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Einstein's Energy
2003-Feb-16, 10:55 PM
After more than two weeks of investigation and study, there is still no certainty about how or why the left wing area got damaged, or even if penetration damage was the triggering cause of the craft's breakup.

Amid all of the other physical evidence and speculation thereon, it's amazing that a fully detailed analysis and time-series plot of the left wing temperature/pressure data alone, and subtracted from the corresponding right wing set of data was not done, even shortly after launch!

Rather than banter about the abilities of programmers, why not set them on the (relatively) simple task of up-close analysis of this crucial, and possibly determinate data set?

A look at the wings' temperature profiles especially during the orbiter ascent and last 20 minutes of re-entry, might easily show whether the fuel tank insulation penetrated and/or damaged the wing/landing gear compartment. If any anomalous changes were sensed (especially differences in left/right wing data values)during ANY portion of the several-day mission, it might discern launch-phase damage from a later collision/breach while in orbit. (Even if no significant deviations were detected, a comparison of the temperature profiles in that area with prior (normal) missions on that vehicle might be worthwhile.)

If the piece of insulation compromised the fuselage, then the rate of change (cooling) of most of the temperature sensors in the left wing should have dramatically increased, due to turbulent ambient air (-50 to -60C) entering the hole.

Even during stable altitude residence in orbit, a (numerical)difference in all left wing temps from right wing temps might also be confirmed, depending on whether the gear cavity was facing the earth (reflected radiation heating), space (longwave cooling) or even the sun (intense long and shortwave heating)

Even without air pressurization, a hole or skin gap could affect the airframe/fuselage heat gradients from inside the craft outward radially from the main fuselage, particularly when compared with temperature values from the right wing temperature sensors.

Finally, if nothing was found significant when comparing temperature rate-of-change or steady state differential (left to right) readings after launch and soon after orbit stabilization, then a lot more credibility could be given to collision with later space debris, or some other failure mechanism involving the left wing and gear cavity.

I would propose that if this data has been processed, that it be tabulated, plotted and released to the public. If not, then priority processing of detailed telemetry data (by NASA, or some other entity) is urged.

Submitted, R.D. Horn

calliarcale
2003-Feb-17, 11:08 PM
Firstly, NASA actually *has* been collating this data since the incident. That was the very first thing they started doing. They actually physically locked everybody in the building and wouldn't let them leave until they'd written down a statement of what they'd done and observed. All data was impounded so it could not be modified until it had been entered into a database of some sort so that it could be collected into a timeline. They finished doing that sometime in the past week or so, I believe, and the information actually *has* been released to the public, though I don't think it's been released in a hugely detailed way. I haven't been looking particularily hard myself, but I have observed some very good diagrams in my casual searches giving a general overview of the results, marked with the times at which each failure was noted.

Now comes the much harder part -- figuring out what actually physically happened. You really can't figure that out from sensor data alone. Sensor data can provide some excellent clues, but they're going to have to look at the wreckage too. Even then they may not be able to figure it out; the debris is broken into some awfully small pieces and they still don't have a lot of the bits. Plus, unlike the Challenger disaster, the bits will have had to endure reentry, and that will make it even harder to tell which damage was from the accident and which damage was from the aftermath.

Nanoda
2003-Feb-18, 09:18 AM
Agreed. The data is important, but you don't see the FAA leaving a crash site after finding the black box, and they don't issue a cause right after reading it.

If it's processed data you want, it's only 1 click deep off of NASA's front page (http://www.nasa.gov) today (and for the last few days), labled Ground Tracks (http://www.nasa.gov/columbia/107_ground_tracks.pdf).

Kaptain K
2003-Feb-18, 06:18 PM
Amid all of the other physical evidence and speculation thereon, it's amazing that a fully detailed analysis and time-series plot of the left wing temperature/pressure data alone, and subtracted from the corresponding right wing set of data was not done, even shortly after launch!
What makes you think it wasn't done. Just because you haven't seen it in the mass media, doesn't mean it wasn't done.

<font size=-1>[ This Message was edited by: Kaptain K on 2003-02-18 13:22 ]</font>

Einstein's Energy
2003-Feb-19, 05:51 PM
[quote]
On 2003-02-18 04:18, Nanoda wrote:
Agreed. The data is important, but you don't see the FAA leaving a crash site after finding the black box, and they don't issue a cause right after reading it.

If it's processed data you want, it's only 1 click deep off of ...

