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Michoud External Tanks May Hold Clue About Columbia Accident
Nasa, Michoud ^ | 2/4/2003 | Joseph Ranos

Posted on 02/04/2003 10:13:05 AM PST by 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:


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.


ET = External Tank

LWT = Light Weight Tank

SLWT - Super Light Weight Tank


I was involved in a thread on flightsim here:

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.

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:

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:

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.


And in this thread:

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 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:

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:

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.


Braun Tacon


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:


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.


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


Michoud Shuttle Flight ET Info:

External Tank Info:

STS-107 Shuttle Press Kit

Thread Links:

BBC Shuttle News Video:

Shuttle Damage:

NASA Discrepancies you won't see on CNN

Nasa Avsim:

Other Tile Damage: Nasa Knew:

My Memorial to Columbia:


TOPICS: Breaking News; Government; News/Current Events; US: Florida; US: Illinois; US: Texas
KEYWORDS: columbia; michoud; nasa; shuttle; space
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1 posted on 02/04/2003 10:13:06 AM PST by Sonar5
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To: Sonar5
bookmark bump
2 posted on 02/04/2003 10:25:36 AM PST by tophat9000
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To: Sonar5
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?
3 posted on 02/04/2003 10:25:54 AM PST by BurbankKarl
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To: Sonar5
I agree the external tank is the most likely suspect. If NASA screwed up anywhere it was the use of an older model that they had previously had a problem with, last October if I'm not mistaken.

However, not using all their resources to inspect the damage to the wing, and suppressing any kind of engineering analysis of the potential damage, was NOT wrong on the part of NASA. There was absolutely nothing they could do, no matter what the Monday morning quarterbacks are saying. If they discovered a serious problem on the wing beforehand it would have made this horrible situation 10 times worse than it already is. Imagine this scenario, uh crew, the shuttle is severely damaged and will not make it back on reentry, you only have a week of life support left, there's no way we can get to you, you can either die from lack of life support or die reentering. A horrendous situation. It was the right call, because in this situation it was definitely better to not know.

4 posted on 02/04/2003 10:29:56 AM PST by SirAllen
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To: Sonar5
Sonar5 states: I am absolutely serious about this and have spent all morning researching this.

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

5 posted on 02/04/2003 10:32:50 AM PST by John from Manhattan
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To: Sonar5
Speaking entirely as a laymen, some things are obvious. I agree with you that for the future they need to make changes to solve the fuel tank insulation issue.

Having said that, I also believe everybody is aware that the heat shielding system on the shuttle is fragile and may be the only thing that separates successful reentries from disasters. In regard to inspecting the tiles while in space, I gotta believe there is a way to do this, even though there may not be a realistic way of repairing them.

If Saturday morning, the newscasts had instead reported that we had an emergency in space due to damaged tiles and that NASA was exploring ways to rescue the crew............... I just have to believe that we can find a way in space to inspect this system and make contingencies to get the crews home.

6 posted on 02/04/2003 10:33:35 AM PST by umgud
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To: John from Manhattan
John, That really meant about 8 hours, and another 7-8 hours since then.
7 posted on 02/04/2003 10:35:07 AM PST by Sonar5
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Comment #8 Removed by Moderator

To: BurbankKarl
How about something constructive to say instead.

This is relevent information, if you honestly take the time to read through the links. Then you can draw your own conclusions.

IMHO, It will take someone more than 2 hours just to go through the links verifying what I wrote.

Then, I will appreciate your views on it.

Thanks for responding though.


9 posted on 02/04/2003 10:42:29 AM PST by Sonar5
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To: SirAllen
Where I question NASA's planning on this trip was their decision to not take any jetpacks or other equipment along that would allow the astronauts to inspect or work on the exterior of the shuttle. Given the criticality of the tiles, and their proven tendency to occasionally fall off, I would think that you would always want to maintain the ability for inflight repairs to the exterior.
10 posted on 02/04/2003 10:46:01 AM PST by Avid Coug
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To: John from Manhattan
Hi John,

Further clarifcation. I began this Monday Morning. That reference is a quote from a discussion I was having on another board while compiling different data, even from other people as well.

I can see how the reference taken out of context can be confusing. So I apologize for phrasing it that way. That statement was made yesterday late afternoon.

Total Time approximately 12-15 hours.

