CAPE CANAVERAL, Fla. (AP) — NASA's newest Martian explorer is on its launch pad in Florida, ready to soar.
The Maven spacecraft was scheduled to blast off aboard an unmanned Atlas V rocket Monday afternoon.
NASA is sending Maven to Mars to study its upper atmosphere. Scientists want to know why Mars went from being warm and wet during its first billion years, to the cold and dry place it is today.
The early Martian atmosphere was thick enough to hold water and possibly support microbial life. But much of that atmosphere may have been lost to space, eroded by the sun.
"Something clearly happened," the University of Colorado's Bruce Jakosky, the principal Maven scientist, said on the eve of Maven's flight. "What we want to do is to understand what are the reasons for that change in the climate."