Thanks for the reply. Maybe you missed my point though. What I'm talking about is the telemetered data, not the black box data (if it even exists). I looked at the ground track data, but it's not very important compared to the launch, ascent and stable orbit data. (as I pointed out regarding the temperature profiles of left vs right wing sensors.)

My reasoning is that if a hole or gash was made 'anytime' in the flight that was big enough to allow 'that' much hot plasma entry (to quickly destroy the gear cavity and wing), then it also could have clearly shown abnormal conditions long before the re-entry phase.

I doubt that NASA has looked at the data set in the manner that I am proposing, because when they finally do... it will show something significant.

I would like to submit this (data-supported) scenario to NASA in some way, but how? Do you know of a suggestions box somewhere on their site? Or a contact name?

If so, let me know.

Einstein's Energy
2003-Feb-19, 05:58 PM
[quote]

What makes you think it wasn't done. Just because you haven't seen it in the mass media, doesn't mean it wasn't done.

Well, see my reply above. My guess is that if they *had* looked for this kind of signature, they would have seen the breach, announced it, and drastically changed the nature of the mission. I guess only time will tell.

CJSF
2003-Feb-19, 06:59 PM
EE,

That makes no sense. Any discrepencies would have shown up after the de-orbit burn and start of re-entry. There's nothing to do after that.

CJSF

Thumper
2003-Feb-19, 07:41 PM
On 2003-02-19 12:51, Einstein's Energy wrote:
My reasoning is that if a hole or gash was made 'anytime' in the flight that was big enough to allow 'that' much hot plasma entry (to quickly destroy the gear cavity and wing), then it also could have clearly shown abnormal conditions long before the re-entry phase.


The latest thinking is that it was not plasma that entered through a hole in the left wing/landing gear bay, but hot gases. See Here (http://www.space.com/missionlaunches/columbia_questions_answers.html#plasma). Maybe it's just a question of semantics but it is looking like the first anomalous sensor readings occured when the shuttle was too high in the atmosphere to create plasma. The air is too thin and plasma isn't created until the shuttle is lower and slams into thicker air.

The link above is an FAQ page with links to some of the latest theories and news. The temp sensors indicated an abnormal rise but not as high as you would expect from plasma invasion.

WHarris
2003-Feb-19, 08:00 PM
On 2003-02-19 12:58, Einstein's Energy wrote:
[quote]
Well, see my reply above. My guess is that if they *had* looked for this kind of signature, they would have seen the breach, announced it, and drastically changed the nature of the mission. I guess only time will tell.


The hot plasma/gases wouldn't get into the wing until the reentry phase began. Since space is a vacuum, there's no way to tell if there was a breach there beforehand.

calliarcale
2003-Feb-19, 10:28 PM
And there's the rub. A lot of sensors on aircraft, including the orbiter, don't work in space. As far as aviation goes, an orbiter in space is basically parked -- most of the sensors have nothing to detect. Airspeed reads zero, drag is so negligible it's not even remotely measurable, hydraulics have nothing to do because the control surfaces don't work anyway in space, and so on. Those sensors that *do* have something to report (basic systems health, temperatures, internal pressures, etc) all reported normal values. In fact, before the landing, NASA officials were talking about how amazingly *normal* the flight had been -- they launched exactly on schedule, orbit insertion was perfect, all burns were perfect, all science objectives were completed, and weather was perfect for an ontime return to Florida. In hindsight, a melodramatic person might say that things were "a little *too* perfect."

By the time they knew anything was wrong, it was much too late to do anything about it. Once the deorbit burn (another maneuver that was completed exactly perfectly) is completed, the vehicle is committed to a particular glide path and landing.

A direct reply to Einstein's Energy:

Thanks for the reply. Maybe you missed my point though. What I'm talking about is the telemetered data, not the black box data (if it even exists). I looked at the ground track data, but it's not very important compared to the launch, ascent and stable orbit data. (as I pointed out regarding the temperature profiles of left vs right wing sensors.)

What you have been provided *is* the telemetered data. There is no black box. There are recorders (though they are not ruggedized in any way like aircraft flight data recorders) but they have not yet been recovered -- assuming they have survived at all. The important data, however, is sent to the ground live via telemetry.

NASA officials examined the ascent telemetry on Flight Day Two. This is standard operating procedure. Everything looked almost surreally normal. The only indication of anything abnormal came not from telemetry but from tracking cameras -- the chunk of foam (and possibly other stuff) coming away from the ET and striking the orbiter. The investigation team is taking a fresh look at ascent telemetry to see if they can spot anything the original team missed.

