Sign in to follow this  
Guest Barney1

Shuttle Tank ruled out? So soon?

Recommended Posts

Press today is reporting that NASA is saying that the dislodged "foam" (which is actually rock like in hardness) probably didn't cause enough damage to the wing to cause the accident. I am curious--how can they say that so soon? The shuttle was reported as moving about 1900 mph at the time the foam was seen coming off the tank. The foam would have quickly accelerated and hit the wing at a very high speed. Imagine someone throwing a two pound rock at a vehicle going 60 miles an hour, let alone 1900 mph....Isn't it better that NASA keep mum on the subject? Or are they trying to shift focus away from a cause which many have warned about for years?Even if the foam strike was not a direct cause, it most certainly seems to have triggered the course of events that lost the shuttle, assuming it changed the drag profile of the left wing. I have wondered (and I've heard mention of this in the press), whether the drag issue on the left wing caused the computers to overcompensate. Is it possible that the control surfaces were deflected enough that they were torn off? This could have caused the shuttle to break apart as it entered thicker atmosphere, as it might have started a roll or pitching motion, exposing parts to undue stress... With the G-Forces involved during reentry, the crew might not have felt any odd changes in the shuttle's attitude. I saw the video over Nevada this AM, and it clearly shows a bright flash, and then a bright trail directly behind the shuttle. I suspect it took more than a tile or two falling off to produce that. I am hardly one to embrace conspiracy theories. But one thing is certain--people's livelihoods will depend on the truth. If the foam on the tank was a known risk, but was conveniently ruled out, a lot of people would rest easier, wouldn't they?I can only guess at these things, as we all can (even the experts are largely guessing, due to the wait and search for data), but I'm beginning to fear the idea of a shuttle ever going up again. We have a need to explore space, but not at the expense of keeping someone's budget intact. The time has come to replace the shuttle, I think. Let's keep people in space, and reduce the risks to get there, even if it means a few years off to get the job done. If we do need to send the shuttle up to service the International Space Station, let's keep the crew size down, and let's bring it into Edwards, so that reentry isn't taking place over populated areas, and risking the lives of those below. Regards,John

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

As they say... it "probably" didn't cause it. I wouldn't say they've *ruled it out*, because they aren't certain that it was not the cause. Through their scientific reasoning, I guess they feel that the damage necessary to mortally wound the shuttle wouldn't have come from that foam shard, or perhaps that foam shard alone. They are providing us with information on-the-fly, and as situations change and as they learn more, anything and everything is subject to change. I'm sure they have their reasoning for discounting it - but I wouldn't say they have ruled it out and are no longer looking at it whatsoever.

Share this post


Link to post
Share on other sites

John,I saw most of the press briefing yesterday. The debris issue certainly has not been ruled out - nor has anything else - but they aren't as confident that it was the root cause. They've re-run their foam impact analysis from scratch and are still not seeing anything that could have caused catastrophic damage. They also showed several frames from launch film that had a clear view of the left wing underside, both before and after the foam impact. No gross damage could be seen. Mr. Dittemore cautioned that the film was not of sufficiently high resolution to see smaller damage to the tiles, but a large, deep gash like they were talking about earlier, on the order of 20 - 30 inches long, should have been visible.A couple of clarifications to your post: Even though the vehicle may have been at about 1900 mph at the time of impact, the area of interest is the narrow slot between the tank and the orbiter underside. That area does not see the full freestream velocity. They estimated the foam chunk velocity to be about 600 fps, then to be conservative they doubled that to 1200 fps for their analysis. There should be a lot of confidence in that velocity. You know the frame-per-second capability of the camera, and can get a pretty fair measurement of how far the chunk moved between frames.Also, the foam is not "hard as a rock." It is rigid, but very light weight, almost like styrofoam. You can easily pick up a 1-foot square chunk of it with one hand and raise it over your head. They also pointed out that since it's a closed-cell material, it does not absorb water at all. Water just runs off it like a duck.I tend to agree that they might be trying to be a little too open about the investigation. They're in a no-win situation. If they are very candid and share information and theories as the investigation progresses, they might appear to the uninformed to be indecisive or incompetent just because in the early days the focus will inevitably change from day to day, as is normal in accident investigations. OTOH, if they keep quiet until everything is finalized, people will start whispering cover-up (NOT REFERRING TO ANYONE IN PARTICULAR ;)).Dan

Share this post


Link to post
Share on other sites

Thanks for the clarification Dan..... Sorry to say, my description of the foam comes from the press--the only source for most of us. Since the accident, I have been very curious about the path of the shuttle. Was the path over Texas where it was expected to be, given that stage of the descent? I really don't know at what point drag on the shuttle really begins to influence its path. I hope NASA is looking at that as well--any deviation in the path might give them an idea of when "events" happened. I have no idea how much a change in a wing could influence the shuttle's path at those speeds and altitudes...

