Gouge Found on Shuttle Endeavour's Underside

SonicSpike writes " NASA has discovered a chunk missing from the underside of the space shuttle Endeavour. It was discovered after the shuttle docked with the ISS earlier today. Technicians theorize it may have been caused by ice ripping free of a fuel take during takeoff. From the article:'The gouge — about 3 inches square — was spotted in zoom-in photography taken by the space station crew shortly before Endeavour delivered teacher-astronaut Barbara Morgan and her six crewmates to the orbiting outpost ... On Sunday, the astronauts will inspect the area, using Endeavour's 100-foot robot arm and extension beam. Lasers on the end of the beam will gauge the exact size and depth of the gouge, Shannon said, and then engineering analyses will determine whether the damage is severe enough to warrant repairs. Radar images show a white spray or streak coming off Endeavour 58 seconds after liftoff. Engineers theorize that if the debris was ice, it pierced the tile and then broke up, scraping the area downwind. Pictures from Friday's photo inspection show downwind scrapes."

Comments

Can't be the First Time

[CWRUisTakingMyMoney]

I wonder how many times this kind of thing happened in the 20-ish years before the Space Shuttle started monitoring its underside like this. Surely this can't be the first time (ignoring Columbia) falling foam has taken a chunk out of the shuttle's heat shielding. IMHO, this is a nearly inevitable side effect of the idiotic design of the shuttle, putting the astronauts next to the fuel and not above it. These kinds of tests and precautions can only be good, but if NASA had stuck with what worked up to that point (astronauts on top of the assembly) instead of changing things up, the tests and worries wouldn't be necessary, and lives would have been saved in 2003, and possibly 1986. Here's hoping this turns out to be inconsequentially small, or at least easily repairable.

Re:Can't be the First Time

[AKAImBatman]

I'm sure it did, but there were several other issues as detailed in this Space.com article:

Foam coming off the tank because of improper application; deficiencies in the materials used; degradation during its transport to the Cape; the loading of supercold fuels; and the violent ride to space. Florida Today reported earlier this year that foam came off the tank on at least 71 flights to date, but NASA did not consider the resulting damage to the heat shield a safety issue.

Requirements and specifications not being followed in testing and manufacturing of the external tank.

Loss of institutional knowledge and experience at NASA and the Michoud plant because of "lots of old-timers retiring or taking buyouts" as the shuttle program reduced its workforce throughout the latter half of the 1990s.

NASA's limited insight into changes vendors had made with materials used in making the tanks.

Environmental requirements requiring removal of freon from the process for spraying the foam insulation onto the tank. NASA has said that the freon-free application method resulted in foam that initially did not adhere to the tank as well, but changes were later made to strengthen the bond of the environmentally friendly foam.

On top of all that, the shuttles themselves are just getting *old*. I imagine that leads to all sorts of maintenance and structural issues. They may still be within engineering tolerances, but engineering tolerances for the Shuttle predicted a 1 in 100,000 flight failure. A figure which Richard Feynman challenged and reduced to somewhere between 1 in 50 and 1 in 100.

So far we're on target for Dr. Feynman's predictions. :-/

Re:Can't be the First Time

[florescent_beige]

I wonder how many times this kind of thing happened...

Lots (yes it's a pdf so kill me). See page 9.

Sorta reminds me of the time the de Havilland Comet blew up in mid air and aviation engineers learned about fatigue and decided to go look at other airplanes for signs of fatigue cracks and found them everywhere. Talk about freaking out.

Then, after that, several smart people[1] figured out that cracks always had been everywhere and, you know, chill. The airplanes we fly around on have lots of cracks. The thing that saves our collective butts is that they are understood.

1 P Paris and F Erdogan (1963), A critical analysis of crack propagation laws, Journal of Basic Engineering, Transactions of the American Society of Mechanical Engineers, December 1963, pp.528-534.

Re:Can't be the First Time

[Dunbal]

Not only that, but they insist on rolling the shuttle over to fly upside down underneath the main engines which increases the likelihood of debris from the main engines hitting the payload.

      Not at that speed. Gravity becomes negligible when creating vectors compared to the wind resistance. Upside down, vertical, horizontal, it doesn't matter. There's only one real direction: DOWNWIND. That's the only place your debris is going to go.

      Now you could make the argument that some of the streams of air are shaped to blow debris onto the shuttle, that I would buy. Gravity has nothing to do with it, however.

Re:Can't be the First Time

[vought]

The shuttle has become a death trap because NASA has placed image before technological reality.


Oh, bullshit.

The shuttle may have been a flawed design to begin with, and that may have been because NASA was concerned with big-budget DoD and pie-in-the-sky programs during the 70s...but practically everything except the shape of the ship has changed since the Shuttle first flew in 1981.

It hasn't "become" a death trap. Even LEO flight is risky, and the Shuttle is heavy and uses very bleeding-edge technology (still) like throttled H2/LO2 engines. Be honest and argue about the fundamentals of the Shuttle designs, but don't try to bullshit me and claim that things have gotten more dangerous for Shuttle crews now.

Maybe they should have started Constellation ten years ago - but on the whole, the Shuttle is safer now than it has ever been; in other words, still very dangerous, but less so than before Columbia.

