STS-114 Mission Coverage and Discussion

Palomar · 2005-07-28 12:32:04

*The human impact:

Shuttle Grounding May Cause Layoffs
AP - 1 hour, 23 minutes ago
MICHOUD, Louisiana - The grounding of the space shuttle program following NASA's problems with insulating foam raised fears of layoffs at the Louisiana plant where the foam is applied. The plant supplies about 2,000 jobs, many of them high-paying, to the economically depressed city of Michoud, on the edge of New Orleans. "It's very depressing. We're concerned about our jobs, our livelihoods," said Mike Berger, an inspector for the foam application process who has worked at the Michoud Assembly Facility since 1980.

Is archived at Yahoo! news. Sad.

--Cindy

GCNRevenger · 2005-07-28 12:49:46

I take the opposite view. Closed cell foam will always shed something. It rapidly ascends into extremely low pressure while travelling at hypersonic speads. Foam is closed cell, there's no way it could withstand the drop in pressure, the cells will burst. I suspect this chunk of foam loss was due the an area of the bypod no longer covered with foam. The edge of foam below the bipod got caught in hypersonic air and was torn off. So the latest loss of foam was due to the change in foam.
The reason I say that I take the opposite view, is that NASA has grown a glass jaw. This foam didn't strike the orbiter at all and no damage was done, yet they grounded the orbiter. WHAT!? If there was damage I could understand that, but when there isn't any damage?
New designs won't have these problems. As we discussed, "The Stick" won't have an external tank at all, and the SRB segment seals with rubber O-rings won't have a liquid hydrogen tank beside them. The Challenger or Columbia accidents can't happen. The SDVs won't have any tiles so don't care if foam comes off. These problems will go away with future vehicles.
The orbiter itself has been improved to deal with foam issues. The white tiles have been replaced by thermal blankets. Foam just bounces off blankets. Black HRSI tiles are being replaced by attrition by FRCI tiles that are 3 times as strong vs. impact damage. They happen to be 10% lighter but more expensive. They're new, thermal blankets and FRCI didn't exist when the shuttle was first built. Last night I talked to one individual who said RCC gets pitted during use. NASA has a protocal to fill holes up to 1/4" diameter rather than replacing the piece. The guy I talked to doesn't think the pits have been sufficiently studied to determine if patched tiles are strong enough to withstand foam impact. If that's it then replacing patched RCC tiles with new ones will make them immune to foam. This is the trick, make tiles strong enough rather than trying to stop foam from coming off. The orbiter has had dings in its tiles since the very first flight, STS-1.

I think you are coming from a completly wrong direction Robert, you have your head screwd on in the same fasion as the "plug dike with gum" External Tank project office. Your post is also filled with particularly poor supposition and assumptions with an overall unfounded overconfidant attitude.

Why should closed cell foam rupture? How do you know that it does? Styrafoam taken down to the bottom of the ocean will compress to a fraction of its volume, but even under such intense pressure, the cells won't collapse for at least most of the decent. This polyurethane foam is stronger with smaller cells, why should it? Speculation.

"If there was damage I could understand that, but when there isn't any damage?"

Nonsense! If the foam detached just a little sooner, then we may have a Columbia 2.0 on our hands! I find your view of the matter to be beyond the pale, large foam chunks have damaged the orbiter several times now, once fatally! How can you say that???

"Black HRSI tiles are being replaced by attrition by FRCI tiles that are 3 times as strong vs. impact damage."

No they aren't I don't think, they are only being replaced in the lower heating regions of the shield, and not at the peak heating regions, because FRCI tiles have higher thermal conductivity and hence are unsuitable. I would double-check your facts... anyway, I question if FRCI tiles are strong enough to avoid being damaged by foam any more then the regular ones. The regular ones are so fragile that you can crush them in your hand easily, three times an impact strength of zero is still almost zero. To say nothing of a micrometeroid or orbital debries collision.

"If that's it then replacing patched RCC tiles with new ones will make them immune to foam."

How do you know that? Do you know that? And even if it is, we must assume that you are wrong until we do... I doubt it, a small pit like that really is pretty small, and the pannels themselves have undergone extensive testing, including acoustics, which would detect fractures in the pannel that could weaken it. NASA isn't going to come up with a new pannel material either, RCC is the only stuff available that works... I don't think that NASA can even produce new pannels anymore. I find your statement to speak volumes of your wrongheaded mindset and wishful thinking.

