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.
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.
Very good point. I remember back in the early 80's news reports of the shuttle coming back with 1/3rd of the tiles being gone due to faulty glue. Even when they didn't need to repalce the tiles so much, I'm sure they HAD to go over every inch with a fine tooth comb, and I'm sure that more than once they found some with holes from damage, either ice or micrometers. This whole "omg teh tiles have holes in them' thing is a reaction to the columbia disaster, and a way to show the media that 'yes, we are aware of the issue'.
Turn in your geek card. It wasn't the 80's, and the shuttle wasn't coming back because it hadn't been to space. It was the Enterprise, it was the 70's, and it was during the development of the shuttle.
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.
If you think that hundreds of engineers sitting down and designing it is how the Shuttle came into existance in the early 70's, you should go read up on some history of NASA.
The shuttle design (and the program) is one set of bad decisions after another made for corporate welfare and political reasons shoehorned through Congress based on a huge number of known lies (like the shuttle-launch-a-week they claimed they'd have). It was continued as a way of getting to the Space Station, even though the construction of it was delayed 15 years.
There were dramatically better designs considered during the 70s that would've been cheaper and more reliable, but wouldn't impact various Senator's home states as much. There were bad decisions made even after the Shuttle was picked (using aluminum skin not titanium, which is why the heat shield is needed anyway).
Seriously. Read some histories of the shuttle program. You'll learn why it happened and not the Apollo-based Mars mission, why the Saturn V (and future solid fuel boosted versions) were dropped in favor of a much more expensive per pound STS.
NASA has smart engineers. Thats why the design for the shuttle's replacement looks nothing like the shuttle. Its also a big reason why the Buran was killed in the USSR, and the Soviets/Russians dominated manned space flight for 25 years.
Buran was dropped due to a lack of funds because of the collapse of the Soviet Union, which left their space program strapped for cash.
Although Buran was essentially a copy of the Shuttle, the Soviet engineers were able to surmise its shortcomings and address those issues. For starters, it wasn't as vulnerable to the mess we had with Columbia, and are having again with Endeavour.
The crew compartment was supposedly reinforced and structurally isolated from the rest of the ship, suggesting that a Challenger or Columbia type disaster could have been potentially survivable.
Buran was launched piggybacked on an Energia booster (which is the closest thing Russia had to a Saturn V) -- economies of scale suggest that this would have been cheaper in the long-run, not to mention that it kept a large multi-purpose launch vehicle in Russia's "arsenal", something which the US currently lacks (not to mention that an Energia could have sent up huge portions of the ISS in one go, rather than expensively constructing it bit by bit as we are doing now.
Buran could fly and land automnously. The space shuttle gained this ability only recently, and to my knowledge, it's never been attempted. This combined with the continuation of the Soyuz program hypothetically allows the crew to stay aboard Mir/ISS, and return via a Soyuz capsule, while the Shuttle lands on its own in the case that it was damaged during takeoff, and would be risky to land.
I wouldn't be terribly surprised if NASA uses a similar strategy to get the crew of Endeavour home.
It still wasn't a great idea all in all, but it made a hell of a lot more sense than the Shuttle does. Kliper [wikipedia.org] looks very promising at the moment, and may be a "best of both worlds" compromise between traditonal capsules and shuttle-type craft.
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.
The half-disposable design was a direct result of the military's insistence on increasing the payload carrying capacity by an order of magnitude combined with cutbacks in original funding targets. The increased size caused other design issues for re-entry and landing. It was also to have been replaced roughly 10 years ago.
Hence you have the bloated obsolete pig we use today.
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.
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.
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.
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 [mediamatters.org].
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 [newscientist.com], 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.
Limbaugh says "there's a theory going around" and after explaining it says "a lot of people are beginning to think that the banning of Freon actually caused the shuttle accident, the Columbia shuttle accident, two flights ago. And I'm inclined to believe it when I hear this." This was on August 3rd, according to media matters. At this point the NASA report had not been released yet--it wouldn't be fully released for months! There was nothing to lie about!
