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The gouge on the shuttle Endeavour  (Source: NASA)
NASA officials have no easy decision when it comes to the gouge located on shuttle Endeavour

Even after discovering a 3-inch-by-3-inch gouge located on the underside of the space shuttle Endeavour, NASA believes it does not pose a safety risk to the shuttle's crew.  Officials are now conducting a number of simulations in an attempt to determine if the shuttle can make it back to Earth with no repairs.

Assuming NASA decides to fly the shuttle back to Earth in its current state -- without repairing the gouge -- it could worsen during the violent re-entry into Earth's atmosphere.  Although the shuttle should be able to safely land in Florida, Endeavour would need expensive, time-consuming repairs that may throw NASA's manned launches for 2007 out of sync.

However if NASA decides to attempt to fix the gouge while in space, it's possible the astronauts who conduct the spacewalk could instead further damage the volatile underside of the shuttle.  The current generation of space suit is a large 300-pound suit that is hard to maneuver in -- not to mention the 150 pounds of tools that the astronaut will have with him.

If a decision is made to attempt to repair the gouge, three potential methods can be utilized by spacewalking astronauts.  Heat-reflecting paint could be applied around the gouge, a metal plate can be installed to help create a makeshift cover for the gouge, or some type of thermal heat-resistant paste could be used to fill the gap.

The U.S. space agency will decide sometime tomorrow whether or not they will attempt to repair the gouge.

Until NASA officials on Earth decide what the astronauts aboard the ISS should do, business will likely continue as scheduled in space.  Spacewalks and general construction of the ISS will continue.

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Hmm
By JackBeQuick on 8/14/2007 4:32:11 PM , Rating: 2
Don't they replace the tiles after each launch anyway? How would that delay future launches?




RE: Hmm
By ajfink on 8/14/2007 4:58:41 PM , Rating: 1
I thought they did, but perhaps in the case of damaged tiles they examine the underlying structure in detail and that would push back the schedule. It seems to me that filling it up with thermal-resistant paste of some sort would be the most logical and simple route.


RE: Hmm
By gibbsk on 8/14/2007 5:05:03 PM , Rating: 3
I agree that using the "goo" would be likely the best option. The only concern with that if it were used to fill the entire gouge, then it would need to be smooth so as not to cause extra friction upon reentry.

If this is not addressed in some way, they will have to do a lot of repairs to the belly of the shuttle, which really would stink considering the extremely tight schedule they are running on.


RE: Hmm
By kkwst2 on 8/14/2007 5:12:22 PM , Rating: 5
Well don't tell us, call NASA. They're wasting their time with costly simulations when you've clearly deduced the correct solution with almost no data or information. Bravo.


RE: Hmm
By PrinceGaz on 8/14/2007 6:37:51 PM , Rating: 2
Hehe, that's superb. I don't know why you've been downrated, as that is sarcasm at its best. It made me giggle anyway.


RE: Hmm
By ryedizzel on 8/14/2007 6:52:03 PM , Rating: 1
quote:
Well don't tell us, call NASA. They're wasting their time with costly simulations when you've clearly deduced the correct solution with almost no data or information. Bravo.

LMAO


RE: Hmm
By devolutionist on 8/14/2007 8:09:55 PM , Rating: 1
quote:
Well don't tell us, call NASA. They're wasting their time with costly simulations when you've clearly deduced the correct solution with almost no data or information. Bravo.


pwned


RE: Hmm
By GrJohnso on 8/14/2007 4:59:01 PM , Rating: 2
The thought is that by not fixing it now somehow, it will get worse under the forces of reentry, causing additional damage beyond a few broken tiles... Those are heat shields.. If they don't do their job, things inside start to melt/warp/break...

The theory was that a more severe version of this is what caused the last shuttle to disintegrate on reentry... I'd put money on at least some kind of minor repair...

Space Bondo? ;)


RE: Hmm
By timmiser on 8/14/2007 5:12:58 PM , Rating: 2
quote:
The theory was that a more severe version of this is what caused the last shuttle to disintegrate on reentry...


I believe NASA came to the conclusion that the Columbia problem was actually a hole in the leading edge of the wing. I would think there is a big difference between a hole and a damage tile.


RE: Hmm
By Michael Hoffman on 8/14/2007 5:20:28 PM , Rating: 3
Regarding shuttle Columbia:

"The independent investigation team has all be arrived at a firm conclusion. A seal on the left wing was struck by foam during liftoff and fell off the next day, they believe, creating a gap that let hot gas enter the ship during re-entry."

Taken from Space.com - http://www.space.com/missionlaunches/sts107_caib_0...