I will close concerning Shuttle by reaffirming that your thinking is just like that of the incompetant engineers at NASA which have nearly destroyed another Shuttle because of their "oh, it'll be okay" Challenger-style mindset. I personally do not think that the Space Shuttle tiles can ever be strengthend enough to realiably, safely resist damage from signifigant foam impacts.
-------------------------------------------------------------------------------------

Now for the nontechnical issues...

Considering all the challenging engineering feats that NASA claims that they can accomplish that VSE will require, I really don't think that the goal of preventing dangerous foam shedding from the tank - particularly given how low-tech its insulation is - is unreasonable. At least for Michoud, infact I think that this should be a qualification test for their involvement in VSE, if they can't do something this realtivly simple, then they have no business being in the rocket business anymore.

You have consistantly focused on particular dike-plugging issues in your post, but ignored my problem with the overall competance issue. Disreguarding any particular program or project, I question if Michoud is competant to build CEV capsules and/or Shuttle-Derived cores as M. Griffin has promised them. I think that the documentation and quotes from Michoud external tank office/officers shows that they don't take this as seriously as they should, nor have they changed following the Columbia tragedy as is demanded of them, despite the fact that it was even their fault that these men and women are dead because of them!

This is one problem that won't go away just by changing the project these clowns are working on.

GCNRevenger · 2005-07-28 12:51:51

*The human impact:
Shuttle Grounding May Cause Layoffs
AP - 1 hour, 23 minutes ago
MICHOUD, Louisiana - The grounding of the space shuttle program following NASA's problems with insulating foam raised fears of layoffs at the Louisiana plant where the foam is applied. The plant supplies about 2,000 jobs, many of them high-paying, to the economically depressed city of Michoud, on the edge of New Orleans. "It's very depressing. We're concerned about our jobs, our livelihoods," said Mike Berger, an inspector for the foam application process who has worked at the Michoud Assembly Facility since 1980.
Is archived at Yahoo! news. Sad.
--Cindy

Oh is that so Michoud people... Well I'm worried about your shoddy work killing more astronauts! To say nothing of America's future in space, and the tens of thousands of other NASA employees who rely on your work.

Somebody call up Boeing and see if they can make an 8.5m version of their Delta-IV tanks as a replacement.

idiom · 2005-07-28 14:05:12

Question: If the tiles all have to be inspected and removed and reglued and whatnot each flight, how are they better than a replaceable ablative shield?

Granted the tiles are more 'advanced' and so keep more people employed but they don't seem to keep the flight rate up at all.

GCNRevenger · 2005-07-28 14:14:43

Probobly too heavy, the tiles are pretty light weight.

Not all the tiles are removed between flights either I don't think, only damaged or at risk ones.

Such a signifigant redesign isn't going to happen in any practical time frame before the 2010 deadline for any reasonable sum of money either.

RobertDyck · 2005-07-28 19:51:15

Only damaged tiles are replaced. Tiles aren't completely lost when damaged, they break so either a chip is missing or at worst only a chip is left. Tiles are foam silica fiber with the consistency of styrofoam. Black tiles have a glaze, that's what makes them black and that glaze radiates heat. One NASA employee I talked to said only about 100 tiles are replaced between each flight. He also said it takes 1 person day to replace a tile: remove the old tile, clean the aluminum skin, replace the felt, glue on a new tile. But there's also the inspection to determine where tiles have to be replaced. I think it's too much labour. Spending that much time inspecting and replacing tiles defeats the point.

I also read a document that claims HRSI tiles are being replaced by attrition by FRCI tiles. The NASA guy I talked to didn't think so, but I hope it's true. FRCI tiles can handle 100°F more heat, are 10% lighter, and most importantly can withstand 3 times as much impact force before breaking. If I had my way they would analyze where the orbiter can't afford to loose a single HRSI tile and replace those with FRCI. Be pro-active, it's a buzz word but better than loosing an orbiter.

As for the foam: um, didn't they remove the foam ramps before the cut-out around the bipod? That means hypersonic air flow across the edge of foam aft of the bipod. If high speed air gets under the foam edge it'll tear out foam; then it'll peal back. It looks like that's what happened.

RobertDyck · 2005-07-28 20:28:19

I think you are coming from a completly wrong direction Robert, you have your head screwd on in the same fasion as the "plug dike with gum" External Tank project office. Your post is also filled with particularly poor supposition and assumptions with an overall unfounded overconfidant attitude.

Not unfounded; they spent 2.5 years redesigning the Shuttle. It better be safe after that much time. I'm tired of sitting waiting for human exploration of Mars, let's get on with it!

Why should closed cell foam rupture? How do you know that it does? Styrafoam taken down to the bottom of the ocean will compress to a fraction of its volume, but even under such intense pressure, the cells won't collapse for at least most of the decent. This polyurethane foam is stronger with smaller cells, why should it? Speculation.

