NASA studies landing options as hurricane threat looms
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: August 17, 2007;
Updated at 8:20 p.m. with MMT decision to protect option of landing Tuesday;
Updated at 9 p.m. with 'big picture' words sent to crew
NASA's Mission Management Team, after resolving concerns about damage to the shuttle Endeavour's heat shield, shifted gears today and began discussing the possibility of bringing the astronauts back to Earth on Tuesday, a day early, because of concern Hurricane Dean could threaten a shutdown of mission control at the Johnson Space Center in Houston.
"The current forecast for the storm would have the eye of Dean in the center of the Gulf area sometime on Wednesday," said LeRoy Cain, co-chairman of NASA's Mission Management Team. "If you back up from there to look at evacuation plans, not only for Johnson Space Center but for surrounding areas here, our history from previous hurricanes and storms tells us we really have to start letting our personnel go and take care of themselves and their families in the Sunday kind of time frame, if not sooner.
"And so, we began to look at this and determined we would really like to protect an option to be able to end the mission on Tuesday," he said. "From an institutional standpoint, the center will have to make a decision sometime in the mid-Sunday to mid-Monday time frame as to whether or not to close the center, and if so, when will they close? For a storm that's headed for the Houston area, in all likelihood the center would look at closing sometime on the second half of Monday-to-certainly-by-Tuesday timeframe. ... So we factored all that in and determined we would really like to protect an option to land on Tuesday."
The Endeavour astronauts plan to carry out a fourth and final space station assembly spacewalk Saturday and finish up equipment and supply transfers to and from the lab complex Sunday. Hatches between Endeavour and the station are scheduled to be closed Sunday night to set the stage for undocking Monday. A now-routine post-Columbia final heat shield inspection will be carried out Monday afternoon and the crew will pack up and test the shuttle's re-entry systems Tuesday. Touchdown at the Kennedy Space Center is targeted for around 12:52 p.m. Wednesday.
But plans are being put in place to close hatches between Endeavour and the space station Saturday night to permit an undocking Sunday and landing Tuesday depending on Dean's eventual track. Astronaut Shane Kimbrough called the crew from mission control late Friday to explain the discussion.
"Endeavour and station on the big loop with big picture words," he radioed from Houston. "Due to Hurricane Dean and its potential impact to the Gulf Coast, we're working towards a plan that would land us a day early. The way we're going to get there is to give up some transfer activities tomorrow and possibly shorten EVA-4. That will allow us to close the hatches tomorrow night and then we'll undock on Sunday and land on Tuesday. We're working the timeline really hard down here as you might imagine, we'll have a detailed plan for you in the morning."
Mission control commentator Kyle Herring said no final decisions about landing Tuesday had been made, but there are "a number of items that protect for that option and those were relayed up to the crew, which basically focuses on the duration of the ... spacewalk tomorrow by Dave Williams and Clay Anderson."
The problem for NASA is the pace of Hurricane Dean, the time needed to complete normal mission work and when decisions would have to be made in advance of Dean's arrival in the Gulf of Mexico. The concern, in part, is the risk associated with controlling a flight from a backup mission control center in Florida with fewer engineers, and less computer processing power, to monitor the shuttle's myriad systems.
"There are two parts to the emergency mission control center activation," said shuttle flight director Matt Abbott. "One is you take a team of controllers and send them to KSC and have them set up and be there on standby and ready to take over if that becomes necessary. So that can be done as a precaution, just like we can do the same thing with the backup control center advisory team activities on the station side.
"But ... we have a lot more limited insight into the vehicle systems, or at least less people to monitor that insight into the vehicle systems. We do have the capability to keep things going and to get the vehicle on the ground safely, but again, when you look at the effort and the number of people we have involved in a mission and a landing here and then you skinny that down to a couple of dozen people, there is obviously an element of additional risk because you're not able to do all the things you used to be able to do here in Houston. So that's really it in a nutshell."
While controlling a shuttle from Kennedy is part of a long-established contingency plan, "the systems and facilities down there are set up to get vehicles launched and off the pad and the activities we do here (in Houston) are a little bit different," Abbott said. By moving landing up a day, NASA likely could ensure a normal JSC-controlled re-entry.
But to land Tuesday, if it came to that, the Endeavour astronauts would have to finish equipment transfers Saturday, during and immediately after the spacewalk, and close hatches between the two spacecraft Saturday night. The crew then could undock Sunday and have the normal two days to carry out a final heat shield inspection, test the ship's re-entry systems and pack up for landing.
Cain said senior managers planned to meet late Friday to prioritize the activities planned for Saturday's spacewalk. Because most of the work is made up of relatively low-priority "get-ahead" tasks that could be deferred with no major impact on station assembly, mission managers may opt to shorten the spacewalk to make it easier for the crew to complete the tasks required before the hatches would be closed.
At the same time, NASA managers are putting lists of key personnel together and determining what would be necessary to activate all three shuttle landing sites - the Kennedy Space Center, Edwards Air Force Base, Calif., and White Sands Space Harbor, N.M. - on Tuesday.
Space station controllers also are reviewing contingency plans for moving key flight personnel to a backup site in Texas. If Hurricane Dean shuts down the Johnson Space Center, the flight control team could route commands through Russian ground stations as required.
"It's really too early to say exactly how this is all going to play out," said Abbott. "We've got options that we're looking at, we're trying to lay all those out so we know exactly what our capabilities are and what we have available to us."
For the record, the shuttle has enough on-board supplies to remain in orbit until next Friday with two days beyond that held in reserve as always to handle major systems problems or bad weather.
Earlier today, the astronauts held their traditional in-flight news conference and shuttle commander Scott Kelly fielded a variety of questions about the health of the shuttle's heat shield and his comfort level with a management decision to forego a spacewalk repair job.
"We agree absolutely 100 percent with the decision to not repair the damage," Kelly said during an in-flight news conference. "There was a lot of engineering rigor put into making this decision, it took some time but that was because there was a lot of testing going on, arc jet testing in particular that took some time to get done. ... With the damage that we have, the maximum temperature (the shuttle's aluminum skin) will see is 340 degrees. The failing point of aluminum, I think, is somewhere over 1,000 degrees. So even though a repair could potentially provide a little bit more margin, there is certainly more risk in doing the repair than we're willing to take. We were certainly concerned that if we did the repair we could potentially cause more damage to the underside of the orbiter. Since a repair was not really warranted based on the data and the testing, the shuttle crew and the station crew, actually, agreed with the decision not to do the repair."
He said work to resolve the issue "was a very, very rigorous process" and "I for one am happy it took as long as it did."
"They delayed our fourth EVA a day to give themselves more time so they wouldn't be pressed by the schedule," he said. "If it had turned out the MMT decided we needed to do a repair, we could have done it tomorrow. ... So I think it was absolutely the right decision to forego the repair and I think they took the appropriate amount of time to come to that conclusion. I would have been a little bit more nervous if they had just looked at the data we provided in the focused inspection (last Sunday) and say you know, either we had to repair it or we didn't. This is a very complicated process and it takes time to complete. We are absolutely behind the MMT, we think they made absolutely the right decision."
Asked if he thought entry might be a bit more tense for the crew because of known damage to the heat shield, Kelly said "I personally do not. 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 due to this damage."
Added pilot Charles Hobaugh: "I totally agree with Scott. I don't think there's anything really to concern us. John Young (commander of the first shuttle mission) used to always sit in our Monday morning meetings and talk about all the tiles that fell off of STS-1 and how they made it back fine. So I don't think it's really an issue and I think it was a great decision."