Can someone really "lie" when they say "there's a theory I'm inclined to believe" ?
But I suppose it's just much easier to hysterically claim that Rush Limbaugh both originated the theory AND lied about it that to actually read your own link though!
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.
It isn't momentum, again, it is kinetic energy that causes damage, KE = 0.5 * m * V^2. The velocity, squared, overcomes the density difference in short order. Again, go do some research on Columbia. It is consensus that foam did the damage.
Ignoring air resistance, which won't be much different for similarly-shaped pieces, once detached from the shuttle, pieces of ice and foam would accelerate towards the ground at the same rate.
You can't ignore air resistance at low altitudes (the impact happened in the first 2 minutes) at supersonic speeds! Acceleration due to gravity is negligible due to the timeframe, we are talking fractions of a second. So for similarly shaped pieces, the drag force will be similar. The lighter piece, foam being much lighter than ice, will slow down very quickly. Now we approach the shuttle which has not slowed down. We have a large speed differential between the foam and the shuttle, whereas between the ice and the shuttle, there is very little speed difference.
On NPR this morning, I heard that NASA was actually debating whether or not to even address this, as they did not want to go to all the trouble and spoil the shuttle's schedule.
This sounded especially insane to me...if NASA loses another shuttle because of this same tile-damage problem, and because they couldn't be bothered to take the time to fix the problem when they could have, it will be the end of NASA.
by Anonymous Coward
on Wednesday August 15 2007, @09:24AM (#20236299)
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.
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.
I still feel strongly that they should attempt a repair, in this case.
First and foremost - if there is a small chance of catastrophic loss of vehicle, then measures should be taken to prevent that.
But Secondly - and possibly more importantly; how many more shuttle flights will there be? What if there is more serious damage on the next flight? And we still have never tested the repair techniques?
I think that this damage is a perfect opportunity for NASA to do what it does best: testing new aerospace technologies - and in this case, repair of shuttle heat-shield damage. The repair job will be a great opportunity to learn new EVA skills and techniques. After the shuttle is safely down, the repair job can be studied, and evaluated for how it held up during re-entry, and I think that is valuable science that wouldn't otherwise be done.
To *not* repair this damage, is short-sighted in two ways: It's hoping that the damage to Endeavor isn't fatal, and it's hoping that the next mission to get damaged, also does not require repairs, and if it does, that we will get the repair right the first time, when we've never ever done anything remotely like it before.
The tile was then passed from student to student. As I said above, it was as hard as ceramic and as light as styrofoam. Even if an astronaut hit a tile deliberately with a sharp instrument, it is unlikely they could damage it.
I'm not sure what your teacher was showing you, but the Shuttle tiles are quite
definitely fragile. See these articles:
If by any chance you do need to contact the tile with your hands, we would require only gentle hand reaction alone. We want you to distribute the load over several fingers or the backs of the fingers. Source [spaceflightnow.com]
[The tile is] a rather soft piece of material. You can easily scratch it with your
fingernail. It has... a very thin layer of fiberglass on the outside. It's a fabulous insulator and
NASA gave it to us to use as an insulator for an experiment we were doing. We were working at
high temperatures and needed an extremely good insulator.
So I had this tile sitting on my desk and it was a curiosity all along. And then it became much
more meaningful when I realized that, gee, it wouldn't be very difficult at all to damage this. I
could probably, with my finger, break through it.
Source [princeton.edu]
The only known technology in the early 1970s with the required thermal and weight characteristics was also so fragile, due to the very low density, that one could easily crush a TPS tile by hand. Source [wikipedia.org]
They are in the wind tunnel doing test studies on a similar gouge crafted from the laser data taken on Monday. The Shuttle people know what they are doing. You have to remember, this gouge was downgraded from the size stated earlier this week, its only about the size of a business card, half the size that was being reported on Monday and less a quarter of the size that was thought to have dealt Columbia in.
You also have to consider position. This is at the very rear of the vehicle. Reentry heating evironm
Perhaps I'm missing something (and I'm sure I am), but perhaps this is something of a blessing?