Call it speculation if you must, but your example is poor. If styrofoam is formed up here at 1 atmosphere pressure, cells will form with gas at 1 atmosphere. Taking it down to ocean depths will crush it but cells will collapse due to lack of pressure. Bringing it back up will restore pressure to the size the cells formed so they will inflate back to initial size. If you form the foam at high pressure, let the polymer set, then reduce pressure further the cells must expand rather than contract. But set polymer foam cells can't expand much, if you reduce pressure to 1/10th atmosphere the gas must expand 10 times. That expands bubble surface area to 4.64 times. Volume increases as the cube of diameter, surface by square, so the square of the cube root of 10. There's no way a set polymer foam can expand to 4.64 times the surface area; it'll burst. And I don't believe for a moment that spray foam will have cells with enough bubble surface area strength to hold 1 atmosphere pressure; foam bubbles are just too thin. Teflon FEP film 1 mil thick has bursting pressure of 11 psi, an atmosphere is 14.69 psi and foam cells are much thinner than 1 mil with a lot of variation. I doubt the foam used is as strong as Teflon FEP.

"If there was damage I could understand that, but when there isn't any damage?"
Nonsense! If the foam detached just a little sooner, then we may have a Columbia 2.0 on our hands! I find your view of the matter to be beyond the pale, large foam chunks have damaged the orbiter several times now, once fatally! How can you say that???

I don't like the current Shuttle design, but we're stuck with it. We won't get a better system until the ISS is finished and the best way to finish ISS is with Shuttle. I came up with a Shuttle-C/orbiter combination that completes it quickly, but that still relies on the Shuttle. If you don't like my idea then we're stuck with Shuttle. A 3-tonne unmanned tug with an end effector like CanadArm would cost more to develop. Any alternative would cost more. This shuttle flight was a success; let's call it that and get going.

"If that's it then replacing patched RCC tiles with new ones will make them immune to foam."
How do you know that? Do you know that? And even if it is, we must assume that you are wrong until we do... I doubt it, a small pit like that really is pretty small, and the pannels themselves have undergone extensive testing, including acoustics, which would detect fractures in the pannel that could weaken it. NASA isn't going to come up with a new pannel material either, RCC is the only stuff available that works... I don't think that NASA can even produce new pannels anymore. I find your statement to speak volumes of your wrongheaded mindset and wishful thinking.

The person I spoke with Wednesday night isn't an engineer, he's a medical doctor. He claims there never was a study to determine safe pit size for RCC panel pitting, the 1/4" size was arbitrary. I've seen some arbitrary decisions in my day so the accusation is feasible. I don't know if it's so, only this one person made the claim, but it's something that I want NASA to look at.

The RCC panels are very strong, no one believed a piece of foam could damage them. Engineers were sure only LRSI and HRSI tiles would be affected by foam. They replaced LRSI tiles by FRSI and AFRSI thermal blankets that are immune to foam hits. The thermal blankets happen to be lighter and cheaper as well. We must compliment Ames for developing them. So only HRSI tiles (black tiles) were the worry. Why did a leading edge RCC panel break? If it's just weakening due to patching pits as this medical doctor claims, then replacing patched panels is an easy fix.
---
I'll get to non-technical issues myself.

The U.S. government has demonstrated a repeated habit of failing to address problems until someone gets killed, then over-reacting and causing more damage than the accident or initial failure to act. Don't ground the Shuttle for another 2.5 years simply because a strip of foam ripped off. It didn't cause any damage and the Shuttle is fine. Yes, it requires examining the design. A ramp like the one they removed would prevent the strip of foam coming off. Yes, you could say the fix caused this loss. But you want to exclude Michoud from making tanks for SDV!? The SDV won't have anything that could be damaged by foam, so loss of foam is irrelevant. This is the exact over-reaction that I mean. Cancelling SDV simply because of this foam would cause much more damage than the foam caused Discovery. We could debate the best form of SDV, but cancelling any SDV would prevent a manned mission to Mars within our lifetime.

GCNRevenger · 2005-07-28 20:41:05

Obviously its too much work, and too much margin for human error, but what else is NASA supposed to use? No other material exsists that is as light weight and effective that I know of. This is one of the cheif flaws associcated with the design concessions made to the USAF during Shuttle's conception, that the long cross-range ability means higher heat loading over a smaller area.

