CAPE CANAVERAL, Fla. – On the runway at the Shuttle Landing Facility, or SLF, at NASA's Kennedy Space Center in Florida, the Shuttle Training Aircraft is ready for takeoff. STS-125 Commander Scott Altman and Pilot Gregory C. Johnson are practicing shuttle landings on the SLF runway in preparation for their launch on space shuttle Atlantis, scheduled for 2:01 p.m. EDT on May 11. On Atlantis’ STS-125 mission, NASA's Hubble Space Telescope will be serviced for the fifth and final time. The flight will include five spacewalks during which astronauts will refurbish and upgrade the telescope with state-of-the-art science instruments. As a result, Hubble's capabilities will be expanded and its operational lifespan extended through at least 2014. Photo credit: NASA/Kim Shiflett