Leave Endeavour in orbit. Compared to the big-mother boosters, the shuttle itself does not require a lot of fuel, and given the smaller size of the next-generation craft we're looking at, I could see a use for a "space truck" the size of Endeavour, even after the shuttle program does out the door.
I could see a use for a "space truck" the size of Endeavour, even after the shuttle program does out the door.
Oh sure, but you know how it is. As soon as your buddies find out you have a space truck they'll want you to help move their space sofas into their new space condo.
The reason for the landing gear part is because that is a 1 shot deal. The Shuttle must be going less than 300kts when the gear is deployed. And there is no 'retract'. Once the gear is deployed, that's it. It can only be raised in ground operations. And you cannot reenter with the gear down. And after reentry, above 300kts you might tear the gear off. If the computer burps at the wrong time, scratch one shuttle. For just about every other problem, there is a workaround. Fire the reentry rockets at the wrong
I like the fact that our society is open enough that this information and this debate is public. There are many governments in this world today who would not allow this information to be released and would make the decision based on cloaked objectives and goals. The USA has its problems (e.g. the stupidity of Iraq) but it sets us apart that this is happening in the open. Nobody is going to get arrested for debating or questioning this intense and sensitive topic.
Thank you for your comment. It has been analyzed and approved by the NSA and the CIA. A copy of your comment (and your voting record) will be kept on backup indefinately at our Langley VA storage facility.
Without a scale to compare to, the gouge looks HUGE and devastating.
I've heard on the radio that they are discussing a roughly 3" scrape....which, if scaled to the longest axis, is objectively pretty small, but when considered against the turbulence, heat, and pressure that those belly tiles are faced with? It looks huge and devastating again.
Those astronauts have balls of steel if they ride that thing down again.
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.
OK, what's the original quote, and was it Shepard or Glenn? Or was this just too good a line for any of the Right Stuff mob to pass up?
"When reporters asked Shepard what he thought about as he sat atop the Redstone rocket, waiting for liftoff, he had replied, 'The fact that every part of this ship was built by the low bidder.'"
"I felt about as good as anybody would, sitting in a capsule on top of a rocket that were both built by the lowest bidder." (Senator John Glenn, Colonel USMC, Retired)
"It's a very sobering feeling to be up in space and realize that one's safety factor was determined by the lowest bidder on a government contract." -- Alan Shepard.
by Anonymous Coward
on Wednesday August 15 2007, @09:35AM (#20236449)
Those are some dinky little low resolution pics. Here's one of Endeavor with the Earth as backdrop [nasa.gov], today's NASA "Image of the day". Yesterday's [nasa.gov] is spacewalking astronaut Rick Mastracchio fixing something outside the space station. Here it is [nasa.gov] taking off, and here's another liftoff pic. [nasa.gov] These are all of the present mission that's still up there inspecting tiles. Here [nasa.gov] is the "Image of the day" gallery. These are bigassed, high resolution pictures, most of them breathtaking.
What's interesting is how delicate the tiles are. I saw a presentation by a NASA guy some time ago and I was allowed to hold the tiles. They're extremely light, almost feeling like their core is some kind of foam. The black ceramic layer on top is surprisingly thin.
I asked the presenter specifically about how delicate they felt. He then "flicked"/snapped the tile with his finger/fingernail, which put a sizeable dent into the tile, easily cracking the brittle black layer, and you could see the white foam underneath.
Therefore, it's no surprise to me to see this kind of damage. It probably wasn't even impacted with what could be considered excessive force.
Makes you wonder what kind of tile damage shuttles had -- all those successfully landed shuttle missions -- before such close scrutiny.
It's sad that we have to do this on EVERY launch when we had developed a perfectly good system where the heat shield was covered for the entire time it wasn't in use.
What, precisely, was wrong with the capsule system that necessitated the development of something that can *gasp* glide to a landing? How have we saved money by building a reusable craft when it costs a billion dollars a launch?