FRCI tiles, the "new heavy duty tiles," may be able to resist higher temperatures but that is only half the story of their effectiveness as a heat shield, you must also consider their thermal conductivity. Which if it is inferior to HRSI tiles, if these are the tiles referred to in the newspaper articles, then they can't be used for half the Shuttle's underbelly. Again, simply stating that they are "three times stronger" is quite irrelevent, the real question remains is how strong are they compared to foam or other debries impact.

If you can replace half of Shuttle's 15,000 odd tiles with the new ones, thats twenty man years of work per orbiter. That many tiles won't come cheap either... For a marginal improvement over a portion of the less vunerable part of Shuttle's hull? I don't like that deal.

"...didn't they remove the foam ramps before the cut-out around the bipod? That means hypersonic air flow across the edge of foam aft of the bipod. If high speed air gets under the foam edge it'll tear out foam; then it'll peal back. It looks like that's what happened."

Supposition again, and not very likly at that. NASA did CFD studies on the tank during the redesign, and why would the air get under the PAL ramps? They are down away from the bipod around the curvature of the tank. And even then, the air flow will be predominantly parallel to the PAL ramp edge, not perpandicular needed to cause the damage. Its awfully far down away from the interstage too.

Why do you not believe the simplest and most likly explanation? That this foam is applied just like the old bipod foam that killed Columbia was, and so it fell off for the same reason: manufacturing defect.

My beef with the Michoud people is that their own studies showed that the PAL ramps were unnessesarry, and given their track reccord with manually applied foam (which has been proven to damage the Orbiter repeatedly), why were they not removed?

SpaceNut · 2005-07-28 20:54:48

Not to take away from the discusion of foam debri but there are important steps being preformed with shuttle and the ISS on this mission.

These do needed to be mentioned.
Canadian Arm and laser inspection process:
Statement by Marc Garneau, President, Canadian Space Agency Return to Flight Mission STS-114
To which I am thank full that such a tool was made.

Shuttle carries solar cells into space

Solar cells developed by a team of scientists, including one from Ohio State, were launched into space Tuesday aboard the space shuttle Discovery. The cells may one day help power a manned mission to Mars.
The cells are high efficiency, lightweight solar cells using new material technology. They consist of thin layers of compound semiconductor materials whose optical properties are tailored to capture most of the sun's energy within a thickness of less than three micrometers, Ringel said.

Well if all the data proves out the design this is a bug step in lowering the cost to orbit at least for these energy supplying tool.

These last few bug me in the same way that the continual foam falling off does.
2 Area Firms Work To Get Shuttles Flying Again

NASA's decision Wednesday to ground its space shuttle fleet to analyze the continuing problem of foam debris breaking off upon launch could mean more business for two area companies.
Raindrop Geomagic in Durham created the software NASA is using to measure the extent of the damage to the Space Shuttle Discovery.

ISU Studied Foam for Shuttle last month
Well if they have done such a complete job at finding the Nasa created defects then why not the actual tank problems?

Shuttle flaws test NASA's toolbox prowess

While it sure is the right step forward to be able to patch or to fix the shuttle while in orbit. The tank is the item that still needs fixing....

Now, with the realization that 2-1/2 years and $1.4 billion of research and repair did little to solve the foam problem that destroyed the shuttle Columbia

While it is not the full amount of sitting idle for this time period it is still way to much for not fixing the problem.

Here are a few thoughts for the foam:
How about deviding the thick layer of foam onto seperate applications with an elastic like membrane between each application sort of like your car windshield.
The next would be to apply the foam in a near vacum to allow for less air pressure with in the closed cells of the foam.
And if the ramp repair is the suspect as Rob indicates. Why not added a bolt on air diverter flange or cover ramp over the leading edge of the area behind the ramps.

Commodore · 2005-07-28 21:04:03

I don't like the current Shuttle design, but we're stuck with it. We won't get a better system until the ISS is finished and the best way to finish ISS is with Shuttle. I came up with a Shuttle-C/orbiter combination that completes it quickly, but that still relies on the Shuttle. If you don't like my idea then we're stuck with Shuttle. A 3-tonne unmanned tug with an end effector like CanadArm would cost more to develop. Any alternative would cost more. This shuttle flight was a success; let's call it that and get going.

Sounds a lot like Russian Roulette to me.

The story that NASA's foam trouble has gotten alot worse since switching to non-freon-applied foam for environmental reasons back in 97' apears to be true as well. NASA's incompetance is becomming more and more staggering... please explain why we are not using the freon-based foam? You know, the foam that would have reduced the liklihood of killing the Columbia crew which you knew fell off the tank and damaged tiles previously?

I'm glad someone brought this up cause I heard it as well. And I fear you answered your own question. The EPA decided that freon based foam was not environmentally friendly, and probably with a little prodding from the Clinton administration, NASA agreed to switch.

