Michoud External Tanks May Hold Clue About Columbia Accident

Nasa, Michoud ^ | 2/4/2003 | Joseph Ranos

[Sonar5]

Michoud, Michoud, Nichoud. You will learn that name like you did with Martin Marrietta as it relates to Challenger.

This can be a very confusing issue to undestand. If you have a question, I will be happy to answer it, but if you are confused about something I wrote, Please ask me about it, and I will clarify the context for you. Thanks.

I have been working on this since yesterday morning. I am just linking my discussions on other boards so that you can see what I have found. Others have contributed to these findings, so you have to be willing to follow the links and take a few hours to fully grasp its contents.

I am a licensed Private Pilot-Single Engine Land.

My original hypothesis was posted here: http://www.flightsimnetwork.com/dcforum/DCForumID2/4703.html

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In it I wrote: My Own research of course. Follow Closely now. I am 100% Serious, and I am not trolling, so please don't flame me, as I believe I am on to something here.

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ET = External Tank

LWT = Light Weight Tank

SLWT - Super Light Weight Tank

***********************************

I was involved in a thread on flightsim here: http://www.flightsimnetwork.com/dcforum/DCForumID2/4703.html

In that Thread, I screwed up and called the ET (External Tank) An External Tank Booster. I was promptly corrected and I fixed it.

Anyway, that led to further speculation on my part regarding the ET, which is Manufactured by Michoud, a Lockheed Martin Company. http://www.lockheedmartin.com/michoud/et/et_index.html

Anyway the ET used on this mission was an older model, called a LWT. The Newer ones started flying in 1998, and are 7500 Pounds Lighter and are designated SLWT. (The SLWT's weigh in 7500 lbs lighter than LWT's and 17,500 lbs. from the original.)

You can see the designation numbers here from Michouds website: http://www.lockheedmartin.com/michoud/et/shuttle_flight_info.pdf

Here is the breakdown of ET's according to missions flown.

STS-107 ET-93

STS-113 ET-113

STS-112 ET-115

STS-111 ET-113

STS-110 ET-114

STS-109 ET-112

STS-108 ET-111

STS-105 ET-110

STS-104 ET-109

And there are 8 other shuttle missions that used higher ET Numbers. You have to go back to STS-99, ET-92 for a prior flight which was launched on February 1, 2000.

Here is why this may be relevent. In the fs thread, we talked about the sprayed on insulation, and I was theorizing about it when thinking this ET was a newer, 7500 Pond Lighter SLWT.

I was wrong. But That is what NASA said in its Press Kit for this flight, which you can read here: http://www.shuttlepresskit.com/STS-107

On Page 18, it says: "External Tank ET93-A Super Light Weight Tank"

On Page 142, The Press Kit describes SLWT and not LWT.

So what did I do.

I emailed Michoud, a contractor who makes the ET's, and asked them.

They Replied back to me by email with this: "ET-93 was a LWT. It was delivered to NASA Nov. 2, 2000"

Except they spelled delivered wrong, and I corrected that.

I will not disclose the names of people I corresponded with, so Don't ask.

The Info matches the delivery dates of 11/2/2000, and the on-dock date of 12/20/2000.

I also have sent emails to NASA to inquire about this, along with my condolences.

Here are my questions.

1) Is the reported weights in the Shuttle Press Kit correct, or 7500 Pound too light, which is the difference in weight between the LWT and the SLWT.

2) Will the Insulation sprayed on the ET degrade over a period of 2 years such that it will break off on Launch. (Which it appears has happened)

3) Why did they even use a LWT, since the newer SLWT have been used since 1998.

4) If the insulation did not fall off the ET, It would not have damaged the Wing, hence potentially no disaster.

Folks, I am absolutely serious about this and have spent all morning researching this.

Here is what The news is currently reporting:

"The report said that a foam insulation patch about 7 inches by 30 inches in size popped off the fuel tank about 80 seconds after Columbia had left its launch pad, Readdy said. NASA engineers spotted the peeling insulation on high-speed cameras that recorded Columbia's launch."

