Pad workers remove the protective cover from the metal transportation canister around NASA's Kepler spacecraft.

In the mobile service tower on Launch pad 17-B at Cape Canaveral Air Force Station in Florida, workers remove the protective cover from the metal transportation canister around NASA's Kepler spacecraft. The spacecraft was mated with the Delta II rocket for launch. The liftoff of Kepler is currently scheduled for 10:48 p.m. EST March 5. 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