GCNRevenger · 2005-07-28 21:49:40

"Not unfounded; they spent 2.5 years redesigning the Shuttle. It better be safe after that much time."

No. The onus was on NASA to prove that Shuttle was acceptably safe again, not on the doubters to prove that it wasn't, and NASA failed again.

"I don't believe for a moment that spray foam will have cells with enough bubble surface area strength to hold 1 atmosphere pressure; foam bubbles are just too thin."

I don't think you know what you are talking about here... if this was the case, then why doesn't the foam disintegrate during acent? The thickness of the polymer layer is not the only factor determining the maximum pressure it can withstand, the interconnected morphology of the foam is self-supporting. Plus, the bubbles are VERY small when applied properly. And, the foam is probobly formulated with a high tensile strength, which may very well be tougher then the ordinarily quite rubbery Teflon for foam applications.

"don't like the current Shuttle design, but we're stuck with it."

Your "darn the torpedos, full speed ahead" philosophy is what I have a problem with. It has been lethally demonstrated that large chunks of foam are an unacceptable risk to Shuttle. Unacceptable meaning that the chance of damage is so high, that NASA cannot responsably trust a crew to the thing, much less risking the priceless pieces of hardware. Until this flaw is corrected, and corrected for real this time, this is the case.

The fact that damage didn't occur on Discovery this time is irrelivent: the launch proved that the same type of unacceptable risk exsists from the same type of source. This Shuttle flight was a test of the safety of the STS system, and it failed the test badly, with a near-miss of an almost identical situation to the event that destroyed Columbia. Hence M. Griffin ordering the grounding of the fleet. Since there are no alternatives available at the moment, then work will simply have to cease.

"The RCC panels are very strong"

Well apparently this is not the case. Testing would have revealed fractures in the panneling caused by pitting that could weaken it, and as far as I know the current set of pannels passed the testing. Therefore, the pannels as designed are not strong enough to resist serious foam strike, and so the only way to return Shuttle to flight is to eliminate serious foam shedding. Period.

Replacing the pannels is not as easy as you say either, I was under the impression that NASA no longer has a source of replacement pannels, only a few spares left. They had to rip one off of Atlantis for the foam testing even.
------------------------------------------------------------

"Don't ground the Shuttle for another 2.5 years simply because a strip of foam ripped off. It didn't cause any damage and the Shuttle is fine."

You are greviously understating the problem: foam shedding from the tank DID cause damage, several times! One of which was Columbia... here, see, this is a perfect example of the "plug dike with gum" mindset: pointing to this one spot (PAL ramp) and ignoring the overall picture just like what nearly destroyed Discovery on Tuesday. NASA needs to fix ALL the foam, not focusing on any particular spot, and changes that don't address all of the even slight risks of dangerous shedding are incomplete. The fact remains that Michoud applied foam in an identical way to the kind that killed Columbia and put it in a hazardous place.

"But you wan't to exclude Michoud from making tanks for SDV!?"

The problem isn't with risk of foam to SDV, the problem is that the Michoud staff are, until I see otherwise, incompetant, and shouldn't be building anything. And that includes SDV cores or CEV capsules. I have already said this! Why can you not accept that the incompetance of their staff is the REAL problem? I would like to reiterate, that preventing dangerous foam shedding and treating the program with the appropriate level of seriousness were reasonable expectations to demand from them for their future participation in manned spaceflight.

And they flunked the test, badly

I don't care if it means delaying a Mars mission by several years while NASA builds a new light/medium HLLV, if Michoud is incompetant, which appears to be the case, then they shouldn't be building rockets. Period.

RobertDyck · 2005-07-28 22:18:15

I keep talking about Earth orbit rendezvous for both Lunar and Mars. That means launching crew in a separate vehicle. The SDV doesn't have to be man ranted. Furthermore, the problem isn't with foam itself; it's with foam hitting tiles. If the vehicle doesn't have any tiles the tank can loose all the foam it wants and still be safe.

As for Shuttle: the big picture is that Shuttle launched with an arm extension boom that permitted inspection on-orbit, and a tile patch kit. Even if tiles were lost they could be replaced. That wasn't necessary so the damaged HRSI and FRCI tiles that were brought in the cargo bay will be used for practice.

Yang Liwei Rocket · 2005-07-29 02:45:38

Probobly too heavy, the tiles are pretty light weight.
Not all the tiles are removed between flights either I don't think, only damaged or at risk ones.
Such a signifigant redesign isn't going to happen in any practical time frame before the 2010 deadline for any reasonable sum of money either.

