Images of Endeavour's Damaged Tiles

Roland Piquepaille writes "Neptec Design Group, a Canadian company and a NASA prime contractor for 25 space missions, was kind enough to send me exclusive images of Endeavour's damaged tiles during its last take-off. So here are some of these pictures" The pictures are pretty amazing and make the urgency of this whole thing much more amazing.

Comments

How long has this been happening?

[GodfatherofSoul]

This kind of damage MUST have been occurring throughout the history of the program. And, if it has been NASA would have been aware during the regular retiling of the Shuttle. My question is why wasn't the ice impact problem wasn't addressed long ago.

Re:How long has this been happening?

[SomeGuyTyping]

from Wikipedia (http://en.wikipedia.org/wiki/Space_Shuttle_extern al_tank):

Development of the ETs thermal protection system has been problematic, and has proven a fatal weakness to shuttle mission safety. NASA has had difficulty preventing fragments of foam from detaching during flight, ever since a 1995 decision to remove chlorofluorocarbon-11 (CFC-14) from the composition of the foam in compliance with an Environmental Protection Agency ban on CFCs under section 610 of the Clean Air Act. In its place, a hydrochlorofluorocarbon known as HCFC 141b was certified for use and phased into the shuttle program. The "new" foam containing HCFC 141b was first used on the aft dome portion of ET-82 during the flight of STS-79 in 1996. Use of HCFC 141b was expanded to the ETs acreage, or larger portions of the tank, starting with ET-88, which flew on STS-86 in 1997.

Re:How long has this been happening?

[Mr. Slippery]

environmentalist groups got their way and now we have a riskier space program.

This point about how the foam insulation process was changed has come up many times in discussions about the damage to Endeavor. And it's wrong.

It has its origin in one of Rush Limbaugh's lies. As it turns out, the foam that dealt Columbia the death blow was the old-style CFC foam. The problem was in the hand-spraying application method used on that area, which left gaps and voids in the foam.

Yes, when they first started using the CFC-free foam in 1997 there were some problems seen. Changes were quickly made to improve the adhesion.

There were also plenty of problems with the CFC foam - "popcorning" from trapped air bubbled was noted in 1995, while in 1992 Columbia was struck by a large piece of foam, ripping a 12cm gouge in the tiles. Both of these were before the switch to CFC-free foam.

Re:How long has this been happening?

[tgd]

But his overall point is quite correct -- every single shuttle mission came back with missing and damaged tiles.

Most of the shuttle is not under the same level of thermal load as the front edges of the wings during re-entry. Columbia got unlucky that the damage was at the worst possible spot.

Its a bad design, but the whole shuttle is an awful design. Most of the time it works, though.

IMO, this is a reaction to Columbia and a dramatically reduced interest in the shuttle program. For ten years launches barely got reported. Its nice (for the continuance of the shuttle program) for people to be talking about it.

Plus, for those who haven't seen a shuttle tile up close, they're not very big. Thats not a six inch gash in there.

Re:How long has this been happening?

[icebrain]

It's more like the engineers got hamstrung by the Air Force and the beancounters. Original shuttle plans called for a fully-reuseable vehicle with a more robust thermal protection system. The beancounters promoted the half-disposable design we have now, claiming it would reduce costs, and contrived studies to show that it would be much more reliable than it actually turned out to be. They also screwed around with the budgeting, eventually causing even more cost overruns, delaying the development, and forcing compromises that made the vehicle less safe.

The Air Force wanted manned space capability, and offered to help pay for the development if they got some say in the design and were allowed use of the shuttles when built. The USAF insisted on a larger payload bay (60ft long, as opposed to NASA's 40ft plan), which obviously made the vehicle larger. They also wanted the ability to land at the launch site after a single polar orbit, requiring 1000+ miles of crossrange. This led to the heavier delta wing and higher reentry heating loads.

We wound up with a vehicle that was larger, more expensive, and less safe than we should have. The engineers did the best they could under the political mandates they were given.

Re:How long has this been happening?

[Retric]

The problem with the shuttle is not any specific design decision it's the overall design goals which the "top-end engineers at NASA" had little to do with.

"The crucial factor in the size and shape of the Shuttle Orbiter was the requirement that it be able to accommodate the largest planned spy satellites, and have the cross-range recovery range to meet classified USAF mission's requirement for a one-around abort for a polar launch." The most obvious bad design decision was to send cargo up in a manned mission. Manned vehicles cost a lot more per pound sent to space than unmanned so mixing the two increases the cost of sending stuff to orbit with zero real gain. The other issue is the requirement for a polar orbit. (Think Russia) Getting people to space is hard but doable getting people to space and a polar orbit is a much harder task that is a waste of resources 99% of the time.

Second "Each Shuttle was designed for a projected lifespan of 100 launches or 10 years' operational life." However, Discovery was built in 1985 its last flight is scheduled for 2010.

If you want a cheep reusable rocket rebuild the shuttle with 5% its cargo capacity, a slow reentry, and skip the polar orbit concept and you get a much larger safety margin and a much less extreme operating environment and a lower cost per person to orbit.

Re:How long has this been happening?

[MarsDefenseMinister]

Both of the deadly shuttle accidents are directly attributable to the side-by-side nature of the orbiter and the fuel tanks and SRB's. This design should have been discarded. If the shuttle were stacked vertically, these particular failures would have been impossible.

Re:Err on the side of caution...don't you think?

[datan]

maybe we should leave the rocket scientist stuff to real rocket scientists...

Re:Err on the side of caution...don't you think?

[grommit]

You do realize that the Shuttle has landed many times before the Columbia disaster with whole tiles missing. This most likely is a non-issue although I'm glad NASA is treating it seriously. Besides, these tiles are on the belly of the orbiter. The damaged RCC panels on Columbia were on the leading edge of a wing where there are greater temperatures on reentry.

I don't think you realize the inherent danger in attempting to fix these either.

Re:Err on the side of caution...don't you think?

[Anonymous Coward]

It always amuses me how the masses sitting on the sidelines always feel they can do better then the trained professionals. I'm assuming you've already done the calculations between risk of the loss of them doing a spacewalk vs tile damage, where the tile is positioned, and taken into account the fact before Columbia that tiles fell off without incident. I could be wrong, but I'm just as qualified as you are. So is the guy I bought a hotdog from yesturday for that matter.

This would be like my mom telling me she can do computer support better then me. She's a smart lady, but her KNOWLEDGE level when it comes to Computers is low.

wrong

[everphilski]

Oh, and for another tidbit. Ice, since its denser, and heavier than the insulating foam, is a bigger problem than the foam is when it breaks off. It takes a smaller chunk of ice to break off and smack the orbiter to cause an equivalent amount of damager to a larger chunk of foam.

Foam does more damage than ice. Ice is dense and keeps its velocity high, which translates to a low velocity relative to the shuttle. Foam on the other hand is much less dense and slows down very quickly, translating to high velocities relative to the shuttle.

Remember, kinetic energy = 0.5 * mass * V^2. Velocity is what kills, not mass.

Re:Without a scale...

[Volante3192]

Astronauts have balls of steel to begin with. Two sets. You're sitting, surrounded by just how much in explosive fuel? Blasted into one of the most uninhabitable climates for human survival. (Ranks up there with volcano caldera and bottom of ocean...) Then set on a 100 mile free fall course to the Earth, the same trip many meteors take, and burn up well before hitting the ground most of the time.

And yet I so want to do it for myself...