Scientists give many reasons for going to Mars: to explore, learn new things, find important minerals, maybe establish colonies so people can live there, and search for evidence of past or present life on Mars. The mission will require an extended stay on a frozen planet that lacks breathable oxygen and has only trace amounts of water on its surface.

So far only robots have visited Mars. Robots are safer and cheaper than manned missions. (See our July 1997 WORLD story “A Robot Visits the Red Planet.”) Scientists used to think sending humans would require hauling along three years’ worth of oxygen and water (for the round-trip as well as the time spent on Mars) and enough rocket fuel to get them home. That’s a bulky and expensive way to travel.

However, scientists are studying new ideas that would be less costly and also allow astronauts to “pack light.” Using inflatable habitats, producing oxygen and rocket fuel on Mars instead of lugging it all from Earth, and recycling air and water would all lighten the load.