Share this post


Link to post
Share on other sites

John,Heres a pretty good summary of the news conference yesterday. I wasn't too far off with my description.I haven't heard much about the trajectory, but I assume it was initially right on the money since there's been no discussion of anything abnormal until the last several minutes.Dan

Share this post


Link to post
Share on other sites

The press has been giving out all sorts of faulty conjecture fm the beginning. Minutes after the accident, there was reporters saying the shuttle "blew up," as if they KNEW there was an explosion on board. Another was saying that the space shuttle with the Isaeli pilot (implying that he was flying the Columbia) "crashed" in Palastine, Texas. First off, it didn't crash or explode, it broke up on re-entry. Secondly, it certainly didn't crash in Palastine TX, the reporter just said that for sensationalism b/c the Israeli was on board. On Tues morning I was still hearing reporters saying authorities were still looking for "the black box" in NE Texas after the shuttle's explosion. Just about every word out of their mouths is incorrect. The shuttle has no black box like an airliner, instead, hundreds of bits of data and telemetry are being fed down to Mission Control in real time. "Crash" implies it hit the ground intact, which is certainly did not. Someone else on this site has been implying that the ET was flawed, and questioned why NASA launched a heavier/older-type model ET. Duh, b/c the Columbia wasn't headed to the Space Station and had no need for a light weight ET. Why not use up all the heavier ETs when you can, and put our tax dollars to work ---it certainly was no conspiracy. How many people have you heard ask why the Columbia didn't simply go to the Space Station instead? I won't even begin on how stupid that comment is. Even that idiot Hoagland was on Coast-to-Coast trying to make an argument for a space rescue and a conspiracy. As Yogi might have said, "Half of what you hear is wrong, and the other 60% isn't right either."

Share this post


Link to post
Share on other sites

"How many people have you heard ask why the Columbia didn't simply go to the Space Station instead?"That comment hits home.... Can't tell you how many people I've heard with that question.A link posted earlier had a very good FAQ section regarding why Columbia couldn't go to the ISS. That's assuming damage could have even been detected.I am an avid fan of the orbiter simulator... Even if the shuttle had the fuel to reach the ISS, it's not the same as driving to Grandma's.... It takes work to synch orbits, and it's a heck of a lot harder once you're in space already. That's why launch windows are so important, so one can rise to an interception point as efficiently as possible.I am anxious to see how the X-prize project goes (www.xprize.org). Throwing such creative resources at the problem of spaceflight as private enterprise, we might see a new approach, and perhaps an approach more quickly deployable than a government funded shuttle replacement. Personally, I wonder if "swing-wing" technology combined with some type of water landing ability might be the most effective way of having the type of flexibility the shuttles offer. If you could stow the wings inside the fuse during the stressful parts of launch and reentry, one can really reduce the amount of control surfaces exposed to danger. The weight of the mechanism required to control the wings could be offset by not having to support landing gear. Just a thought.... Hmmm... Have to get to work on FSDS 2 now..... :)

