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#11
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New Columbia loss report out today
From M :
http://www.nasa.gov/pdf/298870main_SP-2008-565.pdf It is the most detail accident report I have ever read in my life. I had access to Air Force accident reports while I was in the service, and I read AW&ST accident reports on airline accidents. This report is very very detailed. The Air Force doesn't do it and the FAA doesn't do it because it is a pointless waste of effort. This NASA report is astoundingly ludicrous. Columbia's wing came off in a region of the envelope that was *way* outside of anywhere that was known to be survivable. Why would anyone need a separate standalone report detailing how the crew died? Published almost 6! years after the fact, no less. What's next, NASA? How bout a timely 500 page analysis on exactly how Geoffrey de Havilland died. Inquiring minds NEED to know! Be sure to include the serial number of the panel that initially entered his left temporal lobe, as well as all other pieces of hardware that had the potential to become lodged into his cranium. Do the simulated analysis of the forward cockpit dynamics as his jet disintegrated. Then cite the intriguing fact that even if his body had not become impaled, then he would have flailed to death by q-bar loads. And if he had not become impaled or flailed to death, then he would have died by drinking in the Thames. How is it that we've gone over 60 years without this crucial study being funded with millions of taxpayer dollars and the findings made public (so his family can soak in the juicy details too)? For STS-107, the crew had no hope of survival. SCSIIT asks, "What events occurred that had lethal potential for the crew, even after the crew became deceased?" How's this for a major epiphany... If you don't design your spacecraft with any way for your crew to survive a huge range of mishaps, when those mishaps occur then the crew is expected to die. So what was NASA trying to accomplish by burning all those boot soles? Shuttle forebody dynamics simulation using Apollo capsule damping moments?! With this embarrassing report, NASA has hit an all- time low. How ironic for this to be released at the 40th anniversary of one of the greatest accomplishments that NASA (or the human race at large) ever did. I will not be surprised if Obama pushes to dismantle NASA because of its current state of buffoonery, exemplified by this "Crew Survival" report. ~ CT |
#12
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New Columbia loss report out today
On Tue, 30 Dec 2008 20:11:48 -0600, Pat Flannery
wrote: Okay, I'm in 166 pages so far... and _this_ is interesting. The fact that the titanium would actually _burn_ and not just melt was very unexpected. ....Which begs explanation of just how much high velocity heat testing has been done to titanium alloys prior to the Shuttle, especially with some of the reentry body concepts such as ASSET. OM -- ]=====================================[ ] OMBlog - http://www.io.com/~o_m/omworld [ ] Let's face it: Sometimes you *need* [ ] an obnoxious opinion in your day! [ ]=====================================[ |
#13
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New Columbia loss report out today
Pat Flannery wrote: Okay, I'm in 166 pages so far... and _this_ is interesting. The fact that the titanium would actually _burn_ and not just melt was very unexpected. But the recovered titanium parts showed far more damage than they should have from simple heating during the failed reentry. Burning was due to either severe oxidation in the hot air and plasma generated by the reentry, shock wave impingment, or some combo of both. What makes that interesting is that the Lockheed VentureStar SSTO was supposed to use lightweight titanium tiles on its underside as a TPS during reentry. This indicates that that concept may not be workable, and it may have been lucky that the X-33 got canceled when it did... before being converted into a full-scale operational vehicle that would probably fail during its first reentry. I've now finished going through the report looking for things of interest, and found another one involving titanium. Located on the upper forward wall of the cargo bay (the bulkhead with the two windows looking back into the cargo bay and the airlock hatch) are titanium rollers that the front edge of the cargo bay doors move on when they are being opened or closed. One of the parts of Columbia that was recovered was a fragment of one of the two upper fuselage windows that are located directly ahead of the cargo bay doors and allow the astronauts to look straight up out of the top of the orbiter. The fragment showed a very odd feature in regards to its burn damage; it had three distinct layers of deposits on it. Closest to the surface