Mission Extended to Fix Thermal Blanket

June 12, 2007 — -- Unsure of what will happen to the Space Shuttle Atlantis when it returns from space if astronauts don't fix the damaged thermal blanket on the orbital maneuvering system pod, NASA officials have decided to schedule a fourth spacewalk and add two days to the STS 117 mission to the International Space Station.

Mission Management Team Chair John Shannon admitted their analysis can't determine how serious the burn through would be if the area is exposed to the searing heat of re-entry.

"We think we are going to have some damage, if we don't go fix this," he said.

Temperatures could range from 700 to 1000 degrees -- not enough to burn through the shuttle's skin, unless the area is exposed to prolonged heating. The length and intensity of that heating is the unknown in this equation.

Shannon would rather not take any chances. With three additional flights scheduled for this year, there is no wiggle room in the schedule for lengthy repairs that would take Atlantis out of flight rotation.

There are only three space shuttles left in NASA's fleet, and the shuttle schedule is packed with 15 flights. NASA doesn't have an open-ended window to finish the space station. The space shuttle will quit flying in July 2010 to allow NASA to focus on returning to the moon, and going on to Mars.

If the OMS pod on Atlantis is damaged underneath the thermal blanket, it will take much longer than normal to turn Atlantis around for its next flight, scheduled in October. The OMS pod contains rockets that help the shuttle maneuver.

Shannon says he would rather have spacewalking astronauts spend a couple of hours to repair the damage on Atlantis in space, than have crews spend months repairing it on the ground.

Teams are still working out the details of the spacewalk to fix the thermal blanket, so no decision has been made yet on whether the attempt will be made during the third spacewalk, or the fourth spacewalk that was just added to the mission.

NASA's Keith Johnson, says his spacewalking team is developing the techniques, working with the tools available to the crew, to choreograph the spacewalk to fix the damaged blanket.