KENNEDY SPACE CENTER, FL - For what is expected to be the last time in shuttle history, two space shuttles are on two launch pads at the same time as NASA gets ready to launch the final mission to service the Hubble Space Telescope. Endeavour was moved to pad B this morning, joining her sister ship Atlantis already on the adjoining launch pad A.
Today's rollout marks only the 19th time in shuttle program history that both launch pads have been occupied simultaneously. It's also only the fourth time that two stacked space shuttles will be fully visible on the launch pads.
Atlantis was rolled out to Launch Complex 39-A on March 31.
Atlantis is tentatively scheduled to lift off May 12, with Endeavour standing by on the other launch pad ready to mount a rescue mission if Atlantis is damaged during launch or on orbit. If no rescue mission is required, Endeavour will be moved to pad A for launch June 13 on a flight to deliver the final section of the Japanese Kibo science laboratory to the International Space Station.
Atlantis' 11-day STS-125 mission will feature five spacewalks to repair two failed instruments, install three new science instruments, replace the telescope's batteries - the original set - and replace a computer system that failed last year. That failure caused the postponement of the missions original November launch date.