Space shuttle Endeavour moved to launch pad to rescue Atlantis?

In an unprecedented step, a space shuttle was moved to the launch pad Friday for a trip NASA hopes it will never make - a rescue mission. The shuttle Endeavour is on standby in case the seven astronauts who go up on Atlantis next month need a safer ride home.

Atlantis and its crew are headed into space for one last repair job on the 18-year-old Hubble Space Telescope. It's a venture that was canceled when first proposed a few years ago because it was considered too dangerous.

The risk is this: If Atlantis suffers serious damage during launch or in flight, the astronauts will not be at the international space station, where they could take refuge for weeks while awaiting a ride home. They would be stranded on their spacecraft at the Hubble, where NASA estimates they could stay alive for 25 days. Air would be the first to go.

Endeavour and four more astronauts would need to blast off on a rescue flight as soon as NASA determined Atlantis was too damaged to fly home.

On Friday, Endeavour was parked at its launch pad just a mile from where Atlantis is tentatively set to lift off on Oct. 10.

It is the first time since 2001 - when flights were more closely spaced - that both of NASA's shuttle pads have been occupied. And it will probably be the last.

The Atlantis astronauts say there's a slim chance any rescue will be needed, and they say they would fly to Hubble even if there were no such backup plan.

Scott Altman, Atlantis' commander, said it may seem like overkill, but having a rescue ship on the pad is the right thing to do. - ap