the Gusev Crater. 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 quicke…

November 16, 2010