That lead to other comments in that thread: Well, Ron Dittemore of NASA just said on the news conference, he is speculating the ET as the main cause.

Flame me all you want.

I know my theory is sound.

He also stated they were comparing debris from STS-112. STS-112 had an ET number of ET-115, delivered 9/26/01, On-dock 12/19/01.

If the ET from STS-112 is a SLWT, He was trying to compare two different tanks. The press kit from STS-112 also says it was a SLWT.

The ET-93 is a year older.

These are valid questions.

One more note. I have every right to speculate as does NASA. It was an accident, yes, but there is something called accountability, and I I have a theory, so what.

Ron Dittemore basically said in the Press Conference right now he considers the ET the cause as well.

He also just said they had had debris fall from the Et on STS-50. That launched on June 25th, 1992, and had ET-50, delivered on 10/31/88, and on-dock on 1/27/1992.

So it sat for over 3 years, before use.

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And in this thread: http://www.flightsimnetwork.com/dcforum/DCForumID2/4703.html

I said: Well,

The evidence is forthcoming.

Engineers did speculate a large gash had occured, and their memo was dismissed for reasons unknown.

I'm sorry. They knew or should have known if the engineer group last Thursday concluded it was a problem, they should have told the crew.

If they didn't tell the crew, many heads will roll, and that was wrong. They had 2 days to inform them. I hope it turns out they did tell them.

That Shuttle Commander is exactly that. Pilot in Command. He had a right to know and NASA has let us down again, IMHO.

Do Accidents happen. Yes. But when the engineers acknowledge a problem in an investigation they were charged with carrying out as is this case, whoever stopped that memo or refuted it has some responsibility, IMHO. It should have been investigated, and the landing postponed. They have postponed landings before, and they do have contingent procedures for that as well.

The engineers should be commended for writing the memo.

Next up, get rid of that Insulation, or find a way to reduce or eliminate that ice, and then we can fly again.

It wasn't the design of the shuttle, IMHO. It was a defect in design on the External Tank (ET) that I feel is complicit at this point.

EDIT: I was wrong, I called the ET The External Main Booster, which Ned pointed out to me. Thanks Ned. It is The External Tank

Here is the link for the ET http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/et.html End Edit:

I saw an astronaut on FOX showing how easily those tiles could be chipped away once the perimeter has been breached. It chips away quite easily.

Furthermore, that damage may have a causal effect in the induced drag that NASA has acknowledged on the left wing. This may have forced the Shuttle into a path not conducent to a proper landing trajectory which may also have contributed.

IMHO, the pieces are already falling into place, and while other events may turn up something different, I feel my and others theories similar to mine are sound and logical.

********************* And: Hi Josh,

Someone made a decision that was wrong, IMHO.

I firmly believe if we had to, we could have went and got them.

Look at the miracle of Apollo 13, and what they did to bring those heroes home.

I have confidence in the program even after this event. Someone dropped the ball here. The engineers felt differently than you stated, and that will be released soon enough.

As to the External Tank ET, I have corrected that in the post above. Thanks.

The current tank system has been used since STS-91 in 1998. The Liquid Hydrogen Tank and The Liquid Oxygen Tank are made of Aluminum Lithium, which according to NASA is 30% Stronger and 5% less dense than the prior metal alloy.

I am going to do some more research on the ET and see what the MFG says about the sprayed on insulation compared to the prior ET. The new ET is 7500 pounds lighter and thus allows heavier payloads to be delivered to the ISS. I would be interested to see how the Ice formed is either less or more in similar weather conditions.

Your point about Humidity is valid. Maybe we should look at another location for launches. Maybe Edwards would be better, who knows. Good Question though, as I have not looked at that yet.

You Said: "there weren't contingencies to rescue the crew on orbit. There was nothing that could be done."

I disagree. They saved Apollo 13's astronauts. I think if we had to retrive in orbit, someone would have designed a plan. Would it have worked. Who Knows.

