NASA's Kepler spacecraft enclosed in a canister and protective cover travels at Cape Canaveral Air Force Station.

NASA's Kepler spacecraft, enclosed in a canister and protective cover, travels by truck to Launch Pad 17-B at Cape Canaveral Air Force Station. The liftoff of Kepler aboard a Delta II rocket is currently targeted for 10:48 p.m. EST March 5 from Pad 17-B. Kepler is designed to survey more than 100,000 stars in our galaxy to determine the number of sun-like stars that have Earth-size and larger planets, including those that lie in a star's "habitable zone," a region where liquid water, and perhaps life, could exist. If these Earth-size worlds do exist around stars like our sun, Kepler is expected to be the first to find them and the first to measure how common they are. Photo credit: NASA/Jack Pfaller