"...was wrong with the capsule system that necessitated the development of something that can *gasp* glide to a landing? "
Size, risk, recovery costs. Well, when you calculate the cost of a single use capsule that can make deliveries to the Space Station, launch satellite, used to repair satellites, THEN you can do a cost analysis. Saying we have or have not 'lost' money compared to some non-existent thing, or that using a capsule wouldn't have cost more lives is a logical fallacy.
If they're typical tiles and they haven't drastically changed things from the demo they have down in Florida that I looked at 10 years ago, they're 3 or 4 inches on a side. The NPR story this morning said the gouge was 3" long.
It looks borderline to me. I think they've successfully landed with much bigger gouges or missing tiles in the past, but it probably depends on WHERE the gouge is. If it's in a flat part of the belly, it's probably not a problem. If it's near a leading edge, more of a problem.
How long has this been happening? (Score:5, Interesting)
Re:How long has this been happening? (Score:5, Insightful)
Parent
Re:How long has this been happening? (Score:4, Informative)
Parent
Re:How long has this been happening? (Score:5, Interesting)
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.
Parent
Re:How long has this been happening? (Score:5, Interesting)
The shuttle design (and the program) is one set of bad decisions after another made for corporate welfare and political reasons shoehorned through Congress based on a huge number of known lies (like the shuttle-launch-a-week they claimed they'd have). It was continued as a way of getting to the Space Station, even though the construction of it was delayed 15 years.
There were dramatically better designs considered during the 70s that would've been cheaper and more reliable, but wouldn't impact various Senator's home states as much. There were bad decisions made even after the Shuttle was picked (using aluminum skin not titanium, which is why the heat shield is needed anyway).
Seriously. Read some histories of the shuttle program. You'll learn why it happened and not the Apollo-based Mars mission, why the Saturn V (and future solid fuel boosted versions) were dropped in favor of a much more expensive per pound STS.
NASA has smart engineers. Thats why the design for the shuttle's replacement looks nothing like the shuttle. Its also a big reason why the Buran was killed in the USSR, and the Soviets/Russians dominated manned space flight for 25 years.
Parent
Re:How long has this been happening? (Score:5, Interesting)
Buran was dropped due to a lack of funds because of the collapse of the Soviet Union, which left their space program strapped for cash.
Although Buran was essentially a copy of the Shuttle, the Soviet engineers were able to surmise its shortcomings and address those issues. For starters, it wasn't as vulnerable to the mess we had with Columbia, and are having again with Endeavour.
The crew compartment was supposedly reinforced and structurally isolated from the rest of the ship, suggesting that a Challenger or Columbia type disaster could have been potentially survivable.
Buran was launched piggybacked on an Energia booster (which is the closest thing Russia had to a Saturn V) -- economies of scale suggest that this would have been cheaper in the long-run, not to mention that it kept a large multi-purpose launch vehicle in Russia's "arsenal", something which the US currently lacks (not to mention that an Energia could have sent up huge portions of the ISS in one go, rather than expensively constructing it bit by bit as we are doing now.
Buran could fly and land automnously. The space shuttle gained this ability only recently, and to my knowledge, it's never been attempted. This combined with the continuation of the Soyuz program hypothetically allows the crew to stay aboard Mir/ISS, and return via a Soyuz capsule, while the Shuttle lands on its own in the case that it was damaged during takeoff, and would be risky to land.
I wouldn't be terribly surprised if NASA uses a similar strategy to get the crew of Endeavour home.
It still wasn't a great idea all in all, but it made a hell of a lot more sense than the Shuttle does. Kliper [wikipedia.org] looks very promising at the moment, and may be a "best of both worlds" compromise between traditonal capsules and shuttle-type craft.
Parent
Re:How long has this been happening? (Score:5, Insightful)
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.
Parent
Re:How long has this been happening? (Score:4, Interesting)
Hence you have the bloated obsolete pig we use today.
Parent
Re:How long has this been happening? (Score:5, Insightful)
"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.
Parent
Re:How long has this been happening? (Score:5, Insightful)
Parent
Re:How long has this been happening? (Score:5, Informative)
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.
Parent
Re:How long has this been happening? (Score:5, Informative)
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 [mediamatters.org]. 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 [newscientist.com], 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.