The Shuttle is a very complicated machine, there are big risks with it. However it has seen some damage in the past and flown home safely.

The problem is if the damage is in a critical point, they have been inspecting the Shuttle and can now use the ISS as a safe area while they work out what to do.
NASA have said this is only a test flight, they make have to re-work Shuttle and the ground and don't know if that's a month, or if that's three months.
The biggest danger is having damage at critical points on the Shuttle

You can inspect some of the Shuttle here

http://www.nasa.gov/images/content/1237 … 05_med.jpg

http://www.nasa.gov/images/content/1237 … .jpg]scuff on Shuttle ?

http://www.nasa.gov/images/content/1237 … 05_med.jpg
http://www.nasa.gov/images/content/1237 … 05_med.jpg

http://www.nasa.gov/images/content/1237 … 5_med.jpg] Shuttle pic

http://www.nasa.gov/images/content/1237 … 05_med.jpg

idiom · 2005-07-29 06:03:34

Probobly too heavy, the tiles are pretty light weight.

You're saying that a re-usable heat shield is lighter than an expendable one? I would not have guessed that.

If foam cells are having issues at low pressure, could they be sprayed in a partial vacuum?

How weight sensitive is the plan to get the ISS loaded? Could a tonne or so of payload mass be spared from each flight to wrap the tank in something realiable? Is every flight packed to the eyeballs with cargo or is there room to spare?

BWhite · 2005-07-29 06:25:40

I keep talking about Earth orbit rendezvous for both Lunar and Mars. That means launching crew in a separate vehicle. The SDV doesn't have to be man ranted. Furthermore, the problem isn't with foam itself; it's with foam hitting tiles. If the vehicle doesn't have any tiles the tank can lose all the foam it wants and still be safe.

Exactly

Palomar · 2005-07-29 07:37:36

*Statement by Eileen Collins:

Discovery commander surprised by debris problem
Reuters - 57 minutes ago
HOUSTON - Shuttle Discovery commander Eileen Collins said on Friday she was surprised the flying debris problem that brought down Columbia in 2003 re-emerged on their flight and said shuttles should not return to space until it was fixed. She and astronaut Andy Thomas said in press interviews from space they were not worried about damage the debris may have caused Discovery, saying the orbiter looked "very clean" despite a few nicks to its protective tile.

Looks very clean. Seems optimistic. Quote from Yahoo! news.

--Cindy

C M Edwards · 2005-07-29 07:38:12

Here's a suggestion:

When they first started launching space shuttles, the tanks had a coating. (Remember, they used to be white, not orange?) NASA could try going back to that, only with the use of cloth or a PVC coat instead of mere paint.

Here's another suggestion:

If the material damage to the space shuttle is bad enough, this latest incident (newly revealed foam strikes on the leading edge of Discovery's wings) could kill both the space shuttle and ISS at one blow. If none of the crew dies with them, then that's not necessarily a bad thing in the long term. Half of the NASA budget would go away, too, but that money isn't being spent on anything except shuttle and ISS now anyway. If any portion of the lost shuttle and ISS budget can be diverted into something useful, NASA could start moving forward again.

It might be best to sacrifice Discovery.[/i]

GCNRevenger · 2005-07-29 07:56:12

I keep talking about Earth orbit rendezvous for both Lunar and Mars. That means launching crew in a separate vehicle. The SDV doesn't have to be man ranted. Furthermore, the problem isn't with foam itself; it's with foam hitting tiles. If the vehicle doesn't have any tiles the tank can loose all the foam it wants and still be safe.
As for Shuttle: the big picture is that Shuttle launched with an arm extension boom that permitted inspection on-orbit, and a tile patch kit. Even if tiles were lost they could be replaced. That wasn't necessary so the damaged HRSI and FRCI tiles that were brought in the cargo bay will be used for practice.

The problem with SDV and foam isn't the foam falling and damaging the vehicle, its that the people that build the thing are incompetant, and foam still falls off even after $1,500,000,000 dollars and 5,000 man-years or work were poured into the ET office with one primary goal: stop serious foam shedding. And they failed, infact that failed miserably by the look of it, and that they still aren't taking the problem seriously enough to do the job right even when astronauts ARE riding on the thing. Until they shape up and enact the post-Columbia philosophies demanded of them, some heads roll as pennance and as example too perhaps, then they are simply the wrong people for the job.

The tile repair capability is an untested, last-resort, emergency measure. And, they can't fix ALL the tiles with their super-caulk reliably, like gluing landing gear hatches shut by mistake. This is a terrible reason for excusing the foam & tile problem!

http://www.cnn.com/2005/TECH/space/07/2 … x.html]CNN article

It also looks like Discovery may have had a much closer call then you think... there were actually three pieces of foam sighted, a softball-sized piece may have struck the wing. Had this piece been a little larger...

