Welcome home, shuttle Endeavour!
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 21, 2007; Updated at 6 p.m.
"Houston, Endeavour, wheels stopped," commander Scott Kelly radioed as the shuttle rolled to a halt on the centerline of runway 15.
"Roger wheels stopped, Endeavour," astronaut Chris Ferguson replied from mission control in Houston. "Congratulations, welcome home. You've given a new meaning to 'higher' education."
He was referring to teacher-turned-astronaut Barbara Morgan, strapped into a seat on the flight deck just behind the two pilots. Christa McAuliffe's backup in the original Teacher-in-Space program, Morgan waited 21 years to fulfill the legacy of the fallen Challenger astronauts. While she did not teach any lessons from space as McAuliffe once planned, she chatted with school kids during two modest educational events and plans a busy schedule of post-flight appearances to promote science and math education.
Touchdown at 12:32:16 p.m. wrapped up a 5.2-million-mile voyage spanning 12 days 17 hours 55 minutes and 34 second over 201 complete orbits since blastoff Aug. 8 from nearby launch complex 39A. Endeavour's flight now sets the stage for a complex sequence of missions to attach a new docking module to the station in October, followed by the European Space Agency's Columbus laboratory module in December and two flights early next year to attach Japanese modules.
Endeavour made its fiery return to Earth with a small-but-deep gouge in two heat shield tiles on the belly of the ship behind its right main landing gear door. The gouge was caused by a half-ounce piece of foam insulation that fell off an external tank propellant feedline bracket 58 seconds after launch.
NASA managers spent more than half of Endeavour's mission studying the gouge to determine whether it posed any re-entry threat to the shuttle or its crew. Late last week, based on super-computer analysis and tests of a mockup in a furnace that can simulate re-entry heating, NASA's Mission Management Team concluded the damage would have little or no impact and cleared the shuttle for return to Earth as is.
"We agree absolutely 100 percent with the decision to not repair the damage," Kelly said during an in-flight news conference. "We've had shuttles land with worse damage than this. We gave this a very thorough look and I am very, very comfortable and there will be no extra concern in my mind (during re-entry) due to this damage."
Based on close-up video from the runway, the heat of re-entry did no apparent damage to surrounding tiles. The extent of the damage appeared roughly the same, although a gash at the deepest part of the pit looked a bit larger. But there were no other obvious signs of damage and it clearly had no impact on landing.
"There's maybe slightly a little bit more erosion on the, kind of the forward edge, but not too dramatic," said Bill Gerstenmaier, associate administrator for space flight at NASA headquarters. "It didn't get extremely hot and (the underlying material) didn't char. But again, I caution you with this quick analysis we're doing here, the teams will pop these tiles off, we'll take a look to make sure there's no damage, there's nothing going on."
Kelly, pilot Charles Hobaugh, flight engineer Rick Mastracchio, Tracy Caldwell, Al Drew and Canadian astronaut Dave Williams doffed their heavy pressure suits and gathered on the runway for a brief inspection of the shuttle an hour or so after landing. Morgan, feeling a bit woozy as she readjusted to gravity, did not join her crewmates, staying inside NASA's astronaut transporter for post-landing medical checks. All seven astronauts plan to spend the night in Florida before flying back to the Johnson Space Center in Houston on Wednesday.
"The flight was absolutely wonderful," Morgan, 55, told reporters five hours after landing. "I'm really proud of our whole team and the team on the ground. ... it all worked out really, really well I thought. How did I do? It took me a little while at first to get used to microgravity, it took a couple of days, and the first day - and I think this was the biggest surprise of all - I felt I was upside down the entire first day. It wasn't a bad feeling, it was just an unusual feeling."
Asked how she felt after landing, Morgan said: "The room still spins a little bit, but that's OK."
"What I really want to do is take what this experience was and figure out how we can do a better job to help serve our students and our teachers in a way they want that will be more helpful to them," Morgan said. "And I would love to figure out how we can make more and more of these opportunities available for more and more of our teachers."
