Debris-hit finding is disputed

Washington Post Via MSNBC ^ | Feb. 8 | Rick Weiss

[tophat9000]

Feb. 8 — The conclusion by NASA engineers that Columbia probably did not suffer serious damage from debris during its Jan. 16 launch was based on two key assumptions that no one could confirm as true, according to details in a pair of reports produced for NASA by Boeing Co. engineers during the flight.

THE TWO ASSUMPTIONS — that the shuttle was hit by a piece of and not by ice, and that the leading edge of the wing was not damaged by the impact — remain unproved. Indeed, NASA has explicitly acknowledged that ice damage has not been ruled out and, according to one of the Boeing reports, there was “large uncertainty” as to where the debris hit the spacecraft.

[tophat9000]

It looks like they are starting to consider there was an ice impact along with the insulating foam

[fooman]

U huh

[LibKill]

Ice, sure. But the 'foam' wasn't Barbasol. The insulating foam is said to be very hard, sort of concrete lite.

[fnord]

so they have not elimnated this possibility in their investigation ... and someone thinks this is damning news!?

[Chi-townChief]

This will be quite a challenge for NASA - ice and launch debris have been a hallmark of blastoffs since the Vanguard days. The differnce, of course, is that, in the old days, the orbiter sat atop the rockets whereas the shuttle essentially rides a bomb between two Roman candles. I have heard interviews with shuttle astronauts over the years who have commented on how they've been nailed with "everything but the kitchen sink" as the ascended through the atmosphere.

[fooman]

One report, for example, acknowledges that as engineers tried to predict the effects of a 1,200-cubic-inch to 1,920-cubic-inch piece of foam hitting the shuttle, they had to rely on data relating to an impact with a 3-cubic-inch piece of foam — a degree of extrapolation so extreme as to make prediction very difficult.

“Oh my gosh,” one aeronautical engineer said yesterday when shown that element of the report. “You have to be very cautious when you’re extrapolating that much.”

[fooman]

test

[DoughtyOne]

With regards to the assumption ice may have been involved, Dittemore stated that ice was an important issue for NASA, and that the main booster was checked shortly before launch for ice. He said they are fairly confident ice wasn't involved. (Seriously)

On a related issue, he stated that a 20" x 16" x 6" piece of insulation hitting the shuttle wing at 256 mph was studied and dismissed as a potential problem for the shuttle. (Seriously)

I guess you'll have to select which instances to agree with him.

[spunkets]

" The insulating foam is said to be very hard, sort of concrete lite."

Celotex with a tougher skin than paper.

[IronJack]

The volume of the insulation doesn't matter nearly as much as its mass. I recall reading somewhere that the chunk of foam that hit the wing would have weighed somewhere near 2 pounds. I'm no expert, but I have to imagine that the orbiter's leading edge could sustain a blow from a 2-pound object without said event threatening the craft, the crew, and the mission.

I've never bought the insulation damage theory.

Ice, on the other hand, could be fairly damaging, I would think.

[fooman]

‘TRYING TO FOOL THEMSELVES’

“This looks like a case of people trying to fool themselves into not being worried,”

said a former shuttle engineer who spoke on condition of anonymity yesterday after looking at the report.

Had the debris that hit the wing 80 seconds into flight been not foam but ice, one of the Boeing reports indicates, it could easily have breached the structural integrity of the wing — even the super hard reinforced carbon-carbon material used in the shuttle’s most heat-exposed areas.

That would leave the wing unprotected from the nearly 3,000-degree Fahrenheit temperatures reached during reentry.

And even if the debris were a piece of foam, it might have inflicted serious damage and undermined flight safety if the impact were just a few inches further forward than the engineers assumed, said two independent engineers and a former NASA flight controller who looked at the reports for The Post

[latrans]

Now is a good time for me to float my theory: That the foam impact densly packed foam into the small gaps between the tiles (for expansion). If the expansion gaps were jammed, with burned foam, the tiles might have a tendancy to pop off. I like my theory better than the space turd impact theory I heard today.

[MonroeDNA]

Let's not forget that the insulation was held on by an "environmentaly friendly" glue, which was weaker than the original. NASA switched glues, to be PC.

The current glue is NOT the strongest stuff available. They weakened it by going PC. Inexcusable.

Thanks, Clinton.

[the_doc]

The scenario may be worse than a matter of "PC" (or better, depending on one's viewpoint). NASA's insulation contractor may have switched to the envirnomentally friendly propellant as a matter of regulatory law, not mere PC.

[SteveH]

I tried calculating energy here:

http://www.freerepublic.com/focus/news/836736/posts?page=301#301

Trying again, using 730 fps instead of 200 fps,
energy (in MKS units) is

J = 1/2 * m * v ** 2

m = 2.6 lbs = 1.2 kg (approx)

v = 730 f/s = 223 m/s

J = 1/2 * 1.2 * (223 ** 2) j

= 29837 j

Applying fudge factor (hardness ratio ~10:1):

J of tile = 1/11 * J

= 1/11 * 29837 j

= 2712 j

Using a formula to get ane earth gravity drop height for a 1 kg mass

E = mgh

g = 9.8 m/s**2 (MKS)

2712 = 1 * 9.8 * h

h = 2712 / 9.8 m

= ~277 m

so it seems possibly equivalent to dropping a 1 kg mass 277 meters.

This seems like a large amount of energy... hmmm...

[Jael]

Keep bumping me. :-) I've been busy this weekend and haven't had much of a chance to comment. But I would appreciate any bumps so I can keep abreast of things. Thanks for thinking of me!