Parent
Re:How long has this been happening? (Score:4, Insightful)
Limbaugh says "there's a theory going around" and after explaining it says "a lot of people are beginning to think that the banning of Freon actually caused the shuttle accident, the Columbia shuttle accident, two flights ago. And I'm inclined to believe it when I hear this." This was on August 3rd, according to media matters. At this point the NASA report had not been released yet--it wouldn't be fully released for months! There was nothing to lie about!
Can someone really "lie" when they say "there's a theory I'm inclined to believe" ?
But I suppose it's just much easier to hysterically claim that Rush Limbaugh both originated the theory AND lied about it that to actually read your own link though!
Parent
wrong (Score:5, Informative)
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.
Parent
Re:[AC]wrong (Score:5, Informative)
Parent
Re:wrong (Score:4, Interesting)
You can't ignore air resistance at low altitudes (the impact happened in the first 2 minutes) at supersonic speeds! Acceleration due to gravity is negligible due to the timeframe, we are talking fractions of a second. So for similarly shaped pieces, the drag force will be similar. The lighter piece, foam being much lighter than ice, will slow down very quickly. Now we approach the shuttle which has not slowed down. We have a large speed differential between the foam and the shuttle, whereas between the ice and the shuttle, there is very little speed difference.
Parent
Re: (Score:3, Informative)
Sure, if you redesign the entire thing. That tail sticking up kinda screws that idea.
That way any impacts from ice or foam would strike surfaces not critical for reentry.
'Non critical'. Like the windshields, flight controls, thinner skin of the body. Non critical stuff like that.
Endeavour: (Score:5, Funny)
Re: (Score:3, Funny)
Re:Endeavour: (Score:4, Funny)
Riding the TGV to hell.
Parent
Err on the side of caution...don't you think? (Score:4, Insightful)
This sounded especially insane to me...if NASA loses another shuttle because of this same tile-damage problem, and because they couldn't be bothered to take the time to fix the problem when they could have, it will be the end of NASA.
Re:Err on the side of caution...don't you think? (Score:5, Insightful)
Parent
That was the problem (Score:3, Funny)
Re:Err on the side of caution...don't you think? (Score:5, Insightful)
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.
Parent
Re: (Score:3, Funny)
Poll: Preferred Shuttle Heat-Shield Repair Technology
Re:Err on the side of caution...don't you think? (Score:5, Informative)
I don't think you realize the inherent danger in attempting to fix these either.
Parent
Re:Err on the side of caution...don't you think? (Score:5, Interesting)
First and foremost - if there is a small chance of catastrophic loss of vehicle, then measures should be taken to prevent that.
But Secondly - and possibly more importantly; how many more shuttle flights will there be? What if there is more serious damage on the next flight? And we still have never tested the repair techniques?
I think that this damage is a perfect opportunity for NASA to do what it does best: testing new aerospace technologies - and in this case, repair of shuttle heat-shield damage. The repair job will be a great opportunity to learn new EVA skills and techniques. After the shuttle is safely down, the repair job can be studied, and evaluated for how it held up during re-entry, and I think that is valuable science that wouldn't otherwise be done.
To *not* repair this damage, is short-sighted in two ways: It's hoping that the damage to Endeavor isn't fatal, and it's hoping that the next mission to get damaged, also does not require repairs, and if it does, that we will get the repair right the first time, when we've never ever done anything remotely like it before.
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Re:Err on the side of caution...don't you think? (Score:4, Informative)
The tile was then passed from student to student. As I said above, it was as hard as ceramic and as light as styrofoam. Even if an astronaut hit a tile deliberately with a sharp instrument, it is unlikely they could damage it.
I'm not sure what your teacher was showing you, but the Shuttle tiles are quite definitely fragile. See these articles:
Rich.
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Re: (Score:3, Insightful)
You also have to consider position. This is at the very rear of the vehicle. Reentry heating evironm
Is it so urgent? (Score:3, Interesting)
Leave Endeavour in orbit. Compared to the big-mother boosters, the shuttle itself does not require a lot of fuel, and given the smaller size of the next-generation craft we're looking at, I could see a use for a "space truck" the size of Endeavour, even after the shuttle program does out the door.