NASA just wants to be as sure as possible that the shuttle will be able to land safely on Earth. Money shouldn't (and likely isn't) an issue here.


RE: Hmm
By Hakuryu on 8/14/2007 5:33:36 PM , Rating: 2
I read that same explanation, but I cannot fathom how a piece of foam could damage a shuttle.

You hear about airplanes being struck by lightning with minor damage and they land safely, yet a billion dollar shuttle can't withstand some foam.


RE: Hmm
By ebakke on 8/14/2007 6:05:14 PM , Rating: 2
You make it sound like someone chucked a 3M Scotch Pad at the thing and that's what caused the damage

I wish NASA would describe it as something other than foam, because the general public has a very different image in than the actual product.


RE: Hmm
By PlasmaBomb on 8/14/2007 6:05:25 PM , Rating: 2
The heat tiles are incredibly brittle and quite easy to damage (hence the concern with the astronauts breaking more). It was a rather heavy lump of ice too (several kilos travelling downward whilst the shuttle was accelerating upward so big rate of closure).


RE: Hmm
By timmiser on 8/14/2007 6:21:10 PM , Rating: 3
How about if I shoot "some foam" out of a cannon and coming at you at 1000 mph while you stand there and take it OK?

Hey, stop moving and hold still... why are you cowering like a little girl? It's just "some foam".


RE: Hmm
By SiliconAddict on 8/14/07, Rating: 0
RE: Hmm
By soydios on 8/15/2007 12:46:27 AM , Rating: 2
it comes off at the same velocity, but if it comes off early in the flight, the air decelerates it relative to the shuttle, so the delta-v at impact is greater, not to mention that the shuttle is also accelerating at about 2 gees.


RE: Hmm
By timmiser on 8/15/2007 1:55:39 AM , Rating: 2
Actually, my estimate of 1000 mph took into account this. As soon as the foam or ice detaches it violently starts to decelerate. Imagine throwing a pc of foam out your car window on the freeway. It stops its forward momentum in a matter of feet. The shuttle is moving over 17,000 MPH when it hits orbit so I think my foam hitting at 1000 MPH was more than a fair estimate.

(Other factors to a lesser extent that the air drag provides is that the foam is no longer being pushed upward by the thrust of the vehicle and gravity immediately starts pulling it down.)

By the way, the foam on the ET is definately NOT thick and heavy but once again we get back into that whole velocity issue.


RE: Hmm
By stromgald on 8/15/2007 8:03:37 PM , Rating: 2
I think most of the ice shakes off early from vibration and initial acceleration. The foam that comes off and damages the shuttle happens a lot later in the flight when they fire the pyros that hold the SRBs and main tank.


RE: Hmm
By Zurtex on 8/14/2007 8:08:59 PM , Rating: 2
It's not the same thing at all. It's also pretty easy to consider why a peice of foam can cause so much damage:

F = 1/2 * m * v^2 (Force equals half mass times velocity squared)

That is to say, 10 times the mass and you get 10 times the force,10 times the velocity and you get 100 times the force.


RE: Hmm
By nineball9 on 8/15/2007 12:05:25 AM , Rating: 2
I suspect you mean E = (1/2)MV^2. [Kinetic] energy, instead of force.


RE: Hmm
By devolutionist on 8/14/2007 8:13:54 PM , Rating: 5
http://spaceflightnow.com/shuttle/sts107/030707imp...

"The foam was fired at the wing mockup at roughly 775 feet per second, or about 530 mph, at an impact angle of 22 degrees. That's higher than the impact angle during Columbia's launch. But by adjusting the impact angle, engineers were able to account for rotational energy imparted by the tumbling foam. Hubbard said the impact imparted about a ton of force to the RCC panel. All of the test parameters, taken together, represented an "average" set of conditions. The actual impact could have been somewhat worse or somewhat less violent. But the hole that was blown in RCC 8 leaves little doubt the foam strike caused the breach responsible for Columbia's destruction."


RE: Hmm
By Ringold on 8/14/2007 5:17:41 PM , Rating: 2
quote:
Don't they replace the tiles after each launch anyway?


Not unless they're damaged. Those are really, really cool pieces of material..

quote:
How would that delay future launches?


It could do enough damage to not compromise the integrity of the airframe but enough to cost a fortune and be time consuming. Repair and maintenance work on aircraft is insanely expensive, and often time consuming, as it is. Trying it on the worlds most complex ship with government workers and I can imagine it would delay their schedule alright..