A bracket redesign already was in work, scheduled to debut on a tank four missions from now. The question facing NASA is what to do about the next three flights, currently scheduled for launchings Oct. 23, Dec. 6 and Feb. 14.
Shuttle Program Manager Wayne Hale said Monday it's too soon to say what impact work to recover from Endeavour's unexpected foam debris incident might have on the upcoming schedule. But Gerstenmaier said today that at this point, major delays do not appear to be in the cards.
"We're still pointed toward Oct. 23," Gerstenmaier said. "We have a meeting today going on to have a look at the tank to see if there's anything we want to do in terms of modifying the tank ... or we leave it the way it is and head for Oct. 23. But I think we're still clearly focused on the next mission and we're ready to move forward."
From the local processing perspective, "it really and truly depends on how long we need to do the analysis for the repair if it turns out to be necessary or not," said Launch Director Mike Leinbach. "We were going to mate the external tank (and boosters) yesterday for the next mission, so we're in kind of a holding pattern here. We've got several days to work with, so we're in no immediate danger of delaying the next mission at all, that's certainly not in the cards. We have some time in the schedule to make up as we go along. So it's going to depend on the results of the study, whether we need to do a fix or not, how long we take to do that fix and then what that would translate into for (processing)."
Hale said engineers are working on "five different options to improve the situation on the next tank. We will expect there will be some readjustment to our schedule as we work through those options. However, I believe that based on the discussions we've had, that our impacts to the next flight in terms of the actual launch date of Oct. 23 will be small, we think we have plenty of time to evaluate some changes and in fact implement them if we feel that they are well justified."
At NASA's traditional post-landing news conference, NASA Administrator Mike Griffin showed off spectacular post-undocking pictures of the international space station, calling the unfinished lab complex "one of the great accomplishments of mankind."
"We're building a space station here, one flight at a time, and while I appreciated the media's attention on the ding in the tile, actually the orbiter overall was really pretty clean," he said. "We had one kind of ugly ding and we paid appropriate attention to it. I would have liked to have seen some media attention on what a magnificent accomplishment we're undertaking here. I think we're doing pretty well with it."
Endeavour docked with the space station Aug. 10 and the next day, the astronauts installed a short spacer segment on the right end of the station's main solar power truss. Two days later, Mastracchio and Williams replaced a faulty stabilizing gyroscope on the station amid work to transfer 5,000 pounds of equipment and supplies to and from the lab complex. The astronauts used robot arms on the shuttle and space station to attach a 7,000-pound equipment storage platform to the solar array truss and staged a third spacewalk Aug. 15 to complete a variety of station assembly get-ahead tasks.
Endeavour is the first shuttle equipped with a new station-to-shuttle power transfer system that enabled the orbiter to plug into the space station's solar power grid. As a result, NASA managers extended the flight three days and added a fourth spacewalk. Originally scheduled for last Friday, the excursion was delayed one day while NASA managers debated whether to turn the excursion into a tile repair spacewalk.
In the end, a repair was deemed unnecessary and Williams and space station flight engineer Clay Anderson were cleared to carry out the originally planned EVA on Saturday. But the threat of Hurricane Dean raised the possibility flight controllers at the Johnson Space Center might have to evacuate. As a result, NASA managers shortened Saturday's spacewalk and moved undocking from Monday to Sunday to get Endeavour back on the ground today.
As it turned out, Dean never threatened the Texas coast but by that point NASA was committed and the crew returned to Earth today.
Flying backward over the Indian Ocean at a velocity of 5 miles per second, Kelly and Hobaugh fired Endeavour's twin braking rockets at 11:25 a.m. for three minutes and 33 seconds, slowing the ship by 246 mph and lowering the far side of its orbit into the atmosphere. A half-hour later, the shuttle fell into the discernible atmosphere at an altitude of 76 miles. At that point, Endeavour was 5,020 miles from touchdown.
The shuttle's ground track carried it high above Central America just west of the Panama Canal on a course carrying it across central Cuba and up the Florida peninsula to the Kennedy Space Center.