Share this post


Link to post
Share on other sites

I agree with what you are saying. There is so much BS and hype out there about the accident that its more than frustrating. That the press is a huge part of this doesn't surprise me in the least: the most sensational journalism sells to (and reaches) the most people. Advertisers are, of course, in seventh heaven. And thats what matters to the vast majority of popular press these days.Not many years ago the majority of the popular press could be trusted as a valid source of accurate information (think the 70's and 80's era before MTV came along). Today, the vast majority of the popular press is simply that: popular reporting. Facts and actual hard work digging into stories to "get it right - the first time" has lost out to printing the first sensational thing some bozo source will backup - regardless of that source's validity.---One thing really bother me about the shuttle program and NASA's oversight, however. NASA keeps repeating that it would be "impossible" to do anything about any missing tiles or underside damage even if there *was* known launch damage and they wanted to fix it in orbit. The reason they give: the shuttle wasn't equipped with the CANADARM or Manned Maneuvering Units (jet packs) to take pictures of the underside or make an EVA (since there are no tethers on the underside) - let alone replacement tiles in the case of missing, damaged or loose ones. Hence, even though they were very seriously assessing the possibility of tile damage from liftoff, they couldn't physically check to verify, or do anything about it even if it was verified.Why? Thats exactly like taking a meticulously planned drive through the Mojave Desert, but purposely emptying the trunk of a spare tire - and leaving with a half a tank of gas. Sure, you'll definitely get better fuel milage - and you might even make it to the other side. But your probability rating doing so just plummeted. Its simply ridiculous.Why on earth would you repeatedly launch a vehicle into orbit without the necessary equipment and training to handle a possible external problem that you *knew* the fleet had constant, if manageable to date, trouble with throughout its lifetime? Why wasn't the CANADARM required on *every* flight, regardless if it was needed for the tasked mission? Why weren't there at least two Manned Maneuvering Units - or even the less capable emergency units on board at all times for just such emergencies (and many like possibilities: damage from orbiting debris - of which there is massive amounts - or tiny meteors, etc)? Why wasn't there a set of replacement tiles stored in the cargo bay area - or at least some advanced, researched emergency heat blanket type of "patch" available?Lets not forget: NASA now has slightly less than a 1 in 50 failure rating with the shuttle program. You'd think they'd be all over a potential set of problems like this. Yet, they simply state in all their press conferences to date that an in orbit repair would have been impossible. End of discussion.NASA *is* correct: it was and would have been impossible to do anything about any tile and underside damage the way the shuttle was configured and crew was trained. But the fact that it *wasn't* configured for such a probable set of events and its crew *wasn't* trained to handle something like this is part of a big NASA problem in my mind. And, I might add, the government's shrinking NASA budget over the years.Thats not to say damaged or missing tiles were the root cause of Columbia's failure. Only time and thorough investigation by NASA will determine that. But having the fleet equipped (and the astronauts trained) to make emergency EVA's *might* have saved this crew. And it certainly might save any future crew that encounters a debilitating problem like this. Considering the tile history and external damage potential due to the myriad of other [link:www.space.com/missionlaunches/sts107_space_impact_030205.html]possible factors, that simply must not, cannot be acceptable.Baffled (at the rabid press and NASA),Elrond

Share this post


Link to post
Share on other sites

Elrond,I don't disagree with what you're saying, just have a comment about in-orbit tile repair that most people don't think about.I believe the tiles are applied to the orbiter structure with some kind of adhesive. Don't know exactly what kind, but I'll try to find out. The problem is, adhesives have to cure under tightly controlled environmental conditions. Part of my job involves the bonding of a carbon composite to the SRB exhaust nozzles. The carbon serves as a protective shield. We do the bonding in a clean room that is very tightly controlled (particulates, temperature, humidity). I'm not sure if bonding in a vacuum would work at all - the adhesive might just bubble out. Also, the temperature extremes are immense, and they swing from one extreme to the other every half-hour. Finally, if you developed a bonding process, it would be difficult to test it. Testing would have to include subjecting the bonded tiles to re-entry conditions.I'm not saying it's impossible, there's just a lot more to it than first appears.Dan

Share this post


Link to post
Share on other sites

Hi Dan,I'm glad you responded - I'm gaining a real respect for your thoughts concerning the shuttle program and Columbia in particular.I have no doubt that a solution to this would involve seemingly impossible difficulties and guaranteed cost. But I also have no doubt that when its solution was considered required by NASA, even if it precluded the existing method of attaching replacement tiles with adhesive as from the ground - or replacing tiles in-orbit at all for that matter - the solution would be researched and found. Overcoming difficult barriers, even when thought impossible, is exactly what NASA is tasked and budgeted for... And of course been successful at for so many years.The problem I'm really talking about here isn't a particular solution or the difficulty and cost arriving at one: its the lack of NASA oversight to *act* on risk assessment that pointed out such a deadly problem long ago. Regardless of the reason, this cannot be tolerated: its exactly what 1986 and Challenger was supposed to have taught NASA. Repeatedly saying in press conference that a picture of possible damage or an EVA to fix it was impossible skirts the evident: it was only impossible because it wasn't a priority.Indeed, its not hard to assess the risk involved in massive amount of space junk sharing orbit with and meteoroids visiting with the shuttle fleet - and the [link:www.space.com/php/multimedia/imagedisplay/img_display.php?pic=hubble_hole_photo_0202_02.jpg∩=This%20three-quarter-inch%20hole%20in%20Hubble's%20high-gain%20antenna%20was%20photographed%20during%20a%201993%20servicing%20mission.%20CREDIT:%20NASA/JSC]probabilities of such an incident]. That doesn't include the myriad of other accidents - exactly like launch damage[/i - that can happen on the exterior of the shuttle fleet (we of course remember Apollo 13 here as well).NASA *could* and *should* be prepared for tile and other external damage it might face - but its not.Thanks for the insight you keep providing on the mechanics of shuttle processes. I'd indeed like to hear more about how the tiles are attached if you are able.Take care,Elrond