Orbital telemetry showed no signs whatsoever of a problem. However, there are a great many things that would *not* have shown up because there just isn't any way to get a sensor to test for them. One theory that has recently been offered is that Columbia's left wing may have been rougher than the right due to older tiles on that side (70% of her tiles were original to the vehicle and have been on her since before STS-1). That could induce drag and perhaps even structural stress, but you can't sense that without air to produce drag. Another theory involves damage to the leading edge of the wing or perhaps to the seal around the wheel well or another location that had occured sometime prior to reentry, which allowed hot gas to get into the wing itself. This also cannot be detected with a sensor; in space, unless you are in a pressurized environment, there is no way to tell if you've got a leak because there's nothing *to* leak. And then, of course, there is the failed thermal protection system (lost or damaged tiles) theory, but there, you would only sense lost tiles by an abnormal heat rise, and that will only happen during reentry. So by the time you know what's going on, it will be too late to do anything but pray.

Frankly, this is what spooks me out the most about this. The failure may be something undetectable which cannot be corrected because it is a fundamental risk of spaceflight. What if the breach was caused by a micrometeorite? The only way to be safe from those is not to go into space at all.

johnwitts
2003-Feb-20, 02:45 AM
Are the wheel wells vented? At launch they are full of air, and in space they are full of nothing. How are they vented?

<font size=-1>[ This Message was edited by: johnwitts on 2003-02-19 21:46 ]</font>

Einstein's Energy
2003-Feb-20, 06:51 PM
[quote]
On 2003-02-19 17:28, calliarcale wrote:

1) And there's the rub. A lot of sensors on aircraft, including the orbiter, don't work in space. As far as aviation goes, an orbiter in space is basically parked -- most of the sensors have nothing to detect.

2)The important data, however, is sent to the ground live via telemetry.

3) NASA officials examined the ascent telemetry on Flight Day Two. This is standard operating procedure. Orbital telemetry showed no signs whatsoever of a problem.



4) ...However, there are a great many things that would *not* have shown up because there just isn't any way to get a sensor to test for them.


5) ....which allowed hot gas to get into the wing itself. This also cannot be detected with a sensor; in space, unless you are in a pressurized environment, there is no way to tell if you've got a leak because there's nothing *to* leak.

General response first; For some reason, some of you who are responding either failed to read all of my original post on this temperature issue, or else you are *still* missing my point.

Now, numbered quotes from above;

1) NASA obviously doesn't place thermal sensors in air spaces (the wheel wells) and then record flight data that is meaningless because there is no *temperature* to sense. The sensors I refer(ed) to are embedded in the gear assy, and/or airframe, a little behind the wings. They measure the temperature of the aluminum structure at that point.

1b) Likewise, the tire pressure is a valid 2nd order indication of the mean (averaged by the thermal mass of the wheel assembly) temperature of the hubs and tires, ok? Both these sensor types work just fine in a vacuum, agreed?

Because of this I maintain that IF a fuselage breach occurred (a hole or open tear), especially on ascent, due to the foam and/or ice, then the entire cavity (wing/gear) would be flushed with icy cold air (shuttle was still at or above the tropopause),THEN the temperature sensors and the tire pressure could reflect that rapid cooling by direct reading.

2) Yes, this data stream is realtime and presumably transmitted with little or no averaging, it is around one to five seconds per measurement.

3)Yes, NASA claims to have peered at the data and found nothing *significant*. What is actually contained in the unprocessed, un averaged data set might be measurements of far greater resolution than NASA's *routine* scans. Certainly most sensors and data acquistion can resolve 0.1 Deg F over the range of interest, and at a temporal resolution fast enough to recognise events and conditions that change within a fraction of a minute.

So, unless NASA does onboard averaging, or range of data compression (before transmission) that would prevent such a detailed analysis, then there is a LOT of potential for events, trends, offsets to be detected, ESPECIALLY when the sensors are normalized (differenced) with the corresponding data from the right wing area.

4)Agreed, a sensor cannot be deployed for every type of event or condition possible, but I am simply saying that the sensor data that does exist, might be used as a hypothesis test for IF and when an actual wing breach occurred. Also agreed, that these sensors probably *wouldn't see* anything relating to external damage ie; tiles missing, or damaged.

5) Again, your comment refers to events on the RE-ENTRY phase (sensing in a vacuum. Part of my logic is that the most reliable clues might NOT be in the last minutes or seconds of the flight. During the violent destruction of the orbiter, ANY data that is taken sensor wise, is more unreliable and possibly even conflicting, due to the failure of both mechanical structures, and the wiring and data acquisition systems that monitor them!

