Space shuttle Endeavour has been rolled out to the launch pad at NASA’s Kennedy Space Center in Florida. NASA says this is likely to be the last time two shuttles are ready to go at the same time.

Endeavour is on stand by in case something goes wrong with shuttle Atlantis’s mission top repair the Hubble Space Telescope. While most shuttle crews can bail out to the International Space Station if something goes wrong, the Hubble mission’s trajectory means the ISS is out of reach (photo detail).

Image: detail photo by from NASA/Kim Shiflett