"Discovery" encounters a problem similar to what doomed "Columbia" and its seven astronauts in the last mission, NASA acknowledges, as it suspends further space shuttle flights.
By CURTIS KRUEGER, Times Staff Writer
Published July 28, 2005
One day after celebrating a triumphant return to space, NASA grounded its space shuttle fleet indefinitely Wednesday because a chunk of foam fell during launch, in an episode eerily similar to one that ultimately destroyed the shuttle Columbia in 2003.
The falling foam appears to have missed Discovery during Tuesday's launch, so it should not endanger the seven astronauts who are orbiting Earth. But it's a tremendous blow to NASA, which has spent 2 1/2 years and $1-billion with one main goal in mind: Stop the foam from falling.
"You have to admit when you're wrong," said shuttle program manager Bill Parsons. "We were wrong. We need to do some work here, and so we're telling you right now that the . . . foam should not have come off. It came off. We've got to go do something about that."
The decision raises doubts about the future of the space shuttle program, which already was in its last years and on an ambitious schedule. On the other hand, it indicates NASA may be doing what outside investigators criticized it for not doing in 2003, putting safety concerns ahead of launch schedules.
The decision came on the same day that NASA was dealing with another concern, analyzing an an 1 1/2-inch-long section of thermal tile on Discovery's belly that might be chipped.
The heat-resistant tiles on the shuttle's underside and panels on its wings and nose protect it from the blistering 3,000-degree heat of re-entering Earth's atmosphere.
NASA, for the first time, created a rescue scenario for this flight, a last-ditch plan that would call for the shuttle Atlantis to rescue Discovery's crew in the case of serious damage to the ship. But now Atlantis is grounded, which leaves the status of a rescue option unclear, although NASA officials said Wednesday they considered the necessity for a rescue mission remote.
Foam covers much of the shuttle's giant orange external tank, and while it is light, that doesn't make it harmless. A falling laptop-sized piece gashed Columbia's left wing in 2003, which doomed the shuttle as it re-entered Earth's atmosphere.
Engineers say they believe Tuesday's piece of foam was 24 to 33 inches long, 10 to 14 inches wide, and between 2 and 8 inches thick, which makes it somewhat smaller than the chunk that smashed into Columbia.
Although the foam that fell Tuesday appears to have drifted away without hitting the main shuttle vehicle, called the orbiter, the chunk could have caused serious damage had it struck the spacecraft, NASA says.
"We think that would have been really bad, so it's not acceptable," said deputy space shuttle program manager Wayne Hale, explaining why it was necessary to study the problem further before allowing any future flights.
The timing of the foam breakaway might have made a major difference in the condition of the shuttle. The Columbia mishap occurred about 82 seconds into the flight, at a point where the atmosphere was still dense and helped propel the foam into the orbiter wing. The breakaway on Discovery occurred at the two-minute mark, in very thin atmosphere, allowing the foam piece to drift off harmlessly.
"It appears we're back at the same problem," said Howard McCurdy, a space policy expert at American University in Washington, D.C. "It may be endemic to the design of the shuttle, that's the scary part."
Left unclear is what this means for the space shuttle program, which already is in its final years. The Bush administration plans to mothball shuttles after 2010, and until then all flights will be at least partly devoted to completing and resupplying the international space station.
But that's an ambitious schedule for finishing the complex space station, with which Discovery's astronauts plan to meet up today. Grounding shuttles for any length of time will make it harder to finish that work.
In the meantime, NASA and its contractors will have to go back to the drawing board over foam. Foam covers the external tank, the half-million gallon, orange, torpedo-like container that carries fuel for the shuttle's three main engines.
Foam is important because of the rocket fuel stored inside. It's super-cold liquid hydrogen and liquid oxygen, which are minus-423 degrees and minus-298 degrees Fahrenheit, respectively. That's so cold that the outside of the tank would normally coat itself in ice, even in Florida's heat. Falling ice is heavy, and would endanger the shuttle even more.
"You take it and light a rocket motor underneath it and occasionally a piece (of foam) comes off," said Peter Erdman, a professor of physics at Embry-Riddle Aeronautical University. "The trouble is, when a piece comes off, that's not good."
The foam was designed as insulation to prevent the ice. In the 2 1/2 years since Columbia, NASA redesigned the external tank to make it safer. For example, it removed foam from a strut that holds the tank to the orbiter, because that's where the Columbia foam sheared away from. It was understood that smaller pieces of foam would continue to fall.
The events of Wednesday contrasted with the scene in NASA offices in 2003.
Back them, a handful of NASA engineers debated in private whether falling foam might have damaged Columbia, but the debate never reached NASA's highest levels.
It also never reached Columbia's crew.
Discovery's crew was informed on launch day that debris had fallen from the external tank. The crew, commanded by Eileen Collins, includes Stephen Robinson, Soichi Noguchi, Jim Kelly, Andrew Thomas, Wendy Lawrence and Charles Camarda.
On Wednesday, foam was a major focus even before NASA grounded the fleet. Discovery's astronauts used a new device to peek under the space shuttle in midorbit and a team of 200 people on the ground looked for any other damage.
Among the things NASA was investigating was the apparently damaged thermal tile. The mission's lead flight director, Paul Hill, said engineers' "first blush" assessment was that the chip wouldn't pose a problem.
He assured that NASA planned to continue to study it.
"We all know TPS (thermal protection system) damage cost the life of the last crew," Hill said.
In addition to the big chunk of foam, several smaller pieces broke off, including at least one from an area of the fuel tank that had been modified after Columbia.
The foam fell from a portion of the external tank called the protuberance air ramp, which was modified only slightly after the Columbia disaster.
NASA's announcement obscured some good news about Tuesday's launch. Despite placing 107 cameras on land, on jets and on the space shuttle itself, NASA has so far not seen serious damage like the hole in Columbia's left wing that led the spacecraft to disintegrate as it plunged through Earth's atmosphere, when temperatures can reach 3,000 degrees.
The astronauts also spent Wednesday looking for damage. In a first, the crew maneuvered a 100-foot arm mounted with lasers and a camera and checked for damage on Discovery's wings and nose.
In another first, commander Collins plans to fly Discovery in a backflip today, so astronauts aboard the international space station can photograph the belly to look further for damage. Then Discovery will dock with the space station, to bring it supplies, and a new gyroscope.
These new inspection methods are giving NASA officials a wealth of data. But each imperfection they find brings a question along with it: Is this serious damage, or just the sort of minor pockmarks that shuttle orbiters always encounter when re-entering the atmosphere? NASA said it was working to take each sign of damage seriously, without overreacting.
Taking the issue a step further, Robinson and Noguchi are planning a spacewalk on Saturday to test two repair methods on samples of the heat-resistant tiles and panels. The methods are not cleared for use on this flight, but it's possible they could one day be used by astronauts to fix damage on a future mission.
Times Staff Writer Curtis Krueger can be reached at krueger@sptimes.com or at 727 893-8232. Information from the Associated Press and the New York Times was used in this report.