Honestly though, I'd rather see an astronaut at least try to do something about it. If there's any question at all that the integrity of Endeavor could be compromised on re-entry then I think they should try to patch it. Astronaut's are highly skilled, highly trained professionals in general despite how they appear in the media and should be trusted with the space-age equivalent of slapping duct tape on Endeavor's belly. It'd be a huge tragedy to lose another crew and another orbiter, especially when it's known in the public that the chance may be there this time.


RE: Hmm
By PlasmaBomb on 8/14/2007 6:11:22 PM , Rating: 3
quote:
Repair and maintenance work on aircraft is insanely expensive, and often time consuming, as it is.


Repair work on military jets is 10:1 - 10 hours maintenance for every hour of flight. The shuttle would be more labour intensive, without potentially damaging the air frame due to hot gasses entering through a pinhole (provided it makes it to the ground that is).


RE: Hmm
By Ringold on 8/15/2007 12:41:51 AM , Rating: 2
quote:
Repair work on military jets is 10:1 - 10 hours maintenance for every hour of flight.


That.. can't be right?

Out of curiosity, what is it that is so time consuming about military jets? Does the hot section of the engines have to be monkey'd with after each flight or something?

Even I'm a little stunned at that ratio, and I figured it was bad.


RE: Hmm
By NT78stonewobble on 8/15/2007 8:56:25 AM , Rating: 2
That is very correct AFAIK...

I think even 10 hours is a bit optimistic?

I can't remember it correctly but I think the F-14 was partly retired because it had about 30 hours of maintenance compaired to every 1 hour of flight.

That is compaired to it's successor the F/A-18 (or what ever the super hornet is called). Which was sposed to have less than 20 hours of maintenance per flight hour.

I think the marines A/V 8 (harrier jet) has the same problems.

Well don't take my numbers as factually correct but it is a very maintenance job to fix fighters / bombers...

PS. Have a danish airforce f-16 mechanic in the family. Damn good at that job but can't fix a tumbler for the love of god... lol


RE: Hmm
By iNGEN on 8/15/2007 12:59:51 PM , Rating: 2
Ringold,

Don't forget there can be major problems caused by the solution, whichever is chosen. I think the point of the comments about the unwieldiness of the spacesuit and tools is to convey the level of precision involved in the heat shield tile system. Most of the repair/assembly work done in space is prepared on earth in incredible detail. Further the astronauts practice the actual labor for hours & hours here on earth before the real thing.

This is not like preplanned repair work in space. Any inconsistency or innaccuracy in the composition or application of a "shield patch" could result in dissapatory or expansion rate/extent changes with potentially disasterous consequences. All this without considering the potential for additional damage caused by the astronaut performing the repair. At this juncture nothing is safe. Repairing the damage might kill them.

NASA is facing a very unpleasant decision about what course of action is least liekly to result in the deaths of the crew.


RE: Hmm
By sprockkets on 8/14/2007 5:17:57 PM , Rating: 2
They remove and inspect every tile, and replace as necessary.


How common is this?
By timmiser on 8/14/2007 5:20:15 PM , Rating: 2
I think one important fact that is missing from this story is the failure of the media to ask or NASA to advise how often damage such as this has occured on shuttle flights in the past? Only recently we've started going over the shuttle tiles with a magnifying glass after each launch but before the Columbia disaster, something like this wouldn't be noticed until the shuttle landed.

My question is for those that repair the tiles after each launch for the last 25 years, how common is it to have a gouged tile such as this? I would think the heat shield tile experts on the ground have would know right away if this is something to be concerned about.




RE: How common is this?
By bespoke on 8/14/2007 5:35:16 PM , Rating: 2
Exactly. There has to have been a similar strike sometime in the past. Hopefully they've kept records...


RE: How common is this?
By jpmills on 8/14/2007 6:04:43 PM , Rating: 3
You can find the reports about debris on this server http://ntrs.nasa.gov/ and do a search for debris and shuttle flight such as sts-57. There are reports filed after every flight. The orbiter returns pretty dinged up every flight.
Here, for example is the one for STS-84 http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.g...
Look at page 54.


RE: How common is this?
By timmiser on 8/14/2007 6:23:28 PM , Rating: 1
Which is my point. How does this rate in the 25 year history of "dinged up" shuttles?


RE: How common is this?
By jpmills on 8/14/2007 7:48:24 PM , Rating: 2
Well, STS-110 had 18 hits over 1-inch in size on the lower surface with 110 hits total over the whole orbiter.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.g...


RE: How common is this?
By kemche on 8/14/2007 7:11:26 PM , Rating: 2
Thanks for the link. I never knew that they kept detail records of every single events.