was a layer of deposited titanium, then a layer of mixed titanium/aluminum deposits, then finally a layer of mainly aluminum deposits. This indicates that first it was hit with titanium vapor, then titanium and aluminum, then mainly aluminum as it continued to experience heating during its descent after vehicle break-up. The closest source of titanium were the two roller wheels, which were mounted on a aluminum frame. That suggests that the titanium started to either burn _before_ the aluminum in the same area did, which is counter-intuitive given the high heat resistance of titanium compared to aluminum. But there's a big variable here...the effect of heat on titanium and aluminum is based on information on how it behaves when heated in the mix of gases that are found in the Earth's surface atmosphere and at surface pressures. As the report mentions, when the vehicle was breaking up it was at very high altitude and low atmospheric pressures, and two of the main components of _that_ atmosphere are oxygen and atomic oxygen (ozone). And it looks like titanium when heated and brought into contact with that sort of gas mixture may behave way differently than it does on the ground, including starting to ignite, or at least severely oxidize, at fairly low temperatures - below those that aluminum burns at under the same conditions. Pat |
#14
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New Columbia loss report out today
On Tue, 30 Dec 2008 16:19:06 -0600, Pat Flannery
wrote: M wrote: The official 400 page report in PDF format is he http://www.nasa.gov/pdf/298870main_SP-2008-565.pdf It is the most detail accident report I have ever read in my life. I had access to Air Force accident reports while I was in the service, and I read AW&ST accident reports on airline accidents. This report is very very detailed. It's also 16.3 megabytes in size for anyone who downloads it, so be forewarned. I haven't read it yet, but even the table of contents gives some clue as to the degree of detail it goes into, with investigations of the effects of thermal heating on the soles of the astronaut's boots. One section of the report may lead to a change in space suit design; according to the report the non-form-fitting shape of the space helmets led to the astronaut's heads violently impacting the interior of the helmets as their bodies were flailed around after their upper body restraints failed to lock into place as they were supposed to do when g loads became excessive, so it might be time to either put more padding in the helmet or come up with a soft inflatable type helmet. The pressure suit helmet the Russians use on the Sokol-KV2 space suit during Soyuz ascent and reentry is partially inflatable, as it was on the G5C suits used on the Gemini 7 flight. One thing you could do is rigidly mount a padded helmet to the top of the pressure suit so that it could be rotated around its neck ring, but would keep the astronaut's head from moving around inside the helmet except in rotation. IIRC, aren't they using something like this already on race cars to prevent broken necks in crashes? Pat, You're thinking of the HANS (Head And Neck Support) device, I presume. For those not familiar with it, one strap on each side of the helmet fastens to the back of the device, which sits on the driver's shoulders. The whole thing is held down and in place by the shoulder harness, which comes over each shoulder and is fastened (with the seat belts) right at the driver's waist. It doesn't prevent movement of the head--rather, it prevents excessive movement of the head in an accident. IOW, you can still move your head in all directions, it just prevents your head from moving so far from your body that you suffer a basilar skull fracture (basically, your skull gets disconnected from your spinal column). I'm thinking it might be tough to get the straps tight enough to prevent hitting the inside of the "outer" helmet too hard, but still leave enough flexibility for the astronaut to move his or her head as needed. Plus, the HANS works because it is kept very tight against the body by the shoulder harness (and I've known several race drivers who wore their belts so tight they left bruises even without being in an accident). You'd almost have to have something _inside_ the suit to keep it in place and strapped down to the shoulders (if it's not strapped down, moving your head would just lift it off your shoulders). I don't know, but if I had to SWAG, I'd guess that there is too much possible movement of the body inside the suit for the suit to hold it down. If it's doable, though, I vote for a "hard shell" version of the Snoopy cap. take care, Scott |
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New Columbia loss report out today
On Dec 30, 3:19 pm, Pat Flannery wrote:
