Saturday, November 29, 2008

530p 11/29 Update: Lunney outlines shuttle landing strategy


Posted: 5:30 PM, 11/29/08

By William Harwood
CBS News Space Analyst

Changes and additions:

   SR-80 (11/29/08): Astronauts prepare for Sunday landing
   SR-81 (11/29/08): Shuttle heat shield cleared for entry
   SR-82 (11/29/08): Lunney outlines landing strategy


5:30 PM, 11/29/08, Update: Entry flight director hopes for Kennedy landing, but prepared to divert Endeavour to California

Entry Flight Director Bryan Lunney hopes the Florida weather will cooperate and permit the Endeavour astronauts to land Sunday at the Kennedy Space Center. But if predicted high crosswinds and thunderstorms develop, and if Monday's forecast promises little improvement, he'll divert the crew to Edwards Air Force Base in California's Mojave Desert.

"For Sunday, we're going to have KSC and Edwards both called up," he said. "The purpose of that is, since the weather at KSC is not looking so good on Monday and it's not a program impact if we do end up landing over at Edwards, we would be willing to land on Sunday at Edwards if we look at the forecast and determine Monday is not worth waiting for.

"So we'll check the sites out tomorrow morning, I'm not going to commit to either one today, I'm not going to commit until probably as late as I can tomorrow before we decide where to go. Hopefully, KSC weather will be good enough and we can go land there, but if it is bad - and right now, looking at the forecast, we're worried about crosswinds, also we're worried about thunderstorm anvils blowing across and over the landing area - we'll look at Monday, we'll look at Edwards and decide then where to go. Both sites, KSC and Edwards, are fully called up and those folks will be ready to support as needed."

The forecast for Sunday at the Kennedy Space Center calls for scattered clouds at 3,000 and 9,000 feet and overcast at 25,000 feet. Winds will be out of 200 degrees at 16 knots with gusts to 23, producing crosswinds of about 18 knots. The forecast calls for a chance of thunderstorms within 30 nautical miles of the runway.

High crosswinds also are expected Monday, along with a possibly low ceiling. The forecast for Edwards calls for ideal conditions Sunday and Monday.

Endeavour has enough on-board supplies to stay in orbit for several days past Sunday, but only enough lithium hydroxide, the chemical used to remove carbon dioxide from the cabin's atmosphere, to last through Tuesday. Because NASA always tries to preserve the final landing day for unexpected problems with the shuttle, and at least one day for weather wave offs, Lunney has opted to bring Endeavour home Sunday, on one coast or the other depending on the weather.

Based on the forecast from the Spaceflight Meteorology Group at the Johnson Space Center, Sunday is "setting up to look pretty windy on the crosswinds and also the anvils, the big clouds that blow off the top of the thunderstorms," Lunney said. "We expect to see thunderstorms on the western side of Florida and those anvils will blow all the way across the peninsula and could affect us. We don't want to fly through those."

Shuttle commander Christopher Ferguson and his crewmates have four opportunities on successive orbits to return to Earth Sunday, the first two at Kennedy and the second two at Edwards. For the first Florida opportunity, the astronauts would close the shuttle's cargo bay doors around 9:30 a.m. and fire the ship's braking rockets at 12:14 p.m. for a landing on runway 15 at 1:19 p.m.

But once the payload bay doors are closed, the shuttle's radiators are stowed and cooling is provided by boiling water. Because a limited amount of water is available, Lunney said he would not use the fourth and final Edwards opportunity. Once the doors are closed, only three landing options are available: the two at Kennedy and the first of the two at Edwards.

Lunney said a final decision on whether to shoot for the first Florida opportunity might not be made until just before the deorbit rocket firing at 12:14 p.m. If the weather doesn't cooperate, the next opportunity would come with a rocket firing at 1:50 p.m. and a landing at Kennedy at 2:54 p.m. The first Edwards opportunity comes with a 3:20 p.m. EST rocket firing, setting up a landing in California at 4:25 p.m. EST

A detailed deorbit timeline for all the crew's Sunday landing opportunities is available on the CBS News STS-126 Quick-Look page:

Earlier today, the astronauts checked out the shuttle's flight control system and test fired the ship's steering jets. They also launched a small Defense Department satellite to test solar cell technology.

"We completed the flight control system checkout and that system checked out really well, there were no anomalies," Lunney said. "In addition, we did the reaction control system hot fire. We tested all 38 primary RCS thrusters, all of them fired just fine and they're ready for entry as well."

Lunney said a full team of engineers and flight surgeons were standing by at both Kennedy and Edwards and that returning space station flight engineer Gregory Chamitoff, coming back to Earth after six months in space, will be well cared for either way.

"There's a crew of folks who travel out to Edwards, there's a crew of folks who work out there on a regular basis and between all those folks ... they are fully capable of supporting all the orbiter needs once we touch down," Lunney said. "Edwards is fully capable in terms of processing people, experiments, samples and the orbiter."


Quick-Launch Web Links:

CBS News STS-126 Status Reports:

CBS News STS-126 Quick-Look Page:

NASA ISS Expeditions Page:

NASA Shuttle Web:
NASA Station Web:
Spaceflight Now:


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