A manned mission to Mars will push human ingenuity into the next frontier of space exploration, but are the health risks worth it?
When NASA's 30-year Space Shuttle Program ends on Thursday as Atlantis touches down for the last time, space-watchers will be looking toward our next step into space.
We've already 'done' the moon, but Mars still beckons like some interplanetary Brigadoon; visible through the eyes of clever little rovers and orbiters, but just beyond the reach of human footsteps.
Despite several decades of research and development, a long-duration voyage to Mars is still on the drawing board. Putting aside the enormous financial costs of an interplanetary mission, there are still major engineering and physiological hurdles to overcome.