Endeavour Rollout Images from this Morning

8:15 am EDT: Endeavour under a blue sky at pad 39-B with the GO2 vent hood parked over the Tank in this updated image via NASA-TV.

Endeavour is shown in several NASA-TV still shots as she inched closer to the top of launch pad 39-B this morning between 6:30 and 7:01 am EDT.

Endeavour begins Trip to Launch Pad 39-B

The space shuttle Endeavour began her trip out to her seaside launch pad at midnight this morning to prepare for her flight on one of two missions - a shuttle emergency rescue flight or a space station construction and servicing mission.

First motions from the massive vehicle assembly building began at 12 midnight, with the entire shuttle stack beginning it's ride at about 1 mph down a gravel road to launch pad 39-B.

Meanwhile, over at pad 39-A, shuttle Atlantis sits awaiting her next flight on May 12th to repair and upgrade the Hubble Space Telescope. Because Hubble is in a different orbital inclination (28.45 degrees to the equator) than the space station is (51.65 degrees), Atlantis could not get over to the station if she was damaged while on orbit. Damage coming from foam falling off the external tank and smashing the belly of Atlantis - such was the case of the doomed shuttle Columbia in 2003.

Post-Columbia rules dictate the need of having a back-up shuttle ready to go if an orbiter is damaged while in space. Atlantis STS-125 mission in May will be the final non-space station flight of the shuttle program. Read our background story on how the emergency rescue mission would work.

Between today and through Atlantis' mission, Endeavour will be prepared for the mission no one wants - STS-400. Near the end of Atlantis' 11-day flight, shuttle program managers will give the green or red light following on orbit crew inspections of the thermal tiles which surround the belly, wing leading edges and nose section.

If everyone is comfortable that Atlantis is healthy, then Endeavour will begin her move from pad 39-B south to Pad 39-A, and begin preperations for the much wanted STS-127 mission to the international space station.

Once Endeavour departs pad B, then ground crews will begin full scale work to prepare the northern pad for the first Ares 1X unmanned rocket test launch in late August.

Endeavour: Rescue Mission STS-400 Planned

In a few days, the space shuttle Endeavour will rollout to her ocean side launch pad right next to where her sistership Atlantis currently sits, to prepare for a possible rescue flight following Atlantis launch into space.

In the event that Atlantis' thermal tiles on her outerskin are damaged during her STS-125 launch and Mission Control states that reentry would be too risky, Endeavour would be called up on rescue mission STS-400.

STS-400 would see Endeavour launch with a crew of four from launch pad 39-B and into the same orbital inclination as Atlantis - 28.45 degrees to the earth's equator. After only one day of manuvers to catch up with the weakened Atlantis, Endeavour would slowly pull up and park her payload bay over her weakened sistership.

NASA's Shuttle Program Managers stated that Endeavour's 50-foot robotic arm would then latch Atlantis robotic arm so that both ships are then connected to begin crew rescue via spacewalks. Program managers also state that only the STS-125 crew of seven would spacewalk over to Endeavour's outside airlock during the span of several days.

Atlantis' spacewalking astronauts of John Grunsfeld and Andrew Feustel will depart Atlantis to prepare a rope which will assist fellow astronaut Megan McArthur over to Endeavour. The following day more of the crew will translate over concluding with Atlantis' skipper Scott Altman.

A few months ago, the Johnson Space Center said that the STS-400 crew would be made up of the commander, pilot, and two mission specialists from a recent space station mission - last November's STS-126 mission. Chris Ferguson would command STS-400, with pilot Eric Boe and mission specialists Robert Kimbrough and Stephen Bowen rounding out the crew.

A few days following Atlantis' May 12th launch, the STS-125 crew will use the robotic arm to survey the orbiter's tiles and thermal blankets along her wing leading edges, nose section and aft section. If issues with damaged tiles are seen, then two spacewalkers will venture outside to see if the damage can be repaired using an in flight maintenance kit.

If Atlantis is cleared for reentry, then Endeavour will be moved from Pad 39-B southward to Pad 39-A to be prepared for her prime mission STS-127 to the international space station.

Inside NASA, everyone we spoke with states that if Atlantis is deemed a loss while on orbit, it could mean the end of shuttle flights now instead of Autumn 2010 - the time when the shuttle fleet are set to retire.