Observation on TPS damage on Orbiter

NASA photos | 2-3-03 | BoneMccoy

[r9etb]

Then there is the video the two young men took as it passed over Nevada. It clearly shows something comming off. They even comment on it on the tape. What I have no idea is, is that he same pice that the fellow in California saw and photographed, or another piece.

I'm guessing that it was a different piece. The stuff falling off early would have been primarily tiles, I think, and they're so light that they'd fall behind quickly.

California to Nevada is probably about a minute's flight....

[_Jim]

I'm taking it to be ice - that hit the leading edge of the wing in the LESS (Leading Edge Structural Subsystem) area and perhaps a tile or so as well ... damage to the LESS can also result in catastrophic failure of the shuttle on reentry due to plasma (hot gases) making their way in to attack the wing spars (constructed of aluminum) ...

[bonesmccoy]

The WFAA home video from Arizona was interesting.

The object that separated from the orbiter was sufficiently large to create a large glowing plume.

That is not a tile. Tiles wouldn't create such a plume.

It's structure.

[Jim Noble]

>> Even if they had done an EVA to evaluate the wing damage, there is no way they could have repaired the damage or rescued the crew (unless the next flight was rushed to the pad and risked to save the crew)<<

And, just like a decision to abort to Spain would not have been obviously correct, I bet that if they did an EVA the results would have been equivocal, not enough to risk the Atlantis crew.

I suspect the damage (if any were visible) was of a kind previously survived. There was an unexpected synergy between the location (near or on the gear door) and the damage which was not revealed until stress tested.

If there were a huge tile defect, so big that the reentry clearly had to be scrubbed, I think we would have seen burn-through and wing loss earlier.

What we saw instead was an initially subtle aerodynamic change which worsened throughout the terminal sequence in association with shedding of burning material (presumably tiles). When the stabilization program went beyond previously tested limits, the shuttle ceased to be aerodynamic and was pulverized in a second by the force of air at 12.5K mph.

I think vehicle loss was unexpected by the passengers. I don't know anything about it, but I suspect that wing loss or tail loss as some have speculated would have produced severe, severe buffeting and been reported to JSC by the crew.

I bet the shuttle turned or flipped in a second, and a second later it was gone.

Thanks, bones, for your fantastic work on this thread. I predicted on Saturday that we would have a very high quality failure analysis thread, but this has surpassed my expectations.

[Jim Noble]

>>It's structure<<

elevon?

[r9etb]

Since the space between the fuel tank and the shuttle is constricted, wouldn't this cause the air to rush through it at an accelerated rate? Would that cause any object that fell into that channel to propel at an increased rate than otherwise?

The Shuttle was supersonic at this point. It's difficult to say exactly what's going on in there, but I would think there's a lot of strange shock wave action going on in there, and turbulence as well. So the air is certainly rushing through the gap, but it's difficult to say what this would mean for a chunk of something.

[Jim Noble]

I think the really bad news is that a new Feynman will point out that this event was probable, and that it was assigned a low prob value because it hadn't happened yet.

I don't think the vehicle in its present form is usable.

[r9etb]

That is not a tile. Tiles wouldn't create such a plume. It's structure.

I tend to agree. IIRC, that particular piece also stayed fairly close to the Shuttle for quite a while, meaning it had a similar ballistic coefficient -- which implies it must have been fairly massive.

The obvious question then would be: what?

My first guess would be the left landing gear door.

[Jim Noble]

>>The obvious question then would be: what?<<<

What, and why didn't its loss increase turbulence to the point of a crew report?

[Jorge]

Observing Monday's news conference, Ron Dettemore's composure appeared to dramatically change when asked about the possibility of ice on the insulating foam, and how that would change estimates of damage to the tiles. His voice hardened and became loud as he appeared to obfuscate and hide behind "intelligent men assessed all possibilities and decided there was not a problem".

Sounds like he was kind of put on the defensive.

I'm willing to bet that the possibility of not just foam insulation coming off, but ice along with it is a possibility the NASA engineers could have easily overlooked in their analysis.

