Space shuttle Atlantis cleared for launch next week
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: November 30, 2007
NASA managers today cleared the shuttle Atlantis and its crew for blastoff Dec. 6 on a long-awaited flight to attach the European Space Agency's Columbus research lab to the international space station.
With commander Steve Frick and pilot Alan Poindexter at the controls, Atlantis is scheduled to lift off from pad 39A at the Kennedy Space Center at 4:31:44 p.m. next Thursday, roughly the moment when Earth's rotation carries the launch pad into the plane of the space station's orbit.
"We have had three outstanding flights of the space shuttle so far this year and we're looking forward to a fourth," shuttle Program Manager Wayne Hale told reporters late today. "Atlantis is on the pad, ready to go, no major issues or concerns regarding that vehicle.
"We are looking at Discovery, having just come back from its last mission in almost pristine shape, really good condition. And looking ahead into February, you saw the external tank delivered here today to the Kennedy Space Center (for the next mission) and processing on Endeavour is going very well.
"So all in all, the hard work of a large number of folks is really beginning to pay off," Hale said. "We had a full and frank flight readiness review today, it was a great review, we laid a lot of things out on the table and at the end of the day everyone was comfortable that we're ready to go fly."
NASA will only have a week or so to get Atlantis off the ground before the launch window closes due to temperature constraints related to the station's orbit. If the shuttle isn't off by Dec. 13, the flight will slip to early January.
At the nearby Cape Canaveral Air Force Station, meanwhile, United Launch Alliance is preparing an unmanned Atlas 5 rocket for takeoff Dec. 10 to boost a classified National Reconnaissance Office satellite into orbit. While no final decisions have been made, that flight likely would slip a few days if Atlantis doesn't get off on time to avoid a potential conflict.
Frick, Poindexter, flight engineer Rex Walheim, Leland Melvin, Stan Love and European astronauts Hans Schlegel and Leopold Eyharts, a French air force general, plan to attach the Columbus module to the newly installed Harmony module's right-side port on Dec. 9, the day after docking.
Three spacewalks are planned, two by Walheim and Schlegel and one by Walheim and Love, to connect and outfit Columbus, to replace a nitrogen tank used to pressurize the station's ammonia coolant system and to move a faulty gyroscope back to the shuttle for return to Earth.
In addition to delivering Columbus, Atlantis also will ferry Eyharts to the station. The European Space Agency astronaut, veteran of a three-week stay aboard the Russian Mir space station in 1998, will replace Expedition 16 flight engineer Dan Tani aboard the ISS. Tani will return to Earth in Eyharts' place aboard Atlantis.
"We all come into these space shuttle flights looking at the big element in the payload bay and waiting for the action when we actually install it," said station Program Manager Mike Suffredini. "This flight and the following stage and multiple stages after that will be an extra challenge for us.
"We have been working with our Russian counterparts and our Canadian counterparts for the better part of about seven years and in all that time, we evolved in our operations capability, how we work together. And now we're bringing on another partner, multiple countries, multiple control centers to operate this Columbus module.
"So the very small part you'll see during the docked operations of installing the Columbus module really will just be the tip of the iceberg as we work together in a partnership and move on into the next couple of flights," Suffredini said. "By April, we'll have the (Japanese modules) up and we'll have yet another partner in operation with us. So it's a very exciting time for us in the ISS program."
As it currently stands, Atlantis will land back at the Kennedy Space Center around 12:29 p.m. on Dec. 17. But depending on when Atlantis actually takes off, and how much oxygen and hydrogen are available to power the ship's electricity producing fuel cells, NASA managers may extend the mission by two days and add a fourth spacewalk.
The goal is to conduct an additional inspection of the station's right-side solar array rotary joint to help determine the source of metallic contamination in the mechanism.
The space station is equipped with two solar alpha rotary joints, or SARJs, one on each side of the lab's main power truss. The SARJ joints rotate outboard solar arrays like giant paddle wheels as the station circles the planet, keeping the blankets face-on to the sun to maximize electrical output.
Each joint features two redundant 10-foot-wide gear/race rings and two drive motors, only one of which is engaged at any given time. Twelve so-called trundle bearing assemblies are positioned around one of the two gear races to allow smooth rotary operation.
The left-side SARJ is rotating normally, but earlier this fall flight controllers noticed unusual vibration and slightly higher current levels in the right-side SARJ. Tani, who was ferried to the station aboard the shuttle Discovery last month, looked inside the joint behind thermal panel No. 12 during an already planned spacewalk Oct. 28.
He spotted metallic contamination and collected samples using adhesive tape. Those samples later were determined to be made up of race ring material. At that point, mission managers decided to lock the starboard SARJ in place to prevent additional damage.
During a second inspection by Tani during a spacewalk Nov. 24, additional contamination was spotted. In a worst-case scenario, the 12 bearing assemblies and two drive motors could be moved to the redundant gear during three to four spacewalks. But engineers do not want to consider such a drastic step until they figure out what is causing the problem with the active gear and race ring.
If a fourth spacewalk ultimately is approved for the Atlantis mission - and no such decision will be made until after launch - Love and Tani would carry out a more detailed inspection of the mechanism's drive motor, bearings and the bearing race ring now known to be damaged.
"With some power downs, we can get a couple of extra days," said Suffredini. "So if everything goes well and we get a couple of extra days, we would attempt an EVA 4. And during an EVA 4, we would do a thorough inspection of the entire joint. We would take samples, we would remove many of the (thermal) covers. We'd like to remove them all, we're not sure we can do that in the EVA so we have a priority.
"We'll remove all the covers that will reveal all the trundle bearings, we'll remove the covers that will reveal the drive (motors), we'll inspect that, we'll take samples all the way around, we'll look with a mirror so we can see the under part of the race. And we'll take a number of photographs and then we'll retrieve one of the 12 trundle bearings. We have one selected, but if in our inspections we find one that really stands out we could choose to take that one.
"Our analysis says we can operate the joint on 11 of 12 trundle bearings and we believe that the data we could glean from one of the trundle bearings bringing it home is worth the effort. ... So that's the plan, assuming we can get the extra two days."
Suffredini said the station can safely operate with the right-side SARJ locked in place through launch of two Japanese research modules in February and April. But at some point next spring, NASA needs to get the joint rotating again, either with a repair or using different operating procedures.
Preparing for a variety of possible repair options, Atlantis' crew will carry up a new drive motor. Ten to 12 new trundle bearings will be ferried to the station aboard Endeavour in February.