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

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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.

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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.

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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

[XBob]

16 - "For what it is worth, I estimate that the BLOCK of ICE, clearly visible as white BEFORE it struck the left wing,"

Seems like this should be pretty easy to determine, ice or insulation (it sure looked like ice to me) by simple spectrographic analysis of the colors.

[XBob]

Excellent, and hard work Sonar5. Thankyou very much. You dug out and organized and quantified some very good info, and that is very hard to do with all the variables. 107 lashes with a wet noodle for each of your detractors.

23 - When I worked at KSC 88-91, the ET's came from the factory, by barge and were foamed at the factory.

Minor repairs for damage were done at KSC.

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Guys, Now, for some observations/points which may help or hinder, but please add to your already brimming thinking caps.

1. Sometime earlier this morning, in a daze between awake and dreaming, I thought I heard a spokesman (from somewhere, where I don't know) say that this tank had different insulation, which had a different gas component, and because of that, the gas expanded when losing atmospheric pressure, causing the foam cells to explode, like popcorn.

2. Sonar5, now this got me to thinking, and combined with your point about ages of the tanks, caused me to think about another serious shuttle problem we had during those years, and that was all the trouble we had water proofing the tiles on the shuttle, so they were protected from the rain/moisture.

3. KSC is located on the ocean, and NORMAL humidity is 95%, or higher. Moisture/humidity permeates everything, it's normal. The external tanks are stored in the Verticle Assembly Building, which is air conditioned, but each time one of the giant 500 foot tall doors is opened, it loses air conditioning. In fact, the humidity inside the building gets so great that it has been known to rain, inside the building. (no joke - guiness book of records I believe).

4. I have no idea if it has anything to do with the problem, but I would assume that gradually, even the driest of foam coatings would be permeated with moisture, just sitting there in storage. And then coupled with the humidity, there may be an aging/deterioration factor.

5. I pose the question - is there a relationship, between the time the tank sits in storage and the propensity of the insulation to perhaps make like popcorn and peel off?

[Atchafalaya]

It was also calculated that the speed of the foam impacting the shuttle was 61 mph (remember it was going as fast as everything else when it broke off); not at some hypervelocity as some would imply.

[GovernmentShrinker]

Do you think there may be a link between long storage time of the tank and propensity of the foam to break off at launch?

[Atchafalaya]

Dittmore said that the lwt used was one of two in the inventory on site at Canerveral.

[Al B.]

Dittmore said that the lwt used was one of two in the inventory on site at Canerveral.

For the record, I also heard him say that. He clearly said it was a LWT.

[GovernmentShrinker]

Yes, ET-94 hasn't flown yet (maybe it never will).

[jackbill]

Frankly, I gave up reading about a third of the way through. NASA said, two or more days ago, that the ET was the second to last LWT in their inventory. The SLWTs have been used for Shuttles going to the ISS, since it's orbit is higher than non-ISS Shuttle missions.

Secondly, this morning's NY Times hinted that the problem of peeling insulation from the ET started when - in order to be environmentally friendly - NASA stopped using freon in the production of the insulation.

[SirAllen]

Well, then we agree to disagree.

The facts are that it would take at least a month at the very earliest to get another shuttle up there - and that would be putting that shuttle at great risk. Soyuz was also out of the question. The fact remains that if Commander Husband was faced with a 100% certainty of death by remaining in orbit, and an unknown certainty of reentry, reentry would still have been the only choice. They may have remained in orbit 4 more days until their life support started running low, and then gave reentry a try but either way their death warrants were signed 81 seconds into the launch.

Sure, they would have gotten to say goodbye and we would have had a world wide drama and horror played out over multiple days that would have been much more painful. I don't know, if I was faced with the choice of knowing 4 days before I die that I was going to die, or not know, I'd choose not know. Also I think you assume too much that the families would like to have had that extra time. Again, if it was me I wouldn't have wanted that extra time. I couldn't handle the drama and emotion, it'd just make the inevitable worse.

[tubebender]

It would probaby not have broken your windshield, but might have cracked it and would have blown into thousands of fragments and dust.IMHO

If it wouldn't have broken a windshield how did it damage the tiles?

[GovernmentShrinker]

Those tiles are incredibly fragile.

[Ravenstar]

Apollo 13 Did not have a heat shield problem. We could have delayed maybe 5 days before they ran out of consumables, oxygen for example, they could not have changed orbital plane and gone to station because they did not have sufficient engine or fuel to do so. The beginning, I have not and wont read all of it right now, theory or suppositions until you get to your Apollo 13 comment is factual and well grounded and you allow for things to change in light of new facts. Keep going and you will get there.

Ravenstar

[Ravenstar]

You are correct on this point SirAllen at this time this is the case.

Ravenstar

[Cold Heat]

If it wouldn't have broken a windshield how did it damage the tiles?

That is what NASA is wondering about. They believed, as do I that the damage should not have been so severe to total the shuttle. It has landed safely before with over 300 damaged tiles.

Some fluke of nature or as yet unknown sequence of events occurred, or the object did something while it was behind the wing that we could not see.

[XBob]

5-"I'm sorry, but stating that you have spent "all morning" researching this topic (given its complexities) doesn't exactly inspire confidence.

---

Well, Sonar5 certainly inspires a lot more than just confidence, especially when compared to a John from Manhattan.

[XBob]

Wow, thanks for clearing everything up. Can you create a winning strategy for the upcoming war...and perhaps design a fuel-cell vehicle before you leave work today?

No hollywood red, that would take Sonar5 at least a day for each of those problems.

Ever consider going into public relations? you give such fantastic compliments.

[Sonar5]

Two days Max, is all I need for those problems. ;-)

But I'm busy right now,

Regards,
Joe

[Libertina]

Sonar you have really worked diligently on researching this... I am reading and trying to digest it now.

[aquawrench]

"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."

Are you saying that when the foam came off, it was moving at zero mph? There had to be ice involved to mar the tiles so badly.

[Sonar5]

Hi,

Keep your eye on the ball here.

The debris was the cause, the tile damage was the effect.

Eliminate the cause (debris), no more tile problems. I still feel the tiles and the Shuttle are sound.

My concerns are the External Tanks.

If you saw any of the demonstrations with the tiles, you can do damage with a fingernail.

I mentioned a double-hull theory yesterday on another board. But what if it was, and then the insulation was sprayed on the inner hull, leaving the outer hull only weldelite, (The Alloy). If the Inner hull is very thin, this might be a solution. The ET right now is only a half inch thick.

It's just a thought, so feel free to bash me on its merits. And yes, of course weight is a consideration, but so should be lives.

Regards,
Joe