Endeavour departs station after successful visit
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 19, 2007
The Endeavour astronauts undocked from the international space station today and carried out a final inspection of the shuttle's carbon composite nose cap and wing leading edge panels to make sure the ship is ready for re-entry and landing Tuesday to close out a dramatic station assembly mission.
"Undocking, in a word, really was flawless, it was completely by the book, absolutely picture perfect," said lead flight director Matt Abbott. "Looking ahead to tomorrow, the crew wakes up at 3:30 a.m. (Central Time). It'll be pretty much a standard end-of-mission-minus-one day, with reaction control system hotfire checks and the flight control system checkout activities and cabin stowage. Tuesday is now our planned landing day.
Forecasters are predicting generally good weather at the Kennedy Space Center and at NASA's favored backup landing site, Edwards Air Force Base, Calif.
"KSC weather permitting in Florida, the plan is to go into KSC on Tuesday and of course, we do have some extension days beyond that, weather permitting here in Houston as we continue to watch the track of Hurricane Dean."
NASA originally planned for Endeavour's crew to undock Monday and land Wednesday. But a fourth and final spacewalk was cut short Saturday and the crew was ordered to undock and land a day early because of the possibility Hurricane Dean could force flight controllers to evacuate the Johnson Space Center in Houston. While NASA has contingency plans in place to control a shuttle flight from Kennedy, engineers would not enjoy the normal staffing levels and computer processing power. Moving landing up one day, NASA hoped to ensure normal mission control operations for at least one landing opportunity.
Because of the possibility of an evacuation later in the week, mission managers decided over the weekend to staff all three shuttle landing sites Tuesday - Kennedy, Edwards and White Sands Space Harbor, N.M. If JSC was threatened, the plan was to bring Endeavour down at one of those sites.
But Hurricane Dean is now tracking well south of Houston, an evacuation is not imminent and with good weather expected in Florida and California's Mojave Desert, mission managers today dropped White Sands from their landing plan.
"The latest track from the National Hurricane Center is favorable for the Johnson Space Center," said John Shannon, chairman of NASA's Mission Management Team. "It looks like it'll be passing by Jamaica today and heading for the Yucatan Peninsula and then into central Mexico. There is still uncertainty with a storm like this, but right now it's looking pretty good from our standpoint. The Johnson Space Center will be open for normal operations tomorrow. ... We will meet again tomorrow but the threat is certainly somewhat less than it was the last two days."
As a result, he said, "we're not going to execute any of those (contingency) plans right now. We're just going to wait. There's not going to be a change to the flight control team manning, we're not going to be sending people out to Florida right now, we're going to stand by a little bit.
"We'll come in tomorrow and we'll talk about the hurricane, we'll talk about the weather at the landing sites," Shannon said. "I think for Monday, we would probably leave all of our support for Edwards and for the Kennedy Space Center in place and then on Tuesday, we'd be one day smarter on where the hurricane is really going. It's possible Tuesday morning we would end up not exercising an Edwards option if the Kennedy Space Center was not go and end up going around to Wednesday to try and get into the cape."
Here are updated deorbit and landing times for Tuesday, Wednesday and Thursday at the Kennedy Space Center and Edwards Air Force Base (in EDT):
ORBIT.SITE..DEORBIT....LANDING Tuesday, 08/21/07 201...KSC...11:25 AM...12:32 PM 202...KSC...01:00 PM...02:06 PM 203...EDW...02:30 PM...03:37 PM 204...EDW...04:06 PM...05:11 PM 205...EDW...05:43 PM...06:48 PM Wednesday, 08/22/07 217...KSC...11:52 AM...12:54 PM 218...KSC...01:27 PM...02:29 PM 219...EDW...02:57 PM...03:59 PM 220...EDW...04:33 PM...05:35 PM Thursday, 08/23/07 232...KSC...10:40 AM...11:42 AM 233...KSC...12:15 PM...01:17 PM 234...EDW...01:45 PM...02:47 PM 235...EDW...03:20 PM...04:22 PM 236...EDW...04:57 PM...05:58 PM
"We've got two more days to go in the mission, so it's not over yet," Abbott said. "We've got to stay focused, but we're looking forward to a safe and successful couple of days and then an entry and landing on Tuesday."
Endeavour undocked from the international space station today at 7:56 a.m. as the two spacecraft sailed 210 miles above the south Pacific Ocean.
"Physical separation, Houston," one of the shuttle astronauts radioed as powerful springs pushed the two spacecraft apart.
As the shuttle slowly pulled away directly in front of the lab complex, station commander Fyodor Yurchikhin radioed: "Endeavour, from ISS. Endeavour departure." Following naval tradition, he then rang the ship's bell in the Destiny laboratory module.
"Thanks for everything, Scott and the Endeavour crew," station flight engineer Clay Anderson said to shuttle commander Scott Kelly. "Godspeed, I was proud to be a part of STS-118."
"And Endeavour, have a good landing," station flight engineer Oleg Kotov radioed.
"And to the ISS crew, we couldn't have gotten everything we accomplished without you guys," Kelly replied. "We look forward to seeing you back on planet Earth."
Endeavour pulled away to a distance of about 400 feet in front of the station before looping up and passing directly above it. From there, the shuttle fell behind and slowly left the immediate area.
With undocking complete, the major item on the crew's agenda today was a final heat shield inspection to make sure Endeavour's reinforced carbon carbon nose cap and wing leading edge panels have not suffered any damage from orbital debris or micrometeoroids since a similar inspection was carried out the day after launch.
No obvious damage was visible in downlinked television views of the survey, but it will take engineers a full day to assess the data and make a final determination.
"Just about every flight, we do see MMOD (micrometeoroid/orbital debris) damage on the wing leading edge and nose cap," Shannon said. "They're very small scrapes, very small pits in the silica carbide gray outer layer, but not down to the carbon. Matter of fact, I think on the last flight we had 17 small indications. Post flight, they go over it with high magnification and look for anything like that. That is just a function of flying in space. You have very small particles that can impact you. It would take a fairly significant one to affect us but it's not a zero probability, that's why we do the late inspection."
Impact sensors mounted directly behind Endeavour's leading edge panels have recorded 16 events corresponding to shocks ranging in strength from 0.5 to 2 Gs. Similar shocks have been recorded on previous post-Columbia shuttle flights. Engineers believe the events may be associated with thermal stress as the shuttle's structure responds to changes in temperature.