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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.
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.
I swear to God...I swear to God! That is NOT how you treat your human!
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.
Just send up something else to bring them home.
"You can either have software quality or you can have pointer arithmetic, but you cannot have both at the same time."
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.
-Styopa
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?
I'm in the hole of the broadband donut.
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.
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.
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.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
greater tempreatures AND pressure differentials. at the leading edges the pressure differential from outside the wing to the inside is HUGE a gap will cause the heat to be sucked into the wing area. Basically the problem happened because everything that could have gone wrong and caused the failure, happened. It was bad damage, and was at a location that enhanced the problem during reentry.
Honestly it could be fixed with a loss of payload capacity, put in an emergency ablative system in place, a set of mixture tanks and nozzles that when temperatures rise to dangerous levels fire and fill both wings with rapidly expanding foam that acts as an ablative firestop AND insulation to the rest of the structure. You might lose 15% of the wing but it will be structurally safe enough to get you to the ground. I believe they even looked at such a solution as well as the newer fireproof coatings used on buildings to protect the metal during an intense blaze(another ablative fire protection put as paint) to be applied inside the entire win structure.
Problem is, reducing the payload capacity is not an option.
Do not look at laser with remaining good eye.
This isn't really an issue of insulation. It's the disturbance of laminar flow. The laminar boundary layer is actually quite a good insulator itself, especially at Mach 20. The main issue is how much the hole disturbs the boundary layer and what localized heating might result. This small of a hole in diameter, even though it's mostly through the tile, should be mostly negligible. But NASA is treating it VERY seriously and is doing simulations as well as has an arc-jet facility to test on an exact duplicate of the damage. (It's a 3D model of the hole, if you check the video, and is easily reproduced on the ground. It has even been printed out with a 3D printer.)
Remember that Columbia damage was on the Reinforced Carbon-Carbon (RCC) panels on the leading edge of the wing, not the tiles on the belly. The leading edge is one of the hottest and most critical points where that damage occurred. This damage is generally low risk, and EVA is always risky to some degree, but this might be a great opportunity to test repair procedures. When people talk about whether NASA is making decisions based on schedule for this damage, it's not about ignoring risks for the sake of schedule. Risk wins, easily. The schedule issue is that if the damage is not a risk at all, is it prudent to fix it anyway to test procedures and have an actual flow repair to analyze upon return. Remember, EVA and extending flights adds risk to the crew too, but can be beneficial and reduce risk both for this flight and future flights.
I don't specialize in fluid or thermodynamics but this is my opinion, and any support/rebuttal is welcome!
h tm shows the area around the hole endures about 10 minutes of 1500 deg F heat, and Google tells me aluminum melts at 1220 deg F. On the surface (pun intended), this would seem cause for concern.
A quick check on re-entry temperature variation on this site: http://www.columbiassacrifice.com/$D_temperature.
If NASA engineers feel these tiles can re-enter without repair, their reasons could be:
1) This area of the shuttle does not have to contend with the extreme heat that is experienced at the nose or other leading edge surfaces so the "hot air" isn't hot enough to melt the aluminum in the belly, and
2) The hole must be small enough that hot air flow may "skip" over it on re-entry. If the hot air can indeed passes right over it, then the danger to the aluminum inside is probably not very great.
If the engineers ran a "simplified" mathematical simulation assuming the hole was just the "average" well-formed hole, the above rationale would make sense.
I think the more important concern to focus on (which I'm sure NASA must have considered), is that this hole is very asymmetric. The photos provide terrific evidence. One side the gash slopes gently into the "hole" (I presume where the depth sensor reads 1.2 inches, since the tiles are only 1 inch thick), and on the other side, you have a quarter ping-pong ball cut-out as well as a 90-degree lip of half-tile above the hole. In this instance, I think the direction of travel of these tiles on re-entry matters a great deal... I think the first scenario below may be most cause for concern.
1) If the "up" orientation of the tile lettering is the shuttle's forward direction, I would imagine the hot air flow will not be turbulent upon entering the gash, and will actually follow the gentle slope downwards towards and into the hole, melting what is inside. What hot air doesn't make it into the hole will smack into the 90-degree lip and the quarter ping-pong ball cut-out, causing excess heat at those edges and/or loosening that tile from its backing, causing it to fall off (though not too likely since that lip represents only a small portion of that tile, and it is buttressed by the other tiles "behind" it).
2) On the other hand, if the forward direction was reversed, the hot air flow would become turbulent upon meeting the quarter ping-pong ball cut-out. If the dimensions of that cut-out are sufficiently disruptive, the turbulent hot air could "lick" the hole, melting whatever is inside, what doesn't go into the hole will glide off the sloped ceramic gouge on the other side. With the turbulent air, there will be a negative air pressure around that tile, but the force shouldn't be enough to rip the tile from its backing.
If the shuttle direction is that of option #1, let's hope that hole is small enough that as litte hot air gets in as possible.
My point is this: A hole is not just a hole unless it looks the same from all sides...
Nowadays they spend more money and time examining their own machinery than examining the space.
While I'm sure the holes in the tiles of the shuttle is not part of NASA's plan I think it's actually a very useful part of the mission.
We need to get beyond this whole concept of sending up the best and the brightest and throwing gobs of money at the program. We need to get to the point where we will have establishments (most likely lunar at first) where we're going to have real workers and not just high end engineers.
The idea of doing maintenance in space is going to be part of this future colonization. Being able to know how to do real work in this environment is going to bring us much closer to those goals. If we're yanking people out of a space station or colony every time the slightest maintenance needs done we're going to be paying big bucks with little return.
The lessons learned with the tiles on the shuttle and the heavy maintenance schedule of the Mir are going to take us a long way in establishing real working environments instead of just clean room type experiments.
Dedicated Cthulhu Cultist since 4523 BC.