Shuttle is never going to be able to reliably withstand foam strikes from large pieces, that is just wishful thinking, so the only solution is not to try and fail to armor Shuttle or worse yet pretend and reassure outselves that it actually can take it without radical redesign, which Columbia disproved. The foam shedding problem has to be fixed, period. If Michoud can't do this, then they can't be trusted to do anything.

GCNRevenger · 2005-07-29 10:17:39

Probobly too heavy, the tiles are pretty light weight.
You're saying that a re-usable heat shield is lighter than an expendable one? I would not have guessed that.
If foam cells are having issues at low pressure, could they be sprayed in a partial vacuum?
How weight sensitive is the plan to get the ISS loaded? Could a tonne or so of payload mass be spared from each flight to wrap the tank in something realiable? Is every flight packed to the eyeballs with cargo or is there room to spare?

The "non reuseable" shield material is probobly an ablative coating like the Apollo capsules; ablative coatings work by intentionally burning/boiling off the coating, which is a process that consumes and carries away heat that would otherwise destroy the vehicle. In order to protect a vehicle the size, mass, and trajectory of Shuttle, you would need a large mass of ablative material. So yes, the glass tiles are probobly lighter. Such a design change would without a doubt ruin Shuttle's payload capability, and would take some years to develop at the cost of tens of billions of dollars.
------------------------------------------------------------

Technically speaking, the first thing that Michoud ought to do is eliminate ALL manually applied foam on the orbiter half of the tank. Period, no ifs ands or buts, and the "foam sprayer guys" put out to pasture. Step two would be to switch back to freon as a blowing agent, EPA and greenies or not. Step three would be to wrap the tank with a fiber mesh or polymer coating, which would not be that difficult, and tell KSC that they just have to find some payload to ditch somehow. Or switch to the bigger five-segment type boosters from ATK, but that is unlikly.

Non-technically speaking, Sandy Colemen would be terminated, immediatly along with the managers/engineers that aproved the tank redesign, and the first step (of many, which I am sure will be needed) is that the decision to aprove the design be taken out of Michoud's hands. The decision about putting manually applied foam, the same type that killed Columbia, in a dangerous place when you did not need it or a non-foam alternative exsisted is inexcusable. The folks at KSC who beat the post-Columbia "anti-Challenger" safety philosophies into the staff there would be taking a little business trip to Lousiana too... Coleman's nonchalant attitude about "won't our computer models be great after Discovery flies?" is a VERY clear sign that Michoud is still in the pre-Columbia/pre-Challenger mindset.
------------------------------------------------------------

As much as I would like to see M. Griffin give up on Shuttle/ISS, I think realisticly the return to flight has progressed too far to stop it now. The political costs of canceling Shuttle/ISS were too high after Columbia, and the huge embarrasment for NASA/Bush at pulling the plug after Discovery's flight make the price even higher. NASA is running on borrowed credibility, and if it uses that little bit up then NASA is finished... Though I hate the idea, NASA has to get Shuttle flying again and end the program honorably, or they're doomed.

Palomar · 2005-07-29 13:22:57

NASA is running on borrowed credibility, and if it uses that little bit up then NASA is finished... Though I hate the idea, NASA has to get Shuttle flying again and end the program honorably, or they're doomed.

http://news.yahoo.com/s/ap/20050729/ap_ … Y-]Griffin assembling "tiger team"...

*...is aiming for another shuttle launch by year's end. He's taking full responsibility. Also says it won't be a long, drawn-out affair.

I like Michael Griffin.

--Cindy

RobertDyck · 2005-07-29 13:36:58

If you want to beat up the greenies, get an EPA exemption for N2O4. According to Encyclopedia Astronautica, in 1959 NASA would buy carload lots of 1-ton cylinders for $0.15 per kg. By 1990 NASA was paying $6.00 per kg due to environmental regulations.

In 1959 the price for MMH was $15 per kg. It was projected that this would be reduced to $2.00 per kg in mass production. By 1990 NASA was actually paying $17.00 per kg due to stringent environmental protection regulations.

GCNRevenger · 2005-07-29 13:58:02

Said "tiger team" better not include any Michoud folks, and be of the attitude "get out of the way and let the real rocket scientists through" rather than going out of their way to preserve their self-esteem... or their employment.

I bet that they are just going to rip off the PAL ramps and call it good though, it would take some kind of miracle to do the job right in four or five months. Somebody had better lose their jobs over the PAL ramp debacle though.