I apologize for the brusque tone, but it really cheeses me off when people who do nothing but read NASAWatch.com think they know how complex and difficult manned spaceflight really is - especially with 35-year-old technology.

Where's the 250 Foot Robot?

[florescent_beige]

...using Endeavour's 100-foot robot arm and extension beam. Lasers on the end of the beam...

You know what bugs me? Ok? They have this 100-foot robot arm but they don't have the 250-foot robot that it must have come from. I mean if it has lasers on its ARM, imagine what else it has lasers on. Like, for example, on it's frikken head.

Which it's important to know if theres a 250-foot frikken robot with frikken lasers on its frikken head out there roaming around all mad because NASA ripped its arm off.

Re:Where's the 250 Foot Robot?

[jollyreaper]

You know what bugs me? Ok? They have this 100-foot robot arm but they don't have the 250-foot robot that it must have come from. I mean if it has lasers on its ARM, imagine what else it has lasers on. Like, for example, on it's frikken head. Yeah, you'd think having a 250-foot tall robot would be cool but the damn thing needs an extension cord and the battery only works for five minutes.

Re:First post

[Tablizer]

3 years of reloading slashdot every day finally comes to fruition.

Think that's hard, next try to get your First Girlfriend :-)

More reading

[Anonymous Coward]

Here's a non-sensationalist summary of the situation that's not just yanked from AP:

http://www.nasaspaceflight.com/content/?cid=5195

The damage is likely minor, but the media loves jumping on these things.

Re:It's curtains for them

[Anonymous Coward]

Actually it depends a lot on the shape and mass of the piece of debris. When the piece of debris separates from the fuel tank it has the same velocity as the shuttle. Then it interacts with the atmosphere. For a piece of foam, it will slow down extremely rapidly in the lower atmosphere so that there is a large difference in velocity when the Shuttle rams it. In the upper atmosphere which is much more diffuse the difference in velocity will be much slower. For a piece of ice which will have a high mass and possibly a streamlined shape, it would not slow down nearly as much as a piece of foam. But the ice might have a greater mass. Depending upon the situation the kinetic energy (1/2*mv^2) may be higher for the foam due to the square of the velocity term.

For these reasons a loss of foam in the upper atmosphere when the Shuttle is traveling Mach 15 (for example) is not as serious as a loss of foam in the lower atmosphere when the Shuttle is traveling Mach 1. The point of maximum damage for a piece of foam or ice will occur when the slowing down of the debris relative to the speed of the shuttle is at a maximum. The piece that doomed Columbia broke off when Columbia was traveling roughly 1700 mph at about 80,000 ft. It was estimated that the piece struck with a difference in velocity of about 530 mph. This is relatively close to Max Q. Any impact within about 30 seconds of Max Q is very dangerous.

The shuttle can land without pilots

[Mal Reynolds]

The Discovery was given remote landing capability in 2006. I would be shocked if the Endeavour didn't have this same capability.

http://science.slashdot.org/article.pl?sid=06/06/3 0/0458246&from=rss

If mission control thinks a manned landing too risky, they'll just hook up the remote system and send down the can without the spam. Another Shuttle will be sent up in 6 or 8 weeks and take the whole lot of them home.

This would probably be another large setback to the ISS and to the astronaut corps. The "rescue mission" would probably depart with just 2 or 3 astronauts. And if the Endeavour was lost on re-entry, it would probably doom the shuttle program.

Sucks to be an astronaut these days. Chances of dying, 1 in 59, and you're lucky to get a single ride every 10 years.

On the other hand, SpaceX may get be getting some rush orders for Falcon 9's and Dragons.

Re:Perseid meteor shower

[imemyself]

I've read that a little piece of paint made a fairly noticeable "dent" in the Shuttle's windshield. Here's a website that mentions it: http://www.spacetoday.org/Satellites/SatBytes/Spac eJunk.html

Several other sites showed up on Google when I searched for shuttle, fleck of paint, windshield

Considering how small the mass of the paint must have been, I could easily see how a small pebble sized object could cause major damage, but I'm not a rocket scientist. I think there has also been some general concern about all of the debris from China's ASAT test earlier this year. I think they are tracking most of the thousands of pieces of debris, so they would hopefully have an idea if something was coming, but I'm sure that they can't track the smallest pieces of debris. There are some animations on the web that show how the debris spread out from that test - its really amazing.

When you're traveling at 7 km per second, hitting anything that is not traveling along with you on a similar orbit (they would have similar velocities and wouldn't be moving as fast relative to you) has got to be seriously bad news.

Re:Perseid meteor shower

[florescent_beige]

Lucky for you my young padawan I have no life.

Does anyone know how/if NASA handles things like micrometeorites?

Dunno exactly, how's that for a start? I do know the shuttle's glazings are replaced about once every 10 flights due to impact, mostly with man made stuff like paint chips from exploded satellites. Just guessing here and don't quote me, but the way they deal with this is probably with stats. As in, if a chip of paint can ding a window, I guess a gram-sized piece of debris can poke two holes in the orbiter (an in and an out). Although, that might not be fatal if it doesn't pass through someone's body, the little hole can probably be patched with, you know, the space shuttle hole patch kit they must have.

The Orbiter is maneuvered to avoid known space debris, but that only goes down to about tens of centimeters. So stuff smaller than that has to be handled with stats.