As my original post stated, I believe that if clues are embedded in the telemeterd data, then they would be most valuable (or only valuable) during the upper ascent and then only possibly (depending on hole size vs radiational heating/cooling) during stable orbit conditions.

Does this now make sense?


To conclude, I also agree that the critical *thing* that caused this catastrophic mission fate might never be pinpointed, or if it is, will be after a long and costly effort. I wish NASA the best.

RDH

calliarcale
2003-Feb-20, 07:14 PM
EDIT: Reread your post. I understand now. Sorry for the confusion; I've been coping with a cold.

The telemetry from the ascent was reviewed as part of standard operating procedures and is being reviewed again. All values were nominal -- they did not reveal anything abnormal, so I'm afraid that's a dead end.

It's questionable whether or not they *would* -- it takes a lot to heat up those particular sensors, and ascent doesn't actually put that much strain on the thermal protection system. The final part of ascent puts even less strain on them, because they have gotten above the atmosphere and are operating in a near vacuum.

<font size=-1>[ This Message was edited by: calliarcale on 2003-02-20 14:18 ]</font>

Einstein's Energy
2003-Feb-20, 10:58 PM
On 2003-02-20 14:14, calliarcale wrote:
EDIT: Reread your post. I understand now. Sorry for the confusion; I've been coping with a cold.

***** Thanks, for a while I thought I must be completely mad! (Sometimes the more I try to get a point across, the less I am understood at all.)

The telemetry from the ascent was reviewed as part of *standard operating procedures* and is being reviewed again. All values were *nominal* -- they did not reveal anything abnormal, so I'm afraid that's a dead end.

**** Well, again... the key words are as you put them... *SOP* and *nominal*. Since there never was a (prior) breach of that magnitude due to the insulation hitting the craft, then how would SOP expect to reveal it? What is the criteria for *nominal*?

Please remember that the leaking "O" ring problem that betrayed the Challenger launch was also accepted as *SOP* and or *nominal* as well. The rountine acceptance of a disasterously dangerous condition (SRB blowby)... being beaten, or inconsequential, was among the most telling examples of organizational/managerial override of technical staff. The lesson there was... it doesn't pay to keep playing russian roulette as though 'skill' or 'luck' will see you through. Never.

If all NASA did was to use integer values of Deg F and "trend" estimates(such as on the ground-track plots) ... would that be enough sensitivity to detect an anomaly? Only a more detailed look can tell. Maybe that coupled with physical modeling in cold/low pressure wind tunnels could resolve that.

It's questionable whether or not they *would* -- it takes a lot to heat up those particular sensors, and ascent doesn't actually put that much strain on the thermal protection system.

***** Again, you are missing my exact point. The structural parts in which the sensors are embedded, should be COOLING at some measurable rate during the entire ascent profile. Not heating. And, as was shown in the huge "trend" of temperature values of the last several ground track flags as published buy NASA, the structures are not so massive that they cannot be seen to undergo several degrees F per minute, or even per second.

Allowed, that the driving force (heated air) on the structure/sensors due to re-entry friction is much greater than the cooling force possible through a tear or hole during ascent with turbulent cold air entering etc etc, I still maintain that any appreciable hole,gash or leak, coupled with an airspeed of what, 12,000 miles per hour(?)penetrating into what should be dead air space... ought to be quite detectable with those sensors.

The final part of ascent puts even less strain on them, because they have gotten above the atmosphere and are operating in a near vacuum.

***** Yes, true... but on the other hand, what better way to detect (abnormal) structural heating or cooling due to possible exposure of the cavity to the outside world? The fact that in orbit, there is no molecular phase (air)dissipation of heat... means that any radiational exchange with space... (the earth, the sun, deep space) might now be AMPLIFIED instead of.. as you stated...be supressed or not detectable by the embedded sensors... and especially the tire pressure... due to the blackness of the tires compared to low emissivity metals, aluminum, steel, etc etc.

All of this conjecture is based on some finite sized hole or tear in the wing/gear area. That is... several inches or more. Obviously, a tiny fissure or puncture might not be enough to cause measureable differences in the gear area... but on the other hand...the kinetic energy released by a 2Lb (or much more,if it was ice) object hitting MY wing at 500 miles an hour would make me uh... somewhat anxious, even depressed.



<font size=-1>[ This Message was edited by: calliarcale on 2003-02-20 14:18 ]</font>