Common sense tells us that damage to left wing area is the cause of the left wing problems seen by ground control prior to the shuttle break-up.
My bet is NASA engineers already believe they screwed up.

[Jim Noble]

>>My bet is NASA engineers already believe they screwed up<<

It's the design that's screwed up.

[Lower55]

I wonder.....Did they check to see of that wing was heating up during ascent?

[bonesmccoy]

I do not believe the object in the Arizona home video is the elevon.

I agree with r9etb in http://www.freerepublic.com/focus/news/835531/posts?page=108#108.

The object may be the left landing gear door.

If the TPS tiles in the vicinity of the left main gear latch were damaged, the heating could melt the latch and the door could swing open.

On the other hand, I think there are indicator lights which alarm if the latch opens or the door is open.

NASA stated 48 hours ago that the orbiter was compensating for increased drag on the port side (which was inducing a roll). If the increased drag on the port side temporarily is reduced at the exact time the AZ video shows separation of the object in the video, then something was torn from the left wing over AZ.

If memory serves, the orbiter landing gear door is designed to drop open quickly in the event of failure of the gear door latch to decouple in the seconds prior to landing.

Plotting wing temperatures on a graphic image of the vehicle is easily possible using PC technology.

I'm sure JSC engineers are working the problem right now.

[mikegi]

The initial frames are a bit confusing to an untrained person. You can see multiple white objects in a few frames. However, the forward orbiter attachment is between the tumbling white object and the camera. It appears that the object slides between the forward ET-orbiter attachment posts.

Thanks for posting these excellent links. I've been stepping through the video and disagree with your conclusion that it was a single piece that appears split because of an obstruction. Here's what I see (frames identified by the second in the mpg):

0:00-0:04 - object appears, flies up the tank, hits it

0:05-0:06 - object bounces off and either splits in two or dislodges another object. Call the lower one A and upper one B.

0:07-0:08 - "A" passes between the wing and tank. "B" reaches the front edge of the wing

0:09:0:10 - "A" emerges from underneath the wing, apparently broken up into two pieces. "B" probably impacts the wing at this point.

0:11-0:14 - "B" emerges as a cloud underneath the wing and spreads out all the way to outside the solid rocket.

0:15-0:16 - two fairly solid pieces of "B" pass in front of the SRB and are illuminated by the fire it.

[steve86]

Does anyone have estimates of the Shuttle's:

1) "Indicated" Airspeed (i.e. taking #2 into account)

2) Density Altitude

3) Are these terms from low-altitude aviation meaningful in near-space?

[Cold Heat]

I've not seen any evidence of aft fuselage material.

Nor have I, but I do understand that some debris have been found in Arizona and possibly Nevada or California, but the info is sketchy.

If the debris is tiles, then the serial numbers may be intact and the exact location can be determined.

If they find part of the vertical stabilizer, that would change the equation. Wing drag would be replaced with stability and control issues I would think.

Too early to speculate until the data is available. I guess we all like a good mystery, but speculation is so often wrong. I see answers coming within weeks, not months.

[Jorge]

>>My bet is NASA engineers already believe they screwed up<

It's the design that's screwed up.

That would mean they screwed up twice.
On the design and on the analysis of the damage cause by the foam insulation striking the wing on lift off.

[bonesmccoy]

Jim,

Thank you for your highly complimentary statement.

Free Republic is a manifestation of our desire as Americans to learn, to build, and to improve ourselves and our nation. The team running this site has much to be protect and much to defend. They are to be congratulated.

Regarding the issue of an emergency EVA to evaluate the impact damage, the NASA shuttle program team and the JSC Mission Directors would have probably considered it. However, if they were told that the impact damage is likely minimal (and especially if the contractor supports the evaluation), the team is unlikely to consider an emergency EVA. Such EVAs were only contingent on specific conditions and I doubt that TPS evaluation is a condition.