Cool


RE: How common is this?
By SiliconAddict on 8/14/2007 8:13:01 PM , Rating: 2
Umm no. NASA inspects the heat shield after every mission. They have done this from the start.


Fill that sucker in
By zerocool84 on 8/14/2007 4:36:45 PM , Rating: 1
Why don't they just go to Home Depot and fill that sucker in with some Great Stuff foam. That stuff works wonders.




RE: Fill that sucker in
By PrinceGaz on 8/14/2007 6:50:56 PM , Rating: 1
They might not have any of it aboard this Shuttle, or on the ISS it is docked with, and launching another Shuttle or a Soyuz to fly some up would not be cost effective ;)


RE: Fill that sucker in
By kemche on 8/14/2007 7:14:02 PM , Rating: 4
There is no Home Depot in Space.


RE: Fill that sucker in
By Alexvrb on 8/14/2007 8:14:34 PM , Rating: 2
Ah, but there IS a Space Auto Parts. A can of Inferno exhaust repair goop should git er done!

"Space Auto, this is Doug. Muffler mend? Do you have a charge account with us? No? I hope you've got cash. No checks either? Well get NASA on the line and get a Visa number, and call us back. We'll shuttle it over after the card clears."


RE: Fill that sucker in
By SiliconAddict on 8/14/2007 8:17:06 PM , Rating: 2
Main Entry: 1hu·mor
Pronunciation: 'hyü-m&r, 'yü-
Function: noun

a : that quality which appeals to a sense of the ludicrous or absurdly incongruous b : the mental faculty of discovering, expressing, or appreciating the ludicrous or absurdly incongruous c : something that is or is designed to be comical or amusing


"weight"
By mjcutri on 8/14/2007 5:03:22 PM , Rating: 2
I think you may be mistaken about the "weight" of the suit.
"The current generation of space suit is a large 300-pound suit that is hard to maneuver in -- not to mention the 150 pounds of tools that the astronaut will have with him."

That may be the weight on the earth's surface, but weight is relative to your location. A more correct terminology would be to use mass. (which in this case would be 9.32 slugs (136 kg) for the suit and 4.66 slugs (68 kg) for the tools.




RE: "weight"
By gibbsk on 8/14/2007 5:05:57 PM , Rating: 2
It's still clunky, no matter where you are...


RE: "weight"
By PrinceGaz on 8/14/2007 6:48:55 PM , Rating: 3
It's just inertia. Without gravity, there is no desperate rush to do anything on a space-walk (though obviously staying out too long increases the likelihood of micro- or not so micro- meteorites impacting), and the only effort involved is in accelerating and decelerating objects (whilst maintaining your own position), and overcoming suit-stiffness.

That's why spacewalks usually last a few hours, and not the few minutes you see in movies. Without a jet-pack and a motorised suit, spacewalks are necessarily slow procedures. I guess that is why they are called space-WALKS, rather than something more indicative of rapid movement.


Newly refitted shuttle...
By SandmanWN on 8/15/2007 11:06:46 AM , Rating: 2
You would figure that a shuttle that has spent this much time being retrofitted would have a better system for fixing damaged tiles. Seriously, how difficult would it be to have a tile system that is more easily replaceable and to keep a set number of said tiles aboard for such an event?

Perhaps Im oversimplifying a bit but after 25 years of recorded history of impacts to the heat shield you would think all the brainiacs at NASA could solve this little caveat or at least devise a suitable replacement scheme that could be accomplished more easily in space.

I'm sure someone will point out that the shuttle is due for retirement but is that any excuse to put our astronauts at risk? Would make more sense to me to at least attempt a new heat shield on a currently working design and gain valuable knowledge for the next implementation of space vehicle.




RE: Newly refitted shuttle...
By Chernobyl68 on 8/15/2007 4:51:21 PM , Rating: 2
it took a couple years worth of chemical engineering, mechanical engineering, material science, aerospace engineering, to come up with the tiles in the first place. you want them to come up with a completely new way of thermally protecting the shuttle from the heat of re-entry in a couple months? it can't be done.
the best they have is come up with a method of making MINOR repairs while in orbit. by the way, the tile shape probably prevented the damage being greater - who knows how far the cracks would have propogated if instead there had been one big heat shield. and face it, you have no idea what you're talking about anyway.


RE: Newly refitted shuttle...
By SandmanWN on 8/15/2007 5:11:48 PM , Rating: 2
couple of months? The space shuttle Endeavor hasnt flown a mission in 5 years!!! This problem didnt pop up yesterday you know.


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