But the important thing is that all of these questions, yours, mine and others need to be asked.

And about the Crew knowing.

Guess who has the decisions on all of the Abort Contingencies currently in place. Not The Ground.

It is the Flight Crew that determines the abort procedure carried out once launched. They should have been told. Period.

As to the Insulation, I did say: "Next up, get rid of that Insulation, or find a way to reduce or eliminate that ice, and then we can fly again."

That is still valid. If they find a way to eliminate that Ice, or that Insulation from the outside of the ET, there would not have been contact with the shuttle wing. That is what I should have said above.

The only thing I can think of right now, is the Double Hull Theory currently used on Oil Tankers.

If the ET Had a double shell with the insulation sprayed on the inner shell and then the outer shell may be protected from the ice. It is a thought. The question is, how can we eliminate the sprayed on insulation. Well, how about moving it to the inside shell. Just an Idea.

******************************** You Said: "-This ET was not one of the new Super Lightweight tanks, it was one of the last two Lightweight tanks (that have been flown since very early in the STS program)."

Please cite your official source on that, as mine states that it was a SLWT. And then I will post Mine.

The Weldalite on the ET is less than a Half Inch Thick. Yes they are on version #3, which has saved a total of 17,500 pounds from the original.

The ET-93 Was delivered by the MFG on 11/2/2000 and on dock, 12/20/2000.

You may be right about it not being a SLWT, but I do show differently.

The MFG says that ET-96 was the first SLWT Jettisoned form the Shuttle.

I just shot off an email to an official source, so I'll let you know what I get back.

And: It was a LWT.

I just got an email back from Michoud.

"ET-93 was a LWT. It was delivered to NASA Nov. 2, 2000."

I do wonder why they used an older model since they have been flying the SLWT's since 1998. Seems kind of Odd.

I got my Info from a NASA Press Kit, Page 142, which was obviously wrong, and on Page 18 where it states:

"External Tank ET93-A Super Light Weight Tank"

NASA has some more explaining to do. That is a major error in my book. Did they get the weights wrong, or is this just a Grammattical Error?

That would be a 7500 Pound Difference in Weight.

But I trust it was most likely a typo.

We'll see.

Here is a Link for the Press Kit last updated 12/8/2002, Page 9: http://www.shuttlepresskit.com/STS-107/

I also sent a request to NASA for addtional Clarification on the Press Kit Discrepancies.

And: Ok the closest comparison would have to be with STS-50, which was also Columbia, and took off in June of 1992.

It had ET-50 delivered on 10/31/1988 and on-dock 1/27/1992.

Same Shuttle, although it does not state whether it used a LWT, it most likely did.

Columbia last flew in March of 2002 (STS-109) with a SLWT, menaing it had 7500 lbs. less of an External Tank, thus allowing more payload. That mission was a Hubble Maintenance Mission.

The comparison of STS-112 Atlantis (The debris comparison by NASA) Should not have been done as this was a different lighter shuttle, and a Lighter External tank. (A newer SLWT).

Can you compare a tire going flat on a Michelin to a Goodyear. Two totally different designs.

2 different shuttles 2 different External Tanks

Now, it still has to be ascertained whether the sprayed on insulation process is different, and Michoud says it is, and different amounts are sprayed on the tanks at a different thickness.

Folks, all I am saying as this. NASA has been very forthcoming, but come to your own conclusions as well.

Their press conferences have already made mistakes in accuracy, and the Press is giving them passes, maybe because they don't realize this.

Their Press kit is wrong, and the press may be relying on some of that info as well.

