Posted on 02/04/2003 1:34:19 AM PST by bonesmccoy
In recent days the popular media has been focusing their attention on an impact event during the launch of STS-107. The impact of External Tank insulation and/or ice with the Orbiter during ascent was initially judged by NASA to be unlikely to cause loss of the vehicle. Obviously, loss of the integrity of the orbiter Thermal Protection System occured in some manner. When Freepers posted the reports of these impacts on the site, I initially discounted the hypothesis. Orbiters had sustained multiple impacts in the past. However, the size of the plume in the last photo gives me pause.
I'd like to offer to FR a few observations on the photos.
1. In this image an object approximately 2-3 feet appears to be between the orbiter and the ET.
2. In this image the object appears to have rotated relative to both the camera and the orbiter. The change in image luminosity could also be due to a change in reflected light from the object. Nevertheless, it suggests that the object is tumbling and nearing the orbiter's leading edge.
It occurs to me that one may be able to estimate the size of the object and make an educated guess regarding the possible mass of the object. Using the data in the video, one can calculate the relative velocity of the object to the orbiter wing. Creating a test scenario is then possible. One can manufacture a test article and fire ET insulation at the right velocity to evaluate impact damage on the test article.
OV-101's port wing could be used as a test stand with RCC and tile attached to mimic the OV-102 design.
The color of the object seems inconsistent with ET insulation. One can judge the ET color by looking at the ET in the still frame. The color of the object seems more consistent with ice or ice covered ET insulation. Even when accounting for variant color hue/saturation in the video, the object clearly has a different color characteristic from ET insulation. If it is ice laden insulation, the mass of the object would be significantly different from ET insulation alone. Since the velocity of the object is constant in a comparison equation, estimating the mass of the object becomes paramount to understanding the kinetic energy involved in the impact with the TPS.
3. In this image the debris impact creates a plume. My observation is that if the plume was composed primarily of ET insulation, the plume should have the color characteristics of ET insulation. This plume has a white color.
Unfortunately, ET insulation is orange/brown in color.
In addition, if the relative density of the ET insulation is known, one can quantify the colorimetric properties of the plume to disintegrating ET insulation upon impact.
Using the test article experiment model, engineers should fire at the same velocity an estimated mass of ET insulation (similar to the object seen in the still frame) at the test article. The plume should be measured colorimetrically. By comparing this experimental plume to the photographic evidence from the launch, one may be able to quantify the amount of ET insulation in the photograph above.
4. In this photo, the plume spreads from the aft of the orbiter's port wing. This plume does not appear to be the color of ET insulation. It appears to be white.
This white color could be the color of ice particles at high altitude.
On the other hand, the composition of TPS tiles under the orbiter wings is primarily a low-density silica.
In the photo above, you can see a cross section of orbiter TPS tile. The black color of the tile is merely a coating. The interior of the tile is a white, low-density, silica ceramic.
Glad to see you both still around.
5.56mm
Nice to see ya Bones!
It is possible, that the servers that had them are no longer active, but Budges links to his photo gallery where he stowed everything may still be up and running.
I have not checked it.
4383 - The main landing gear door is where the foam/ice hit. But the real problem was the foam on the external tank, and my post at 4303 covers it fairly well.
There is no way to make the shuttle more safe unless they solve the problem of the foam on the ET.
Take a look at the article:
http://www.freerepublic.com/focus/f-news/835531/posts?page=4303#4303
I think he told me they fired foam at a mockup of the door at the same time (about a year ago, wasn't it?) they did the tests of the leading edge.
He also told me that I was wrong on the "artificial" nature of the leading edge tests. From the photos posted here, it looked to me like the leading edge was supported both inside and outside with little glued on struts.
He told me, no, the leading edge test section was mounted just as it would have been on an orbiter, using actual flight hardware.
Apparently, those struts I saw were behind the wing in the photo, not on it.
