Observation on TPS damage on Orbiter

NASA photos | 2-3-03 | BoneMccoy

[XBob]

many thanks on the location north of flagstaff. I have been trying to reconstruct a timeline/geograhic position, to plug in info, observations, measurements and photos.

[Resolute]

Well, actually he said that this could have been done with foresight. Let's say that someone started with the report by NASA engineer Greg Katnik 5 years ago (Dec 1997), in which he identified debris from external tank to be a damage factor for TPS. Let's say that it was discovered that the shedding of insulation could not be prevented. I am not asserting that this happened; it is is only a hypothetical scenario.

In this hypothetical scenario, someone could have reasoned, hey, let's institute a backup plan: A. a way to investigate in-orbit for TPS damage; B. in the event of critical TPS damage, a way to get extra "expendables" (air, water, station-keeping propellant) to shuttle via unmanned backup system; C. a stopgap TPS patching solution; D. a backup way to get the crew home.

Yes, I know that the engineering challenges would be steep. However, few will dispute that NASA employs some really bright people. Instead of hobbling them with regulations and restrictions, what if some one had turned loose a mitigation "tiger team" of 50-200 really smart "rocket scientists" and engineers? I would be willing to venture that during 5 years such a team could have come up with a backup plan that would have some non-zero probability of success.

That NASA knew the foam was shedding, and damaging TPS tiles, has been documented elsewhere. That NASA knew that the loss of a single critical tile could result in burnthrough, and mission loss, is documented elsewhere. That NASA had no backup plan, no mitigation, is documented elsewhere (they stated this openly on the day of the disaster). This is profundly sad. I doubt very much that the NASA of Werner von Braun's time would have had no solutions to offer.

[John Jamieson]

Not at all interested in embarassing anyone at Rockwell or any other contractor, or NASA for that matter. I'm only interested in understanding what happened.

The TPS, was designed by RI and Lockheed, and was maintained by Lockheed and Boeing (USA). LTV actually built the RCC sections, that I think were damaged.

Please let us speak for ourselves Bones.

[tubebender]

What happened after 8:52 is pretty moot as it all began minutes earlier over the pacific. It's like watching a Indy car disintegrate as it rolls several times. When the video is studied it shows a minor suspension component failing puncturing a tire.

In all the graphics posted here I have yet to see the opening in the wing where the strut rod that attaches the shuttle to the ET mounts to the air frame. This is important because Dittemore mentioned it in day one briefing that the foam may have hit the fairing around the strut and damaged it.

[halfbubbleofflevel]

Is this what you are looking for?

You can find the "Orbiter External Tank Forward/Aft Attach Points" in at this location:

http://spaceflight.nasa.gov/shuttle/reference/sodb/2-5a.pdf

[tubebender]

More on the photo...http://www.freerepublic.com/focus/news/842855/posts

[John Jamieson]

I'm still very interested with understanding the RCC impact requirement on the RCC: No damage with a 16 in-lb impact.

I don't know of an engineering definition of impact, so I'm assuming the specification is actally an energy, expressed in strange units. If so, 16 inch pounds, would equal 1.33 foot pounds.

Energy = one half * weight/g*velocity^2

where weight is in pounds, g is in ft/sec^2, and velocity is feet/second. The final units would be in ft-lbs.

1.33=.5*.03*weight*vel^2

For 1 pound: vel^2=1.33*32*2=64+21.33=85.33 or
vel = about 9+ feet/sec.

On earth in a 1 g field v=at, or 9=32*t
t (to hit) is about a quater of a sec.

d=1/2at^2, or d=.5*32*.25*25, or 1 feet.

Are they really saying that a 1 pound weight dropped more than one foot on earth, onto the RCC, can damage it?

Maybe someone else can better define the meaning of impact.

[XBob]

1619 - "Yes, that is the AZ video. I studied it, but could not save it, and my links do not work anymore either. I believe the footage has been zapped. Or the damn Real Player has crapped. "

exactly my experience, every time I look at a reference which might have been it.

[tubebender]

Thanks...that shows it inboard of the wing and well aft. I doubt the foam hit there by the debris exiting out board of the wing tip.

[Thud]

The detached foam was deaccelerating in the air blast at Mach 1.5 while the shuttle was continuing to accelerate up towards the foam. The relative velocity is the difference between the foam's velocity lost in the air stream and the velocity gained by the shuttle as it accelerated, all in the interval between the foam detaching from the fuel tank and it striking the shuttle.

[John Jamieson]

That's true, but what does it have to do with what I posted?

[XBob]

1624 - "What happened after 8:52 is pretty moot as it all began minutes earlier over the pacific."

The first indicators of anything out of whak was at 8:52:20, the first anomalous temp rise, well out over the pacific.

"In all the graphics posted here I have yet to see the opening in the wing where the strut rod that attaches the shuttle to the ET mounts to the air frame."

the forward attach point is right behind the front wheel well.


" This is important because Dittemore mentioned it in day one briefing that the foam may have hit the fairing around the strut and damaged it."

Looking at the video from the ice team, There is a possible initial glancing hit of the 'foam' in approximately near the forward attach point, however, there was no apparent damage, or reports of damage or out of whak sensors or photos, or anything of any problems in this area in anything I have seen.

[John Jamieson]

It's interesting that NASA assumed a 10 to 16 degree angle of attack for foam hitting the tiles. The foam could have hit the RCC at the full 90 degrees.

I didn't catch the stuff about the possibility of two pieces, but if so, a leading edge hit would seem to be the best fit.

[Cold Heat]

I doubt the foam hit there by the debris exiting out board of the wing tip.

We studied the impact days ago. What we found was that the foam impacted in the gear door area, perhaps the front of it.

The appearance of the cloud exiting the wing in the way it did, is explained by the angle that the foam came from. It came from the forward mount which is located forward and center of the orbiter.

If you draw a line between the points, it seems to line up with the angle of exit. Also, the dust was accelerating much faster than the foam piece and seemed to exit almost into the camera direction. Again, those angles correlated to the path of the foam.

[freepersup]

Did you happen to catch this in # 1618 ?

The search for debris from Columbia continued in Texas, where a preliminary analysis of low-frequency sound wave recordings indicated the shuttle exploded between the cities of Amarilla and Lubbock, about 330 miles west of Dallas.

[Cold Heat]

The other piece dissapeared going down toward the boosters.

[Cold Heat]

Yes, that would be about right.

[John Jamieson]

How sad, wasn't the pilot from Amarillo?

[freepersup]

# 1626: This story is incredible ... one exposure of the shuttle in a 24 second window of opportunity- horizon to horizon. Wrote the software to track the shuttle the night before...

[freepersup]

Husband, a native of Amarillo, Texas, where he lived with his wife, Evelyn, and their two children, had served as a pilot on a previous mission aboard the space shuttle Discovery, and logged more than 235 hours in space.

A certain irony to his death occurring so close to his home town...