I haven't read it yet, but even the table of contents gives some clue as to the degree of detail it goes into, with investigations of the effects of thermal heating on the soles of the astronaut's boots. Then there's this bit, which I discuss slightly he http://up-ship.com/blog/?p=1570 " The hold-down cables on each neck ring were severed at the attach points to the cable guide tubes due to mechanical overload (figure 3.2-24). Most cable guide tubes experienced significant plastic deformation. The guide tubes display evidence of external contaminants (i.e., melted metal and suit material) and thermal effects on top of the fractures and localized deformation. This indicates that mechanical loading preceded exposure to the thermal environment. Rotation of the helmet relative to the normal forward position was observed on all neck rings varying from 90 to 180 degrees. Major cable guide tube deformation and helmet rotation indicates that a significant loading event occurred where helmets were removed via a mechanical (nonthermal) mechanism. " The helmets were twisted off of the suits. While described clinically, it reads like a horror story. |
#16
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New Columbia loss report out today
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#17
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New Columbia loss report out today
Matt wrote: Why was there not, in the original design, or at least in the post- Challenger mods when they added the ACES suit and the bailout system, an air supply (say, a 60-minute bottle mounted on each seat) adequate to have everyone sealed in pressure suits throughout the reentry procedure? Crewmembers would still have their PEAPs as an emergency backup. They pointed out the problem with the suits and the onboard oxygen system in the report. When the suits are buttoned up and pressurized, the exhaled air enters the crew module. Since this is a pure oxygen pressurization system and the exhaled air still has a lot of oxygen in it, the cabin oxygen content starts to climb, leading to a fire hazard. That's why the astronauts do their reentry with their visors up, and are only to lower them in the event of trouble. At least some of them did a suit pressurization test prior to reentry, but then raised their visors again and went back to cabin air. Of course pressurizing your suit isn't going to work if you don't have your gloves on, so that was a major slip-up in regards to crew safety, in that three of them didn't have their gloves on when things started to go wrong (as well as one not having their helmet on); it also brings up a possible design problem - when the Shuttle was designed the intention was to have the crew fly without pressure suits...i.e. no gloves. Are the switches and buttons on the control panel too small to be easily manipulated while you are wearing pressure suit gloves? Pat |
#18
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New Columbia loss report out today
Matt wrote: The folks who did this report and the CAIB and Challenger ones are infinitely more qualified than I am, but I just don't get why this was not, at the least, a post-Columbia mod. I'm still trying to figure out the oxygen in cabin fire hazard part... if they only went over to suit oxygen when they first started to interface with the atmosphere and back to cabin air once they had decelerated to under, say, Mach 2...then one wouldn't think there would be enough time for a excessive oxygen situation to develop, as this all takes under half an hour. Pat |
#19
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New Columbia loss report out today
Stuf4 wrote:
From M : http://www.nasa.gov/pdf/298870main_SP-2008-565.pdf It is the most detail accident report I have ever read in my life. I had access to Air Force accident reports while I was in the service, and I read AW&ST accident reports on airline accidents. This report is very very detailed. The Air Force doesn't do it and the FAA doesn't do it because it is a pointless waste of effort. This NASA report is astoundingly ludicrous. Columbia's wing came off in a region of the envelope that was *way* outside of anywhere that was known to be survivable. Why would anyone need a separate standalone report detailing how the crew died? Published almost 6! years after the fact, no less. What's next, NASA? How bout a timely 500 page analysis on exactly how Geoffrey de Havilland died. Inquiring minds NEED to know! Be sure to include the serial number of the panel that initially entered his left temporal lobe, as well as all other pieces of hardware that had the potential to become lodged into his cranium. Do the simulated analysis of the forward cockpit dynamics as his jet disintegrated. Then cite the intriguing fact that even if his body had not become impaled, then he would have flailed to death by q-bar loads. And if he had not become impaled or flailed to