Universe Today
NASA began the process of moving and juggling space shuttles around for the next mission, the important Hubble Telescope repair mission. Space shuttle Atlantis moved out to launch pad 39A today in preparation for the STS-125 mission, which will send seven astronauts to repair Hubble. Targeted liftoff date is May 12. Additionally, a replacement for the faulty instrument that delayed the mission last fall arrived at Kennedy Space Center, and will be loaded on the shuttle while it's on the pad. This mission will require a second shuttle to be ready for liftoff in the event a problem arises with Atlantis in orbit, and Endeavour will head out to launch pad 39B on April 17. After Atlantis is cleared to land, Endeavour will move to Launch Pad 39A for its upcoming STS-127 mission to the International Space Station, slated to launch in mid-June. Moving a shuttle out to the launch pad takes about six hours, but this video does it in about 3 minutes – so enjoy the sped-up show; it's a nice video showing the process.
Atlantis arrived at Launch Pad 39A at approximately 9:10 a.m. EDT Tuesday on top of a giant crawler-transporter, after leaving the Vehicle Assembly Building at 3:54 a.m. The crawler travels less than 1 mph during the 3.4-mile journey. [/caption] Atlantis' 11-day mission is the final shuttle flight to Hubble. During five spacewalks, astronauts will install two new instruments, repair two inactive ones and replace other Hubble components. Their work will hopefully extend Hubble's life through at least 2014, and give Hubble six working, complementary science instruments with better capabilities.
[caption id="attachment_28314" align="aligncenter" width="317" caption="Screenshot from NASA TV during Atlantis' trip to the launchpad. "]
[/caption] And if you recall, the "rescue" shuttle is necessary because Atlantis will not be going to the International Space Station, nor could it get there if a problem arose because Hubble and the ISS are in different orbits. This has been the policy ever since the Columbia shuttle accident in 2003.
Source:
NASA