Asteroids May Be Tougher Target Than Mars for Manned Missions

Though asteroids are viewed as stepping stones in NASA's manned march to Mars, sending humans to a space rock may actually be a bigger challenge than putting boots on the Red Planet.

Mars is farther away than any near-Earth asteroid that NASA would target, but this disadvantage may be outweighed by the greater knowledge scientists have gained of the Red Planet thanks to the many Mars missions that have launched over the years, experts say.

Further, mapping out an asteroid mission is nearly impossible at this point, since NASA does not yet know where it's going.

"There are still no good asteroid targets for such a mission, a necessary prerequisite for determining mission length and details such as the astronauts’ exposure to radiation and the consumables required," states a December 2012 report from the U.S. National Research Council (NRC).

http://www.space.com/19633-nasa-asteroid-mars-manned-missions.html?cid=dlvr.it