********************** In This Thread:

Braun over at Avsim posted this: http://ftp.avsim.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=1422&forum=DCForumID6

From the NASA Page:

During the STS-87 mission, there was a change made on the external tank. Because of NASA's goal to use environmentally friendly roducts, a new method of "foaming" the external tank had been used for this mission and the STS-86 mission. It is suspected that large amounts of foam separated from the external tank and impacted the orbiter. This caused significant damage to the protective tiles of the orbiter. Foam cause damage to a ceramic tile?! That seems unlikely, however, when that foam is combined with a flight velocity between speeds of MACH two to MACH four, it becomes a projectile with incredible damage potential. The big question? At what phase of the flight did it happen and what changes need to be made to correct this for future missions? I will explain the entire process.

http://quest.arc.nasa.gov/space/updates/sto32.html

bt

Braun Tacon

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I added: Good Find,

Another example of why we need to keep asking questions.

basically what I have learned is they spray a different thickness on different parts of the ET's.

STS-87 had an ET-89 which Had a delivery date of 6/26/1997 and an on-dock date of 7/15/1997.

STS-87 flew on 11/19/1997, which was alos Columbia and it sustained extensive tile damage during launch according to Michoud.

***************************

Also: MOST IMPORTANT Discovery Yet. Someone pointed it out to me. This NASA Engineer Knew.

Same Article: http://quest.arc.nasa.gov/space/updates/sto32.html

Whoaa..

Look at what this guy said: Greg Katnik 12/1997 (Engineer at Kennedy Space Center) " The tiles do a fantastic job of repelling heat, however they are very fragile and susceptible to impact damage."

Further down, the questions that he asked:

Now the big question -- why? The evidence of this conclusion has now been forwarded to Marshall Space Flight Center (MSFC) because this is the design center for the external tank. MSFC will pursue the cause of damage. Here are some descriptions of some of the possible causes:

POSSIBILITY 1 The primer that bonds the tank foam to the metal sub-stream was defective and did not set properly. This was eliminated as a cause because the photography indicated that the areas of foam loss (divots) did not protrude all the way down to the primer.

POSSIBILITY 2 The aerodynamics of the roll to "heads up." The STS-87

mission was the first time this maneuver had ever been completed.

POSSIBILITY 3 The STS-86 mission revealed a similar damage pattern but to a much lesser degree than STS-87. The STS-86 tile damage was accepted ruled as an unexplained anomaly because it was a night launch and did not provide the opportunity for the photographic evidence the STS-87 mission did. A review of the records of the STS-86 records revealed that a change to the type of foam was used on the external tank. This event is significant because the pattern of damage on this flight was similar to STS-87 but to a much lesser degree. The reason for the change in the type of foam is due to the desire of NASA to use "environmentally friendly" materials in the space program. Freon was used in the production of the previous foam. This method was eliminated in favor of foam that did not require freon for its production. MSFC is investigating the consideration that some characteristics of the new foam may not be known for the ascent environment.

POSSIBILITY 4 Another consideration is cryogenic loading, specifically hydrogen (-423 degrees Fahrenheit) and oxygen (-297 degrees Fahrenheit). These extreme temperatures cause the external tank to shrink up to six (6) linear inches while it is on the pad prior to launch. Even though this may not seem much when compared to the circumference of the external tank, six inches of shrinkage is significant.

This is where the investigation stands at this point in time. As you can imagine, this investigative process has required many hours and the skills of many men and women dedicated to the safety of the shuttle program. The key point I want to emphasize is the PROCESS OF INVESTIGATION, which is coordinated amongst many people and considers all possibilities. This investigation has used photography, telemetry, radar coverage during the launch, aerodynamic modeling, laboratory analysis and many more technical areas of expertise.

As this investigation continues, I am very comfortable that the questions will be answered and the solutions applied. In fact, some of the solutions are already in progress. At present the foam on the sides of the tank is being sanded down to the nominal minimum thickness. This removes the outer surface, which is tougher than the foam core, and lessens the amount of foam that can separate and hit the orbiter.

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Well, It seems they were aware of this problem, huh?

Good for NASA, but it didn't work, IMHO, whatever changes they made still continued to occurr.

We are darn lucky that other shuttles have not crashed before this. This is a very serious issue.

************************

I am convinced that Michoud's name will be learned as well as Martin Marrietta was in relation to Challenger.

The External Tank was the Cause, and the tiles were the effect.

