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NASA Mulls Spacewalk Repair for Shuttle Tile Damage

By Tariq Malik

Staff Writer

posted: 12 August 2007

7:42 p.m. ET

HOUSTON -- NASA engineers are analyzing a small, but deep, gouge in the belly-mounted tiles on the space shuttle Endeavour to determine whether astronauts will have to repair the damage in a spacewalk, mission managers said Sunday.

The gouge, which Endeavour astronauts scrutinized earlier today with a laser-tipped inspection boom, runs all the way through a 1.12-inch (2.8-centimeter) thick tile on the shuttle's undercarriage exposing a small bit of felt filler material underneath, John Shannon, NASA's deputy shuttle program manager, in a briefing here at the Johnson Space Center (JSC).

"I don't have an idea of whether a repair will be required," said Shannon, who chairs Endeavour's mission management team. "But if we do, we'll address that and I have full confidence that if one is required, we'll go execute it."

Shannon said analysts have refined their estimates of the fuel tank foam debris that carved the gouge into Endeavour's underbelly 58 seconds after the orbiter's Aug. 8 launch.

It was a baseball-sized chunk of foam, slightly smaller than earlier, grapefruit-sized estimates, that fell from a bracket on Endeavour's fuel tank, then ricocheted off a metal strut into the tiles about four feet (1.2 meters) from the spacecraft's right landing gear door. After the initial hit, the foam scraped along Endeavour's aft leaving several secondary dings that were later found to be of no concern, NASA said.

"The primary concern is on the main gouge there that goes all through the thickness of the tile," Shannon said.

Deep damage

The foam damage etched a 3 1/2-inch by 2-inch (9-centimeter by 5-centimeter) gash across two tiles on Endeavour's belly. The damage left a tiny area of about 0.2-inch by 1-inch (0.5-centimeter by 2.5-centimeter) bare of any heat-resistant tile material, Shannon said.

In a bit of luck, the damage occurred right underneath a spot on Endeavour's wing that includes a metal rib, which also lends additional heat resistance to the local area, he added.

NASA has kept a watchful eye on shuttle fuel tank foam debris and the integrity of its orbiters' heat shields since the 2003 Columbia accident. A 1.67-pound (0.75-kilogram) chunk of foam breached Columbia's left wing during launch, leading to the loss of the orbiter and its seven-astronaut crew during reentry.

Since then, NASA has redesigned shuttle fuel tanks to minimize foam debris and instituted mandatory in-flight heat shield inspections for orbiter crews.

Shannon said engineers will use the detailed images and laser data collected on the gouge during Sunday's focused inspection to build a three-dimensional model of the damaged tile.

They will then run it through computer simulations Monday to study its thermal properties. Physical mockups of the damage will be also be tested in NASA's arcjet facility here at JSC, where they will be subjected the same extreme temperatures Endeavour will experience during reentry and landing.

Teacher-turned-astronaut Barbara Morgan, who originally served as NASA's Teacher in Space for Christa McAuliffe before the 1986 Challenger accident, helped survey the gouge in Endeavour's underbelly with the shuttle's inspection boom Sunday with shuttle crewmate Tracy Caldwell.

Extended mission

While engineers analyze Endeavour's tile damage, mission managers also decided Sunday to extend the shuttle's construction flight to the International Space Station (ISS) by three extra days.

The extension is due to the success of a new Station-to-Shuttle Power Transfer System that allows Endeavour to siphon electricity from the space station's solar power grid to conserve its own fuel cell-driven resources.

The Boeing-built system was activated just after Endeavour docked at the ISS on Friday and has been feeding the shuttle an average of six kilowatts, except during spacewalks when the available power was a bit lower.

"It's still behaving just perfectly," Matt Abbott, NASA's STS-118 mission lead shuttle flight director, said of the new system.

Initially slated for an 11-day spaceflight, Endeavour's STS-118 crew will now remain in orbit for about 14 days, 10 of them aboard the ISS for a record shuttle visit, NASA has said.

The extra time will allow Endeavour's crew to perform an extra, fourth spacewalk and should allow Morgan to take part in up to three interactive video events with students on Earth, NASA has said.

frigidmagi wrote:You know... At this rate we would save money by just biting the bullet and replacing the Shuttle.

Not to mention, you know, lives.

Shuttle Endeavour undocks from station

Updated Sun. Aug. 19 2007 8:26 AM ET

Associated Press

HOUSTON -- Space shuttle Endeavour undocked from the international space station a day early on Sunday, as NASA kept a wary eye on Hurricane Dean.

Space agency managers worried that the storm would move toward Houston and force them to evacuate to a smaller-staffed makeshift control center at Cape Canaveral, Fla. The Endeavour crew prepared to land on Tuesday as a precaution.

"Endeavour departed," space station commander Fyodor Yurchikhin said as ringing bells heralded the shuttle's parting, a tradition borrowed from the Navy.

"Thanks for everything, Scott and Endeavour crew," station resident Clay Anderson said to shuttle commander Scott Kelly. "Godspeed."