death, then he would have died by drinking in the Thames. How is it that we've gone over 60 years without this crucial study being funded with millions of taxpayer dollars and the findings made public (so his family can soak in the juicy details too)? For STS-107, the crew had no hope of survival. SCSIIT asks, "What events occurred that had lethal potential for the crew, even after the crew became deceased?" How's this for a major epiphany... If you don't design your spacecraft with any way for your crew to survive a huge range of mishaps, when those mishaps occur then the crew is expected to die. So what was NASA trying to accomplish by burning all those boot soles? Shuttle forebody dynamics simulation using Apollo capsule damping moments?! With this embarrassing report, NASA has hit an all- time low. How ironic for this to be released at the 40th anniversary of one of the greatest accomplishments that NASA (or the human race at large) ever did. I will not be surprised if Obama pushes to dismantle NASA because of its current state of buffoonery, exemplified by this "Crew Survival" report. Your being a bit harsh aren't you. The report is the culmination of years of work by what is probably a relatively small group of people. The purpose of the report is to improve the state of the art. Although NASA has chosen to take the Space Program backwards, back to the 60s, with a remake of Apollo, improvements can be made. It's a nice detailed report, maybe I'll read the entire report. But, to me, it looks like for some future vehicle's occupants might survive such a breakup. Haven't read the specific recommendation yet, but what I've gathered so far... The bubble helmets aren't good ascent/entry helmets. The "non" conformal bit. They should be more like crash helmets, NASCAR comes to mind, a helmet that fits snuggly and protects the head from impacts as well as maintaining pressure. Helmets that move with the head. Another, manual closure of the helmets didn't work. A pressure sensing, automated visor/pressurization safety system would be a good idea. Another, the paracutes didn't work, no pressure sensing deployment. Another, seat belts didn't work, maybe active restraints (not just locking) like an ejection seat that pulls the occupants legs, arms, and in this case shoulders back into the seat. Fully (or mildly) restraining the occupant motion when activated would be a good thing. Making an ascent/entry vehicle crash worthy, to protect the occupants. Again, NASCAR comes to mind and they are way ahead of NASA in many respects. The car is designed to come apart protecting the occupant, reducing the loads all along the way, during the crash. Something that could be incorporated in a future design. Although unintended in it's design, this happened when the crew compartment separated from the fuselage. 3 gees down to 1 gee. Designing it structurally and aerodynamically to continue coming apart around the occupants would keep the force loads down, just like a NASCAR car. Aerodynamic bucket seats, like a NASCAR roll cage, the most structural part surrounding the occupant. Designed to fly right, if ever thrown out into the slipstream. Graphite/Epoxy, High temperature conformal foam/insulation, The titanium tub of the A-10 that someone else mentioned. High temperature materials aren't heavy, they're actually probably the materials of choice from a weight perspective, just a bit harder to manufacture. Use titanium or carbon/epoxy liberally around the occupants. Stay away from low temperature materials, like aluminum. Maybe some occupants of some future vehicle will survive such a Disaster that Columbia was. -- Craig Fink Courtesy E-Mail Welcome @ |
#20
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New Columbia loss report out today
Craig Fink wrote:
Making an ascent/entry vehicle crash worthy, to protect the occupants. Again, NASCAR comes to mind and they are way ahead of NASA in many respects. The car is designed to come apart protecting the occupant, reducing the loads all along the way, during the crash. Something that could be incorporated in a future design. Although unintended in it's design, this happened when the crew compartment separated from the fuselage. 3 gees down to 1 gee. Designing it structurally and aerodynamically to continue coming apart around the occupants would keep the force loads down, just like a NASCAR car. In a car accident, you want to protect the occupants by keeping the g forces to a minimum. In an orbital reentry accident, the g forces on the occupants are a secondary issue, not to be ignored completely, but not the main issue. You want the occupants to have breathable air and you don't want them to fry. Keeping the pressure vessel around the occupants intact is a wise choice for a reentry vehicle. Alain Fournier |
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