Fix the ET's and we can get back where we belong. I have taken an enormous amount of grief over this, but that is ok. I'm used to it.

Regards, Joe

LINKS:

Michoud Shuttle Flight ET Info:

http://www.lockheedmartin.com/michoud/et/shuttle_flight_info.pdf

External Tank Info:

http://www.lockheedmartin.com/michoud/et/description.htm

STS-107 Shuttle Press Kit

http://www.shuttlepresskit.com/STS-107

Thread Links:

BBC Shuttle News Video: http://www.flightsimnetwork.com/dcforum/DCForumID2/4711.html

Shuttle Damage:

http://www.flightsimnetwork.com/dcforum/DCForumID2/4703.html

NASA Discrepancies you won't see on CNN

http://www.flightsimnetwork.com/dcforum/DCForumID2/4712.html

Nasa Avsim:

http://ftp.avsim.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=1420&forum=DCForumID6

Other Tile Damage: Nasa Knew:

http://ftp.avsim.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=1422&forum=DCForumID6

My Memorial to Columbia:

http://http://home.attbi.com/~Sonar5/Shuttle/memorial-sts-107.jpg

[GovernmentShrinker]

ping

[GovernmentShrinker]

2) Will the Insulation sprayed on the ET degrade over a period of 2 years such that it will break off on Launch. (Which it appears has happened)

Have you established when and where this insulation is foamed on? I.e., does the fact that the tank was shipped to NASA in 2000 actually establish that the foam had been sitting on it all this time?

[Sonar5]

You Said:
'Have you established when and where this insulation is foamed on? I.e., does the fact that the tank was shipped to NASA in 2000 actually establish that the foam had been sitting on it all this time?"


Good Question. It is my understanding it is applied at the manufacturing facility in Louisiana. I have come across nothing that conflicts with that.

Regards,
Joe

[GovernmentShrinker]

Next question (since nobody else seems to be peppering you with questions):

Can you create a table starting with STS-86 (first mission where the new "environmentally friendly" foam was used) which shows: 1) tank class (LWT/SLWT), 2) foam type (old/new), 3) degree of tile damage (e.g. STS-87 & STS 107 "severe" (at least presumed so for STS-107)/"moderate"/"negligible"), and 4) possible other contributing factors to moderate or severe tile damage (e.g. STS-87 was first mission to perform the "roll to heads up" maneuver). I'm interested in how many missions have had the combination of new foam and old LWT tank.

[Sonar5]

Ok, I'm working on it.

[SirAllen]

There is no such thing as a tile repair kit. So even if they had the "jetpacks" what good would have it done? The only thing that'd come from it is "we're going to die." And each of the 30,000 tiles on the shuttle are uniquely shaped, so unless they stocked all 30,000 of them in the shuttle bay which wouldn't leave them enough room to even get out on that spacewalk, nothing could have even been done beforehand. Not to mention the impossibility of gluing them back on in the void of space with huge temperature variances and no atmosphere.

[GovernmentShrinker]

Good. Remember, no rest for the weary. All work and no play makes Sonar5 a Freeper Extraordinaire :)

BTW, somebody ought to watch the next NASA press conference, and see if some smarty-pants reporter asks about the tank type discrepancy, as if s/he was the first to notice it.

[GovernmentShrinker]

Good. Remember, no rest for the weary. All work and no play makes Sonar5 a Freeper Extraordinaire :)

BTW, somebody ought to watch the next NASA press conference, and see if some smarty-pants reporter asks about the tank type discrepancy, as if s/he was the first to notice it.

[Sonar5]

Valid Points Sir Allen.

The External tank is the Cause, and the Tile damage is the effect, IMHO.

Fix the External Tank so it does not lose debris, and we can get back to space.

The Shuttle is a sound design, IMHO.

Regards,
Joe

[Cold Heat]

Yup sonar, I found all this stuff last night, but I did not need to look hard.