11 posted on 02/04/2003 10:49:07 AM PST by Sonar5
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To: SirAllen
Unfortunately for those who want to tie up an objective matter subjectively, you're probably very close to what transpired. If the variables of the situation were in fact constants that could not have been corrected or changed, what good would it have been to play out a week of sheer madness for all involved.

Extreme moral and ethical situation? Regretfully yes, but life plays a fierce hand with those who dare to challenge the boundaries of greatness.
12 posted on 02/04/2003 11:03:06 AM PST by GalaxieFiveHundred
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To: Sonar5
Why even bother with this? The BBers will just come in here, tell you that you don't have all the facts, and insist that you tolerate the level of incompetence that presently exists.

(Nice job BTW)

13 posted on 02/04/2003 11:05:03 AM PST by BureaucratusMaximus (if we're not going to act like a constitutional republic...lets be the best empire we can be...)
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To: Sonar5
Awesome work. But, no rest for the weary :)

Can you put dates on that list of mission numbers/tank numbers, and explain the tank numbers? ET-113 appears to have been used twice (but none of the other tank numbers on your list were) -- is this a model number, or an item serial number? If the latter, are these things reusable, or not?
14 posted on 02/04/2003 11:14:17 AM PST by GovernmentShrinker
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To: Sonar5; All
or find a way to reduce or eliminate that ice, and then we can fly again

For what it is worth, I estimate that the BLOCK of ICE, clearly visible as white BEFORE it struck the left wing, as weighing AT LEAST 20 pounds, and more probably 30 pounds, and storing much energy in the form of compression.

The white cloud after impact is NOT insulation, but something MUCH WORSE...FLASH Sublimation of ice crystals with a SHOCK WAVE directed into the interior of the wing.

15 posted on 02/04/2003 11:21:05 AM PST by Lael
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To: Sonar5; All
or find a way to reduce or eliminate that ice, and then we can fly again

For what it is worth, I estimate that the BLOCK of ICE, clearly visible as white BEFORE it struck the left wing, as weighing AT LEAST 20 pounds, and more probably 30 pounds, and storing much energy in the form of compression.

The white cloud after impact is NOT insulation, but something MUCH WORSE...FLASH Sublimation of ice crystals with a SHOCK WAVE directed into the interior of the wing.

16 posted on 02/04/2003 11:21:06 AM PST by Lael
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To: Sonar5
>>... Why did they even use a LWT, since the newer SLWT have been used since 1998...<<<

The orbiters,SSME's, SRB's and ET all had to have major performance/weight upgrades in order to reach the inclination of the ISS

In the case of the ET's, they were made lighter.

Columbia had not been modified and was too heavy for a mission to the ISS.

I don't know if the LWT was able to be used on an ISS mission, but I can guess that NASA did not choose to use the SLWT for this one because it was not an ISS mission.

Just a guess.

17 posted on 02/04/2003 11:25:25 AM PST by FReepaholic
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To: Ravenstar; Vinomori; Excuse_My_Bellicosity
18 posted on 02/04/2003 11:45:55 AM PST by GovernmentShrinker
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To: Sonar5
Good work.

America needs to exchange our culture of vilifying whistleblowers with a culture of lionizing whistleblowers.

While the astronauts knew the risks when they enlisted, there is no need to send them into Somalia without bullets.

19 posted on 02/04/2003 11:49:09 AM PST by Nephi (Extremism in the defense of liberty is no vice. Moderation in the pursuit of justice is no virtue.)
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To: GovernmentShrinker

Thanks for catching that no one else has, not even me.

ET Stands for External Tank Number, so Yes the Mfg. Michoud numbers each one different. They are not reusable and burn up in the atmosphere on re-entry usually over an Ocean.

Whereas STS stands for the Mission Number.

STS-113 Had an ET of 116. The Et's are assigned a mission so they will not always be in chronological order.

STS-107 ET-93

STS-113 ET-116

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

Mission dates are available here in PDF Format. Start at the bottom and work backwards, Its quicker.

Michoud Shuttle Flight ET Info:

Michoud has the best info as the Shuttle Press Kit info is wrong, as was confirmed by my emails to Michoud.

Michoud lists ET dates and Missions in the above file.


20 posted on 02/04/2003 11:51:00 AM PST by Sonar5
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