AP Photo
Posted on 06/04/2003 6:55:02 PM PDT by NormsRevenge
By MARCIA DUNN, AP Aerospace Writer
CAPE CANAVERAL, Fla. -
The Columbia accident investigator in charge of a series of impact tests said Wednesday he is surprised by the incredible force with which a 1 1/2-pound chunk of space shuttle foam struck and deformed a fiberglass wing replica.
NASA (news - web sites)'s Scott Hubbard said he expects even more damage when real shuttle wing parts — weaker and more brittle than fiberglass — are used for the next round of testing, beginning Thursday. He expects the actual pieces, removed from shuttle Discovery, to actually break.
"This moves us a lot closer to saying that the foam can do this kind of damage," said Hubbard, a member of the Columbia Accident Investigation Board.
The board suspects a similarly sized piece of fuel-tank foam insulation knocked the hole in the leading edge of Columbia's left wing that, two weeks later, let in scorching atmospheric gases and doomed the spaceship and its seven astronauts during re-entry.
In last week's test at the Southwest Research Institute in San Antonio, a piece of foam nearly 20 inches long was fired through a giant nitrogen-pressurized gun at more than 530 mph at a mock-up of the wing's leading edge. The fiberglass panels and seals were from the shuttle prototype Enterprise (news - web sites), which never flew in space.
The foam deflected the panel that was the bull's-eye and shoved and lifted an adjoining seal, Hubbard said. The foam shattered, and pieces of it crammed into the nearly half-inch gap created by the dislodged seal. The crevice — about 22 inches long — held its shape because of the foam stuffing.
"People's intuitive sense of physics is sometimes way off. You don't feel that this (foam) can do anything," Hubbard said. "But you fire this at 500 mph and there you saw it. I really did think,`Oh, my God, this is really an impact. This is a significant effect.' ... That's when it came home to me, what it really means."
The stress recorded in the May 29 test was up to seven times higher than expected and rippled across the panels, Hubbard said. But that peak force lasted just one-half of one-thousandth of a second, not long enough to break fiberglass, he noted.
It equated to a ton of force, all compressed into 60 or 70 square inches of fiberglass panels, Hubbard said. According to predictions, that is perhaps 70 percent more force than needed to break real leading edge pieces, which are made of reinforced carbon.
At Kennedy Space Center (news - web sites), meanwhile, the chairman of the Columbia reconstruction team gave a final news media tour of the 85,000 pounds of wreckage.
Mike Leinbach, who normally works as launch director, said the debris points to the breach as having occurred probably somewhere around the bottom of carbon panel No. 8 of the left wing's leading edge. The initial hole could have been in the panel itself or an adjoining seal; there is not enough evidence to know for sure, he said.
"The key here is how much is not here, versus how much is over on the right-hand side," Leinbach said, pointing to what little is left of the left wing. "Columbia held in there. She hung in there for a long, long time," he said, gazing at the scorched fragments on the hangar floor. "She tried to fly. She tried to come home."
Columbia was 16 minutes away from Cape Canaveral, Fla., when it shattered over Texas.
___
On the Net:
Columbia Accident Investigation Board: www.caib.us
Nice engineer they have in charge. There have been cases where objects in a car that are not even a 1/2 lb have killed occupants in 35 mph crashes. One was a tissue box that was 1/2 full which flew from the rear window and hit the driver in the back of the head/kneck and killed the driver. That was a 45 mph accident.
The Columbia accident investigator in charge of a series of impact tests said Wednesday he is surprised by the incredible force with which a 1 1/2-pound chunk of space shuttle foam struck and deformed a fiberglass wing replica.Imagine the damage a 1 1/2-pound chunk of cheese could cause a a fiberglass wing replica. I'm thinking colby or a port wine cheddar. But even a bri wheel or camembert could cause some real damage.
My 2/18/03 kinetic energy estimate is here. One way or another, a big jolt...
All of us morons, that make up the great unwashed, can't possibly make a correct assessment by simply viewing some video we saw on CNN or Fox.
Why, we're not paid millions of dollars to make those types of judgements and pronouncements. That is a skill that takes years of study and sucking at the Government teet to cultivate. Harumph, harumph.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.