The fact that the heavier tank was used is that it fit into the weight allowances. According to the initial NASA briefing after the accident, it was one of only two left in inventory. They have been using the ulta light sue to the heavy payloads going to the ISS. The heavier tank fit the profile because they had removed a great deal of weight from the Columbia during re-fit.

Unfortunately they did not have any issues at the time with the insulation because they assumed the problem was fixed. They had sanded down certain areas of the insulation and done a number of other things to mitigate the insuation loss problem.

Apparently it was not enough.

BTW, Michoud is my old stomping grounds. It is pronouced "Meeshooo".

[expatpat]

What on earth is this rambling about. Can you give a succinct summary of your "theory", so we can understand what you are talking about? (and what has you single-engine license got to do with it?)

[Cold Heat]

Fix the External Tank so it does not lose debris, and we can get back to space

Unfortunately, my take on this is a bit more conservative.

I believe that the insulation strike did in fact contribute to the loss of Columbia, but it was not the sole cause.

The investigation should reveal this and Iam content to be patient.

What I am saying, is that if another shuttle, not Columbia had made this flight with the same tank, the results may very well have been different.

There is more to this IMHO!

[GovernmentShrinker]

Old model tank used on this mission. Hadn't been used for a long time (more recent missions used newer, lighter model). NASA current press kit misidentifies this mission's tank as being the newer model. Sonar5's direct communication with someone at Michoud confirmed it was actually the older model.

[Cold Heat]

He found the data that the tank was a old model with previous problems and connected the dots.

The only thing that I disagree with is the inference that NASA did not state which tank was used. Fortunately I heard them admit this during the initial briefing. The engineer stated that the older heavier tank was used. "One of two left in inventory", he said.

On the NASA site is the story of STS-87 and 86 which had insulation problems with this same tank in 1997.

[ASOC]

Uh, Dude
SLWT is used for ISS missions, the LWT is used for non-ISS misions. The difference in weight is a big deal for final orbit. Non-ISS mission = use old tank from stock.

This was covered in some depth in a press conference BTW.

Sorry you had to waste your morning.

Have fun.

[Denver Ditdat]

Look at the miracle of Apollo 13, and what they did to bring those heroes home.

Miracle is exactly right. Had the cryo tank explosion occured at almost any other time in the mission, Lovell, Haise, and Swigert would be dead. Earlier in the misison and there would not have been enough consumables. Slow death. Later, and the LM "lifeboat" would be left behind on the lunar surface. Quick death. Fatal either way, and all the wishing, hoping, and speculating in the world could do nothing about it.

As regrettable as it is, life isn't a Star Trek movie plot in which the heroes always narrowly escape and fatalities are suffered only by the expendable "no name" red shirts.

Sorry. I wish it were otherwise, too, but this time we fell outside the narrow margins of skill and good fortune.

[Cold Heat]

As a addendum to the above, I must say that the tank problem had been mitigated after 1997, and they honestly thought they had fixed it.

[GovernmentShrinker]

But if the old tank had problems associated with it other than greater weight, it wouldn't be a great idea to use it on any mission. It appears that this MAY be the case.

[Sonar5]

From the press conference Right NOW.

The guy on the press conference right now just said it is only the third occurence of debris hitting it.

Incorrect. At least Five that I am aware of.

STS-50
STS-86
STS-87
STS-112
STS-107

That is at least 5 debris reports from official sources in my links.

[Cold Heat]

They performed a number of mods on the tank and it was deemed safe and had not repeated the events of the past.

This tank unfortunately did. I cannot bring myself to be critical of the decision to use it.

In retrospect, sure! It was a bad idea, but who could have contemplated the accident and who could have made the decision to scrap this multi-million dollar hardware with no evidence except old historical records that have no relationship to the modified and repaired tank.

It is possible that time had caused the adhesive to fail and the shelf life of the tank was mis-interpreted.

Bear in mind that the insulation loss was really minimal compared to the initial difficulties. Bear in mind that this loose insulation had to act in a very peculiar way to cause the required damage, (assuming it is the cause) and that luck, fate and something else likely played a part in this.