The space shuttle Atlantis took off today at 2:01 toward the Hubble Space Telescope, but there's a second spaceship standing by for a rescue mission NASA hopes it never needs. That ship is the space shuttle Endeavour, which sits atop a launch pad here at NASA's Kennedy Space Center poised for a mission of mercy to rescue the seven astronauts aboard Atlantis if their spacecraft is damaged beyond repair during the Hubble flight.
Atlantis is slated to launch Monday at 2:01 p.m. EDT (1801 GMT) so its astronauts can perform the fifth and final overhaul of the 19-year-old Hubble Space Telescope. With Endeavour also primed for flight, it is the last time ever that both of NASA's shuttle launch pads will be occupied at the same time. But it is also an unprecedented first: It's the only time NASA is launching one shuttle with another on rescue duty. See more here: http://www.nasa.gov/mission_pages/hubble/servicing/SM4/main/index.html