In the event of any tile defect, the contractor should have the capability to do computer simulation of the reentry trajectory based upon the known condition of the TPS.

The impact of the ice chunk seen on the KSC PAO video archive is rather large. To be honest with you, within hours of the accident, Freepers had posted the image of the impact and began analysis. Initially, I doubted that the impact was sufficient to cause the accident. However, when the higher resolution KSC Ice Team film was produced, I was disappointed to find that the ice chunk was substantial in size.

The reason you did not see separation of the port wing earlier in flight was that the wing does not become a useful aerodynamic surface until the last few minutes of flight. The reality is that the wing's TPS appears to have been damaged by the impact (because I think the plume is composed of some silica dust from the TPS).

In order to evaluate the structural stability of the port wing, you would have to plot the structural stability of the wing against the loss of integrity due to heating and aerodynamic forces.

Essentially OV-102 was an Eagle flying with a broken left wing. Although the TPS damage did not terminate flight during launch or orbit, the damage was significant enough to compromise thermal control during reentry.

The shedding of material over California and Arizona is significant. The home video taken by the boys in Arizona is telling. Some orbiter structure was lost over Arizona but it is only conjecture to guess what it was. I'm sure that JSC knows. They should have enough telemetry to identify if wing spars, gear, or elements of the vehicle were being shed over Arizona. The transcript of the ATG transmissions should be telling.

With respect to the aerodynamic stability of the orbiter, you are probably correct.

Like in the accident during STS-51-L, the orbiter breaks up into many pieces as aerodynamic forces shear the vehicle. The vehicle's structures shreds in the force of the atmosphere. The major elements of the vehicle are torn apart (a wing, the crew module, the tail, an engine, thruster rockets, etc. separate). These elements at 200,000 feet are seen on the WFAA films as separate objects.

I agree that the vehicle disintegrated so fast that the crew never knew what hit them. They died instantly.

Rapid cabin decompression at 200,000 feet creates instant loss of consciousness. Only if oxygen was flowing would you see any potential for the human to regain consciousness at lower altitude. Because the crew module debris appears to be located in widely separated areas, I am fairly certain that the crew module did not emerge intact from the vehicle (as in 51-L). However, I am only stating this based upon location reports and photos in the popular news media.

Thankfully this crew was instantly incompacitated and never aware of the accident.

The transmission of "Roger...uh..." may reflect one of several possibilities:
1. Loss of crew module pressurization
2. Loss of comm secondary to loss of electrical power or loss of antenna/comm lines in the vehicle.

I recall that NASA stated that there was an additional 30 seconds of data that they may be able to retrieve. That data may help quantify the structural elements that were intact or not at a particular second in time.

Sadly, all this rationalization can do is assist in the investigation. It will not return the crew to Earth.

Seventeen years after OV-099's demise, I still think sometimes that I will see the crew of 51-L.

But, alas, they will remain forever young while we age.

God speed the crew of 51-L and 107!



See my post:
http://www.freerepublic.com/focus/news/833908/posts?page=26#26

http://www.freerepublic.com/focus/news/833908/posts?page=52#52

http://www.freerepublic.com/focus/news/833911/posts?page=6#6

[bonesmccoy]

WoW!

that's one heck of a pdf document!

Now I can understand why the space agency was having a debate about retirement of OV-102.

Your link shows:
1. OV-102 has a design difference from the rest of the fleet. The leading edge of the wing is structurally different in design.
2. OV-102 leading edge surfaces may behave differently from the rest of the fleet under circumstances of overheating.

I wish I had the STS-107 temperature data. You could plot the temperature data on a grid of the wing and identify where the TPS was lost.

[bonesmccoy]

Remarkable observations and application!

I'm inclined to agree.

Given that all NASA fatalities have occured within one week:

Apollo 1- January 26, 1967

STS-51-L - January 28, 1986

STS-107 - February 2, 2003

One would think that NASA's manned program may want to redouble oversight during the Christmas holiday season.

Workers may want to go home to family during the holidays, but the space effort requires great vigilance.