CAPE CANAVERAL, Fla. - Just before dawn, space shuttle Endeavour, installed on the mobile launcher platform atop the crawler-transporter, is secure on Launch Pad 39B at NASA's Kennedy Space Center in Florida. First motion out of the Vehicle Assembly Building was at 11:57 p.m. EDT April 16. Endeavour will be prepared on the pad for liftoff in the unlikely event that a rescue mission is necessary following space shuttle Atlantis' launch on the STS-125 mission to service NASA's Hubble Space Telescope. After Atlantis is cleared to land, Endeavour will move to Launch Pad 39A for its upcoming STS-127 mission to the International Space Station, targeted to launch June 13.