The new ultralight tanks and some modifications on the formed ramps would eliminate this particular problem from happening again.
It is that simple!
Of course, other changes to the insulating foam package could have been done over a period of months and years while the shuttle still flew.
The likelihood of a totally different problem causing a loss of craft is actually much better than a repeat of the foam problem experienced in this incident.IMO
just my two pennies worth.
4386 - "The new ultralight tanks and some modifications on the formed ramps would eliminate this particular problem from happening again.
It is that simple!"
It really isn't that simple. Because if it were, then it would mean that NASA killed the astronauts for a very simple reason, incompetence. And it wouldn't allow them to spend all that money and time on fixes.
You need to understand NASA. Their mission is to preserve their jobs, not to get into space. If they happen to get into space, then OK, but first and foremost, mission -
"Preserve Bosses Swimming Pools".
And Burt Rutan is giving them fits right now.
you have given no size reference, so I really can't know. However, I know of no insulating material on the orbiter which would be the shape pictured, with the weight described, and the size of a coffee mug or smaller.
The colors are correct, but the weight is wrong, even for configurations around the MLG.
If it is like a coffee mug, just think, try holding a ceramic coffee mug - it is not a good heat insulator, rather it transmits heat easily. Otherwise, you would not need the handle.
PS - The HAZMAT warnings warnings were mostly 99.99% bunk, except for the OMS-RCS oxidizer tanks.
You will know if it's real by it's weight. If it weighs almost nothing, then it could be real...in which case you should contact NASA.
Real tile floats. Also, the black surface is extremely thin glass. If you push it with something metal, the surface is very brittle and will break.
The scratch marks on that piece don't look right, either.
If you want, I can put you in contact with a former shuttle guy who lives in...what the heck is it...Twain Harte, CA (or something) if you live near there.
Nobody has ever found the pieces of STS-107 which were seen by astronomers to fall off over California. I hope somebody, someday, finds them.
It's definitely not a plastic coating, I tried to scratch it with a DVM probe point.. no scratch but metal was taken off the metal probe onto the sample, so at least the surface is quite hard. I read the coating is supposed to be 16 to 18 mils thick, which is roughly 2/100 inch.. looks about right to me (the sample is only 1 inch long, the coating looks thicker because it's always cracked at an angle).
Interesting note, I read that the HRSI coating is a form of silicon carbide, *that* of course is very hard stuff. I don't think this fragment is TUFI, but I would like to know some of the characteristics of earlier tile used on the shuttle.
I'm about 30 miles from your former shuttle guy, it might be interesting to talk to him, but if the sample is far too heavy then it's probably nothing.
If the black coating is thick and hard, it's not HRSI tile.
PERIOD.
Thanks... I check in this board just to make sure that no admin is trying to insult the intelligence of the readers and to make certain that they don't try to trash my posting history.
This is the only thread worth reading now... the rest of the postings are interpreted by me to reflect the biases of a very eccentric thought process. When you attempt to engage these people in actual policy discussion, they delete your postings and then send their thought police into the thread to post diatribe and lies.
They can't pull that stunt in this thread because this thread is entirely scientific and engineering in process.
So, they can delete all my posts opposed to dual citizenship rights they want.
America is for AMERICANS... not DUAL citizens.
I appreciate your comments and your informed opinions are valuable to this thread.
Someday perhaps we might all meet for coffee and compare stories.
The recovery effort is, IMHO, stalled.
While the engineers are working to correct substantial problems, there is NO WAY recover the economics of the early STS program.
Because we've lost two orbiters, the cost of maintaining the vehicles is growing instead of diminishing and the economics of the manned flight systems we currently fly are going to increase instead of decrease.
I don't know about you, but I am beginning to think that the only way to get humans to orbit at $100 per lb. is to build vehicles that can orbit payloads at that cost.
It appears that not even Rutan's Spaceship One (a suborbital vehicle) can achieve that cost ratio...
bummer ain't it?
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