Director of NASA hopes for quick return to flight

Atlantis to launch in Sept., only if debris shedding solved

Shuttle Safely Back On Earth

August 10, 2005|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

With Discovery safely back on Earth, NASA's engineers will turn their full attention to figuring out why a menacing hunk of foam insulation broke away from the shuttle's external fuel tank despite 2 1/2 years of work to fix the problem -- the same one that doomed the shuttle Columbia.

NASA Administrator Michael D. Griffin, who has grounded the shuttle fleet until the problem is solved, says he hopes engineers can fix it without postponing the planned launch of the shuttle Atlantis, now six weeks away.

"I think we are going to fix it in short order, and we are going to get back flying," he said late last week. "We don't expect this to be a long, drawn-out affair, to be honest with you."

If Atlantis does miss the September launch window for reaching the International Space Station, the next one opens in November. Griffin said the space agency can still meet one of those windows "by being smart and working hard." While the delay might stretch into next year, he said, "We don't start out by assuming that we can't succeed."

But John Logsdon, director of the Space Policy Institute at George Washington University, discounted that optimism as "rallying the troops."

No one can say how long the delay might be until engineers begin to report on their findings, perhaps later this week, he said.

While engineers wrestled with the foam problem, shuttle Commander Eileen Collins flew Discovery to an on-time landing at 8:11 a.m. EDT, yesterday. The 14-day mission ended at Edwards Air Force Base in California after poor weather in Florida forced NASA to delay and finally cancel landing attempts there Monday and yesterday.

NASA quickly prepared the shuttle for the ride back to Florida atop a modified Boeing 747.

In orbit, Discovery's seven-member crew resupplied, repaired and replaced hardware on the station, whose operations had been curtailed by the grounding of the shuttle fleet.

Two spacewalking astronauts also successfully tested technologies for repairing the shuttle's thermal tiles and panels in case of damage during launch.

And, in an unprecedented and unrehearsed final spacewalk, astronauts Stephen Robinson and Soichi Noguchi plucked dangling cloth "gap fillers" from between thermal tiles under Discovery's nose, eliminating a potential re-entry hazard.

NASA plans to fly its three remaining shuttles until 2010 in order to complete the space station. By 2014, the work will begin to shift operations to an as-yet-undesigned Crew Exploration Vehicle, along with a mix of unmanned spacecraft.

Griffin has rejected as "overreaction" the view of critics that the shuttle is a white elephant that should be retired early.

Despite at least three foam failures on Discovery that exceeded pre-flight limits, he insisted that the mission as a whole was remarkably clean.

Detailed in-flight surveys revealed only about 25 "dings" in the spacecraft's heat shield surfaces, one-sixth as many as the previous average of 145 per flight.

"In the world of engineering," he said, "we did pretty well."

Although he has led NASA for less than four months, Griffin took responsibility for failing to solve the foam problem. But he added, "All we can do at this point is move forward."

At his direction, the space agency has formed several engineering teams to investigate the insulation problem, with help from the tanks' builder, Lockheed Martin. They will report to space station program manager Bill Gerstenmaier, who was to get his first briefing yesterday.

A news conference to discuss their progress could come as early as tomorrow.

Thanks to increased surveillance, engineers have far more data about foam shedding from Discovery than they had from the incident that punctured Columbia's left wing during launch. That damage led to the loss of the shuttle and its crew during re-entry on Feb. 1, 2003.

Because of the Columbia disaster, more than 100 cameras documented Discovery's July 26 liftoff. One of them captured video of the largest slab of insulating foam as it peeled off the tank and blew away. It didn't hit the shuttle, and experts said it was moving too slowly to do serious damage even if it had.

Gerstenmaier told reporters on Friday that engineers now have "a tremendous chance to learn from this exercise."

The insulation on the 153-foot tanks helps keep the craft's 526,000 gallons of super-cooled liquid hydrogen and oxygen fuel from warming up and expanding in the Florida sunshine. But the foam must withstand enormous physical forces.

Gerstenmaier said tank surface temperatures rise sharply as the super-cold fuel is used up, while outside temperatures plummet as the shuttle climbs toward space.

The exhaust plumes of the shuttle's solid fuel boosters scorch the foam. A shock wave created by supersonic winds batters it as the shuttle accelerates. Temperatures on the launch pad vary by season, and wind conditions aloft vary daily, so no two flights are identical.

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