Just send up something else to bring them home.
Re: (Score:3, Funny)
The Space Shuttles are more like "space tubes."
Re:Is it so urgent? (Score:5, Funny)
Oh sure, but you know how it is. As soon as your buddies find out you have a space truck they'll want you to help move their space sofas into their new space condo.
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Re: (Score:3, Informative)
For just about every other problem, there is a workaround. Fire the reentry rockets at the wrong
Exclusive images? (Score:5, Informative)
Exclusive? Yeah right... (Score:5, Funny)
--
Capitalism: When it uses the carrot, it's called democracy. When it uses the stick, its called facism.
Direct link to the images. (Score:5, Informative)
Image 1 [blogsforcompanies.com]
Thermal Image [blogsforcompanies.com]
Image 2 [blogsforcompanies.com]
Image 3 [blogsforcompanies.com]
Image extracted from a video made by Neptec LCS [blogsforcompanies.com]
A good public debate (Score:5, Insightful)
Re: (Score:3, Funny)
Without a scale... (Score:4, Interesting)
I've heard on the radio that they are discussing a roughly 3" scrape....which, if scaled to the longest axis, is objectively pretty small, but when considered against the turbulence, heat, and pressure that those belly tiles are faced with? It looks huge and devastating again.
Those astronauts have balls of steel if they ride that thing down again.
Re:Without a scale... (Score:5, Insightful)
And yet I so want to do it for myself...
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... and built by the lowest bidder (original?) (Score:5, Interesting)
"When reporters asked Shepard what he thought about as he sat atop the Redstone rocket, waiting for liftoff, he had replied, 'The fact that every part of this ship was built by the low bidder.'"
"I felt about as good as anybody would, sitting in a capsule on top of a rocket that were both built by the lowest bidder." (Senator John Glenn, Colonel USMC, Retired)
"It's a very sobering feeling to be up in space and realize that one's safety factor was determined by the lowest bidder on a government contract." -- Alan Shepard.
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*Yawn* (Score:3, Informative)
-mcgrew
Delicate tiles (Score:5, Informative)
I asked the presenter specifically about how delicate they felt. He then "flicked"/snapped the tile with his finger/fingernail, which put a sizeable dent into the tile, easily cracking the brittle black layer, and you could see the white foam underneath.
Therefore, it's no surprise to me to see this kind of damage. It probably wasn't even impacted with what could be considered excessive force.
Makes you wonder what kind of tile damage shuttles had -- all those successfully landed shuttle missions -- before such close scrutiny.
Roland Piquepaille? (Score:3, Insightful)
Ol' Bricks and Wings (Score:3, Interesting)
It's sad that we have to do this on EVERY launch when we had developed a perfectly good system where the heat shield was covered for the entire time it wasn't in use.
What, precisely, was wrong with the capsule system that necessitated the development of something that can *gasp* glide to a landing? How have we saved money by building a reusable craft when it costs a billion dollars a launch?
Re: (Score:3, Interesting)
Size, risk, recovery costs. Well, when you calculate the cost of a single use capsule that can make deliveries to the Space Station, launch satellite, used to repair satellites, THEN you can do a cost analysis. Saying we have or have not 'lost' money compared to some non-existent thing, or that using a capsule wouldn't have cost more lives is a logical fallacy.
Re: (Score:3, Insightful)
It looks borderline to me. I think they've successfully landed with much bigger gouges or missing tiles in the past, but it probably depends on WHERE the gouge is. If it's in a flat part of the belly, it's probably not a problem. If it's near a leading edge, more of a problem.
Re:The solution. (Score:5, Funny)
Word! Pass dat pipe, homie.
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Re:[AC]THIS IS INSANITY! (Score:3, Informative)
Whens the last time the Europeans have launched humans into space? *crickets*
April 10, 2007 (Score:4, Informative)
http://en.wikipedia.org/wiki/Soyuz_TMA-10 [wikipedia.org]
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