"We couldn't have gotten everything accomplished without you guys," Kelly replied. "We look forward to seeing you back on planet Earth."

The shuttle crew, which includes teacher-astronaut Barbara Morgan, had been at the orbiting outpost since Aug. 10. In that time, they attached a new truss segment to the station, delivered cargo and replaced a failed gyroscope, which controls the station's orientation.

They have had to compress their schedule to get ready for the early undocking. Morgan, who was Christa McAuliffe's backup on the tragic 1986 Challenger mission, was scheduled to talk to students in Massachusetts on Sunday but that chat was canceled.

A spacewalk on Saturday was shortened so the astronauts could wrap up their work at the station. During that jaunt, the spacewalkers saw the eye of the enormous hurricane swirling in the Caribbean and expressed their amazement at the sight.

The astronauts also skipped flying around the station after undocking to take pictures of the complex, an exercise NASA likes crews to do if the schedule and fuel supply permit.

Although it was uncertain whether Dean, a Category 4 storm, might strike the Texas coastline later this week, NASA managers said it would be irresponsible not to cut the mission short, especially since most of the tasks had been completed.

"I would defy just about anybody to tell me at this point that there's zero or even extremely low probability or possibility that the storm is going to come here," said LeRoy Cain.

NASA is ready to rush a skeleton crew of flight controllers to Cape Canaveral, but only if the shuttle cannot land Tuesday for some reason and the hurricane is bearing down on Houston and threatening the city for several days, Cain said.

"That's a fairly, I hope, unlikely scenario simply because all those things have to line up," he said.

In 26 years of space shuttle flight, NASA never has had to call up an emergency Mission Control, although it has been practiced.

NASA's hurricane deliberations followed a decision to forgo shuttle repairs.

Mission managers concluded earlier this week that a deep gouge on Endeavour's belly posed no Columbia-like threat to the seven crew members during re-entry and also would not lead to lengthy postflight shuttle repairs.

For several days, managers had considered sending two astronauts out with black protective paint and untested goo to patch the 3 1/2-inch-long, 2-inch-wide gouge that dug all the way through the thermal tiles.

The gouge was caused by debris that broke off a bracket on Endeavour's external fuel tank during liftoff Aug. 8. Engineers still do not know whether it was foam insulation, ice or a combination of both. In any case, NASA said it will not launch another shuttle until the longtime troublesome brackets are fixed.

Space shuttle Endeavour lands safely

Updated Tue. Aug. 21 2007 2:03 PM ET

CTV.ca News Staff

Astronauts aboard the space shuttle Endeavour are now safely back on Earth after a picture-perfect landing at the Kennedy Space Center Tuesday afternoon.

The six-member crew aboard the shuttle landed right on time at 12:32 p.m.

"Congratulations. Welcome home. You've given a new meaning to higher education,'' Mission Control told the crew, which included Barbara Morgan, a teacher-turned-astronaut and Canadian astronaut David Williams.

At one point, the shuttle faced intense 1,000-degree temperatures as it re-entered the atmosphere. Despite a gash on Endeavour's belly, there was little concern the heat would have a negative impact on the landing. Engineers conducted thorough thermal tests all week and were convinced the shuttle could withstand the damage.

Earlier, NASA officials feared Hurricane Dean would pose a problem with the shuttle's landing. But they later realized the storm would not affect Mission Control in Houston as had been predicted.

The spacecraft came in at an altitude too high to feel the effects of Dean, according to NASA officials.

Since preparations for an early landing had already been made, it was decided to bring the crew home early anyway.

"Since pretty much all of the mission's critical objectives had been completed by then, there was no reason to leave Endeavour attached to the space station any longer," said Mathieu Caron, mission controller with the Canadian Space Agency, speaking with CTV's Canada AM Tuesday.

The crew is expected to meet with the media at a press conference six hours after landing, after they undergo physical examinations and meet with their families, said a statement released by NASA.

NASA managers looked at several different ways of getting the crew home should they have run into weather problems, including transferring flight controllers to the Kennedy Space Center.

Landing was expected to go smoothly without a hitch despite a tiny window crack and an unrepaired gouge in Endeavour's belly. The shuttle underwent several days of analysis before it was decided the damage caused little risk.

This journey marked many accomplishments for the Endeavour crew. Williams set a record for the most spacewalks by a Canadian. There were also classes held on board the shuttle by Barbara Morgan, the first teacher to ever train as a full-fledged astronaut. She answered questions from space to students in Canada and the U.S.

The astronauts delivered 2,270 kilograms of cargo to the space station during the mission. They also replaced a gyroscope, to help steer the station's orientation, and attached a new truss segment to the outpost.

Canadian astronaut Dave Williams and his team of six other crew members awoke early Tuesday to the music of Simon and Garfunkel's "Homeward Bound. It was a tribute sent by their families.

"That's very nice of them to think of that,'' commander Scott Kelly told Mission Control. "Although it's been a short two weeks, we've accomplished a lot and we still look very much forward to coming home today.''