NASA's plan to bring samples from Mars back to Earth is on hold until there's a faster, cheaper way, space agency officials said Monday.

NASA confirmed Monday that a mystery object that crashed through the roof of a Florida home last month was a chunk of space junk from equipment discarded at the International Space Station.

You may have flown a flight simulator in a computer game or at a science museum. Landing without crashing is always the hardest part. But that's nothing compared to the challenge that engineers are facing to develop a flight simulation of the very large vehicles necessary for humans to explore the surface of Mars. The Red Planet poses innumerable challenges to astronauts, not the least of which is getting there.