Space Elevator?

First, a shout-out to reader Imperator D, who turned me on to this idea with his comment about a previous blog on the question of whether NASA should go back to the moon or straight to Mars. Imperator wrote that

“The priority for low and high orbit human endeavors is to build a space elevator. This would make construction of a large vessel easier.”

Sounds perfectly logical, huh? Except that you may be wondering: What in the Robert Heinlein is a space elevator? 

Allow me to explain. For most of the space-faring era, humans have relied upon powerful rockets to put satellites, probes and manned spacecraft into space. The Space Shuttle, for example, is propelled at liftoff by a pair of 650-ton solid rocket boosters that are jettisoned, retrieved and refilled with fuel for reuse in a future mission. For the next generation of missions to the moon and beyond, NASA is developing the massive Ares V cargo launch vehicle, which it hopes to have in ready in time for a manned lunar mission in 2020.