Anyone who steps onto Mars will be crossing a one-way threshold in more ways than one. The physics of getting there and back, the biology of living in low gravity, and the psychology of leaving Earth ...

Why Ellen DeGeneres and Portia de Rossi, Eva Longoria, Lindsay Lohan and more celebrities desired a change from the Hollywood ...

The last time a crew of Americans rode a rocket toward the Moon, the country was reeling from assassinations, riots, and a ...