Space shuttle Atlantis atop the mobile launcher platform straddles the flame trench on Launch Pad 39A at NASA's Kennedy Space Center in Florida. Behind it is the Atlantic Ocean. Atlantis has been joined by space shuttle Endeavour on Launch Pad 39B. This is probably the final time two shuttles will be on launch pads at the same time with the space shuttle fleet set for retirement in 2010. 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. Photo credit: NASA/Dimitri Gerondidakis