NASA needs Shuttle and needs it soon, but that is little excuse for M. Griffin to keep flying Shuttle with a half-fixed external tank. If it can't be fixed, then the responsable thing to do is not fly Shuttle again, period.
-------------------------------------------------------------------------------------

Robert: I really couldn't care less about how much RCS/OMS fuel costs, since it is such a tiny fraction of the total cost of a launch. My issue with the environmentalists is, that NASA bowed to their freon-phobia and the Michoud people didn't take their jobs seriously enough and ensure that the new foam was just as good.

Palomar · 2005-07-29 14:03:56

Said "tiger team" better not include any Michoud folks, and be of the attitude "get out of the way and let the real rocket scientists through" rather than going out of their way to preserve their self-esteem... or their employment.
I bet that they are just going to rip off the PAL ramps and call it good though, it would take some kind of miracle to do the job right in four or five months. Somebody had better lose their jobs over the PAL ramp debacle though.
NASA needs Shuttle and needs it soon, but that is little excuse for M. Griffin to keep flying Shuttle with a half-fixed external tank.

*I was surprised to see that from Yahoo! news (in my previous post) after reading http://www.spacedaily.com/news/shuttle- … html]*this article*

"NASA says it will never stop debris falling from shuttle."

So why continue?

There's yet another headline (just now recalled; I see it in the "Spacedaily Express" section) "NASA says foam -might- have struck Discovery's wing."

Geez. Guess we'll find out August 7.

--Cindy

RobertDyck · 2005-07-29 14:10:14

Could we contain foam using the same spray-on film as Audi now uses for car bodies? GCNRevenger, you're a polymer scientist; what's your professional opinion?
Link: http://www.audiworld.com/news/02/spray/ … l]Spray-on Protection for Vehicles in Transit

idiom · 2005-07-29 14:12:49

What would a carbon fiber lamination of the Tank cost? (weight wise... you could build it out of Gold cheaper, but it would be to heavy...)

Such a lamination would allow you to cheap out on internal load carrying structure wouldn't it? To stop foam it would only need to be a single layer, but you could go to sandwhich construction with carbon foam coating and a chewy lithium alloy centre and maybe not gain any weight? Better than being really careful about spraying the foam.

New Mars Forums

Announcement

#151 2005-07-28 12:32:04

Re: STS-114 Mission Coverage and Discussion

#152 2005-07-28 12:49:46

Re: STS-114 Mission Coverage and Discussion

#153 2005-07-28 12:51:51

Re: STS-114 Mission Coverage and Discussion

#154 2005-07-28 14:05:12

Re: STS-114 Mission Coverage and Discussion

#155 2005-07-28 14:14:43

Re: STS-114 Mission Coverage and Discussion

#156 2005-07-28 19:51:15

Re: STS-114 Mission Coverage and Discussion

#157 2005-07-28 20:28:19

Re: STS-114 Mission Coverage and Discussion

#158 2005-07-28 20:41:05

Re: STS-114 Mission Coverage and Discussion

#159 2005-07-28 20:54:48

Re: STS-114 Mission Coverage and Discussion

#160 2005-07-28 21:04:03

Re: STS-114 Mission Coverage and Discussion

#161 2005-07-28 21:49:40

Re: STS-114 Mission Coverage and Discussion

#162 2005-07-28 22:18:15

Re: STS-114 Mission Coverage and Discussion

#163 2005-07-29 02:45:38

Re: STS-114 Mission Coverage and Discussion

#164 2005-07-29 06:03:34

Re: STS-114 Mission Coverage and Discussion

#165 2005-07-29 06:25:40

Re: STS-114 Mission Coverage and Discussion

#166 2005-07-29 07:37:36

Re: STS-114 Mission Coverage and Discussion

#167 2005-07-29 07:38:12

Re: STS-114 Mission Coverage and Discussion

#168 2005-07-29 07:56:12

Re: STS-114 Mission Coverage and Discussion

#169 2005-07-29 10:17:39

Re: STS-114 Mission Coverage and Discussion

#170 2005-07-29 13:22:57

Re: STS-114 Mission Coverage and Discussion

#171 2005-07-29 13:36:58

Re: STS-114 Mission Coverage and Discussion

#172 2005-07-29 13:58:02

Re: STS-114 Mission Coverage and Discussion

#173 2005-07-29 14:03:56

Re: STS-114 Mission Coverage and Discussion

#174 2005-07-29 14:10:14

Re: STS-114 Mission Coverage and Discussion

#175 2005-07-29 14:12:49

Re: STS-114 Mission Coverage and Discussion

Board footer