Share this post


Link to post
Share on other sites

Some other points to consider:1) Number of tiles (20,000 +/-) and where they fit. Which would you carry with you? Otherwise, some way of manufacturing on board required.2) Action/reaction....when one pushes he tends to drift in the opposite direction.....how to tether someone in EVA and ensure they don't cause more damage while assessing damage and applying the repair?3) Some of the crew would need to do EVA training.From the little I've been reading lately, there was thought and planning to enable this very thing during the very early stages of Shuttle flights, but it became apparent that there was more risk involved versus the dubious benefit, and thus discarded. Dubious, because as has been stated and shown over the history of the Shuttle, loss and/or damage of individual tiles hadn't been severe enough, in and of themselves,(no burn-through of underlying skin) to have caused catastrophic results prior to STS-107.

Share this post


Link to post
Share on other sites

There is no such thing as repair. If the tiles were damaged that ship was doomed from the start. But...the crew was not. There is a SPACE STATION out there. Go fly up, park the shuttle beside, float over.And before SOMEONE yells at me for "float over", get real. That is exactly what I mean. We have tethers.No matter what the cause, after the history of tile damage, after the BIG chunk O' foam hit the shuttle at hi-velocity, it cannot be ruled out so QUICKLY that the foam did not do it.Meteor? Far less likely.Best,bt

Share this post


Link to post
Share on other sites

[uL][li]Vehicle was loaded with equipment for mission research and crew supplies instead of the propelants needed to reach orbital altitude of space station. Heavier early model external tank also reduced potential altitude. Unlikely it would have been able to reach station altitude even early in mission.[li]Orbits can be in different planes around the parent body. Possibilities include angle relative to equator and direction of the "tilt". Direction of "tilt" is established by timeing of launch. Without intentional planning before the flight, Columbia probably had a different orbital plane and would have required an enormous amount of propelants to reach the space station.[li]Docking adaptor not aboard orbiter. With no means to maintain position relative to the station both vehicles would be endangered by the possibility of drifting into each other. The hazard from this would be similar to the docking accident that disabled a module on the Mir station. The station has numerous long protruding solar panels and heat dispersion radiators. It would be dangerous to maintain a position within reasonable tether reach without the ability to dock.[/ul]

Share this post


Link to post
Share on other sites

"...taking a meticulously planned drive through the Mojave Desert, but purposely emptying the trunk of a spare tire - and leaving with a half a tank of gas"Unfortunately being prepared to replace ANY damaged tile, add a docking module, add the remote manipulator (which probably wouldn't reach under the wing anyway), and add the propelant nessesary to reach the altitude of the international space station would be like carrying four oversize knobby offroad spare tires (complete with rims) a complete set of replacement exterior body panels, and several 55 gallon drums of gasoline. Under such circumstanses you wouldn't have any room to sit in your SUV to drive.Imagine your SUV needs a tanker truck full of gas (the external tank and solid boosters) to get close enough to the desert to drive there. You and your passengers need ALL of the SUV's cargo area and roof rack for the water and supplies to survive and complete your assignment in the desert. Leaving items behind to make room for gerry cans of fuel or extra spare tires would mean sacrificing the mission that justifies the trip in the first place. Even leaving the abandoned tanker behind with a dry trailer and dry diesel tanks on the tractor after the last fill up leaves you with just barely enough gasoline to reach the top of a long steep grade down from the edge of the desert on your way back. Keeping your SUV under control coasting down the slope requires riding the brakes to the verge of failure from overheating. By the way: the tractor (the boosters) left the empty tank on the mountain and coasted back down the slope itself. You are hopeing some automaker has an SUV on the drawing board with a more efficient engine and or ligheter weight composite body so you will, on some distant day, be able to get an SUV that gets better mileage. Of course affording the SUV of the future will require new financing from the bank (congress) and your not sure you will be able to qualify.

Share this post


Link to post
Share on other sites

Nice analogy, RobertVA.And you can bet that that SUV "on the drawing board" won't be cheap.Funny... you can bet the folks stuck out in the desert with all their provisions, fuel, spare tires, and no experiments to conduct surely would pay a princely sum for that new technology.That's where we're at right now. Folks are saying the shuttle should be retired, and bring on the next generation. Until the bills have to be paid.Greg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this