NASA Studies Debris Recorded During Launch

[tocqueville]

16 minutes ago

CAPE CANAVERAL, Fla. - In uneasy reminders of the Columbia accident, a thermal tile apparently got chipped and other debris whirled around Discovery as it rumbled toward space Tuesday, but it wasn't clear if the shuttle's sensitive skin had been jeopardized.

A 1 1/2-inch-wide bit of tile captured on camera appeared to fly off the shuttle's belly, on the edge of a door that encloses the nose landing gear. It was not clear if the tile had been struck by anything. Pieces of tile, which protect the shuttle from searing heat on return to Earth, have been lost on past flights without preventing a safe homecoming.

"We're going frame-by-frame through the imagery," said John Shannon, a NASA operations manager.

http://news.yahoo.com/news?tmpl=story&cid=514&u=/ap/20050726/ap_on_sc/shuttle_debris_1

[Placebo]

1. Oy, not again.

Lets hope this piece isn't big enough to be dangerous.

[FogerRox]

2. tile by the nose gear--- oh jeese

[jsamuel]

6. Do they carry extra tiles?

just in case?

[punpirate]

3. And, pieces of tile lost...

... have caused the shuttle to burn up before a safe homecoming.

The really odd part of this is that very early on, the main tank was painted (white, I believe). After a couple of missions, it was decided to leave the tank unpainted because it would save ~1000 kg. Now, paint isn't that strong, but with the tank painted, the chances of pieces of foam from the main tank simply falling off from adhesive separation would be minimized, one would think. That would, in turn, minimize the chance of a hunk of foam from the main tank damaging tiles on the orbiter.

Guess the motto of NASA is "never look back."

[Johonny]

4. Why?

"the chances of pieces of foam from the main tank simply falling off from adhesive separation would be minimized, one would think."


I see no reasonable logic to this statement.

[FogerRox]

5. Liquid oxygen causes frost on the outside

The freezing is what helps the insulation come off, no layer of paint will help

[punpirate]

7. You don't?

Go out and paint a piece of urethane foam with a suitable urethane paint on the outside and then see if it will fall apart with the underside (away from the paint) frozen.

I think you'll find that the paint skin will hold the pieces together. The problem here is that the foam is applied directly to the metal skin of the main fuel tank. The main tanks are recovered and reused. Over time, with hot/cold cycling, the foam loosens in spots that aren't apparent by visual inspection. Upon ignition and launch, vibration causes those pieces of foam to break loose and fall off, and, sometimes, damage the tiles on the orbiter. That was the cause of the damage to the tiles on the Columbia which caused its failure upon re-entry.

Cheers.

[Johonny]

8. No they're not

The main tanks are not recovered and reused. The side boosters are recovered but while they were suppose to be reusable. They aren't reused. The binding would help some. But in the shuttle experienced foam hits even when the paint was on. The binder can't prevent the problem and it's unclear that it improves the safety.

[punpirate]

9. My error...

... you're correct. I thought both boosters and the main tank were recovered. Never mind. :)

[FogerRox]

10. really ---the main tank is released like umm

20 miles up.

[rumpel]

11. LATimes:

I was looking for the front page info of the print version, but they have now updated info.

http://www.latimes.com/news/science/la-072705shuttle_lat,0,1817854.story?coll=la-home-headlines

snip

After the Discovery launch Tuesday, NASA officials said there were three incidents involving possible debris from the craft, including what may be a 1 1/2-inch chip in a thermal tile near the nose's landing gear doors. The engineering community is continuing to study the situation, Hill said.

"Their judgment based on the data so far is that it is not going to be an issue," Hill said. They "continue to meet and review the data.

"The story remains the same" as on Tuesday, Hill said. Engineers "have not yet made a decision on whether they need more data. On first judgment, they have enough data to make a decision. The jury comes in on those decisions tomorrow."

snip

In addition to the question of the tile chip, NASA has shown video of an object spinning off from the external fuel tanks as they separated from Discovery. The shuttle was not hit.

Also during launch, Discovery killed a bird in the first few seconds.