|
|
Thread Tools | Display Modes |
#41
|
|||
|
|||
New Columbia loss report out today
From Craig Fink:
Here is an intersting video...http://www.popsci.com/node/30347 The aluminum is stripping oxygen from the titanium-dioxide to make titanium metal. Fascinating. And I had no idea that I've been consuming titanium all my life (TiO2 in tootepaste?!). ~ CT |
#42
|
|||
|
|||
New Columbia loss report out today
mJohn Doe wrote:
Craig Fink wrote: I'm sure the passengers on the middeck would have had plenty of information about their situation, starting with the loss of tire pressured discussion. From what I read, it wasn't until loss of APU that thy started to realise something wrong other than faulty sensors was happening. The Commander and Pilot most likely would have noticed the diverging control surface trim as the aerodynamics slowly changed, The report mentions the opposite. Same with the RCS firing continually. There is small light on a button, but apparently, this is not something they focus on. And they would have been focusing on alarms, initially the tire pressure one which was seen as a glitch, then something to worry about because it was more than one faulty sensor, and then the APU failure. In terms of CRM, I a not sure how the PLT/CDR split the tasks under such circumstances. But the report did reveal that they did try to fix the APU problem at a time after loss of communication. Prior to loss of control, the Commander may have asked someone to take a look behind to see if they could see anything in the plasma trail. Is that something they are trained to do ? I would think that what was more likely was that *IF* any of the aft deck crewmembers had had previous experiece and *IF* they noticed unusual plasma over the top windows, that they would then volunteer that information to CDR/PLT. But doubt that the CDR/PLT would distract themseves by asking such a question. between the left and right side. Burning aluminum and disturbed flow, possibly even super bright white flashes as globs of liquid aluminum get instantly dispersed and burn in the slipstream. It is not clear that the "burning aluminium" would have been begun before they lost consciousness. Looks to me that the tiles would have continued to protect the crew module until first breach. This report seems to have pinpointed the location of the first pressure vessel breach, under the E locker below middeck. Until this point, the report mentioned many times that the crew cabin was still very normal and intact. floor. There was quite a bit of time between the first indications of something amiss and loss of control. Not that much time. Initially, they were focused on a glitch (loss of sensors on landing gear). This was something way in the back of the shuttle, not the crew cabin. Losing a tire would have made a bad landing, but woudln't have caused crew cabin depressurisation. By the time they lost radio contact, it really wasn't long until power was lost. And remember that initially, loss of radio was not abnormal since it happens during normal re-entry. Shuttle Surfing during a normal entry, walking around the cabin would be like walking around an airline's cabin, except the gee force would be very small initially, then slowly build. I am not sure NASA would take too kindly if astronauts started to have such a non-chalant attitude during re-entry. And remember that while during this phase, the G forces may be mild, the question is whether the crew member will have time to get properly strapped in before serious G forces are felt. planets, especially the ones on the middeck who normally have nothing to do, and lots of space to do it in. An interesting environment. Middeck of Colubia didn't have lots of space. Remember that Columbia still had the internal airlock. And once you put the seats up, I am not sure there is much floor space left. Much of what I wrote was just pure conjecture. What they knew or didn't, will never be known. If you don't like it, don't believe it, that's fine, because it's conjecture. No one knows if they saw, or heard the yaw jets firing. But, it's something they could have heard or seen before loss of control. No one knows if they noticed the control surfaces (trim) slowly diverging towards there limit. But again, it's something that was there. I somewhat doubt the crew took the tire pressure loss as a sensor error, because they *did* know about the wing impact on ascent. But again, nobody will ever know what they thought of the loss of pressure. Loss of communications occurred quite a bit before loss of control when the APUs went down. I don't think they can see out the top windows when seated???? Maybe they can, or at least turn the camera around... http://www.youtube.com/watch?v=hK1RxQKCmCE ....or use a mirror...notice the debris flying off the crew cabin past the window. Prior to loss of control, the burning aluminum would have been coming from the wing. One camera on the ground was saturated by a bright flash. Such a bright flash might have been a much brighter closer up. Although one or two bright flashes among all the APU flashes might not have been noticed. Prior to loss of control any debris falling off the wing would have create it's own plasma trail visible in the Orbiters plasma trail. Visible out the top windows looking back. As to if anyone *actually* saw any of them, no one will ever know. One astronaut may have been out of his seat, highly unusual as I've only heard of one astronaut Shuttle Surfing. And then again maybe he wasn't, no one will ever know. You know, quite a bit of this report is just conjecture or educated guesses, including some of the simulations, analysis and conclusions. Much of it is reporting of the known fact, but it also continues past the facts into the realm of conjecture. Take it with a grain of salt. What I wrote about was what I thought was available prior to loss of control that might have been observed. I'm sure there may have been other thing that prior to loss of control that might have gotten their attention. But, no one will ever know what they knew. Feel free to write your own fiction posting, if you don't like mine. -- Craig Fink Courtesy E-Mail Welcome @ |
#43
|
|||
|
|||
New Columbia loss report out today
Stuf4 wrote:
From Craig Fink: Here is an intersting video...http://www.popsci.com/node/30347 The aluminum is stripping oxygen from the titanium-dioxide to make titanium metal. Fascinating. And I had no idea that I've been consuming titanium all my life (TiO2 in tootepaste?!). lol, spit it out next time. ;-) It's a great sunscreens too. -- Craig Fink Courtesy E-Mail Welcome @ |
#44
|
|||
|
|||
New Columbia loss report out today
Craig Fink wrote: lol, spit it out next time. ;-) It's a great sunscreens too. And in powdered metal form is used in fireworks: http://chemistry.about.com/od/firewo...taniumfire.htm Titanium has been referred to as "the nymphomaniac of metals" as it "will bond with anything". Putting something like that into contact with superheated oxygen and ozone was bound to lead to interesting results. If nothing else, Columbia taught us that you better never put titanium into contact with reentry plasma, which makes the lightweight titanium TPS intended for the LockMart VentureStar look like a major bad move. Pat |
#45
|
|||
|
|||
New Columbia loss report out today
Jorge R. Frank wrote: 1) Columbia did not carry the RMS on STS-107. Without a payload to drop off and pick up there was no reason to carry the RMS. 2) The CAIB addressed the option of an inspection EVA - without the arm - in Volume 1, Section 6.4, page 173. Which concerns damage to the TPS if a astronaut tries to climb out of the cargo bay and under the wing to have a look at things. However, given where the foam impacted at just under the leading edge of the wing, a astronaut may have been able to see the damage just by peeking past the front edge of the cargo bay doors at what the leading edge of the wing looked like. Considering the concerns that NASA had shown in the past after things like chipped tiles on ascent from popcorning of the foam, it's very surprising that they didn't at least okay a EVA of even that limited extent after seeing the obviously major foam impact event during ascent. In fact, the whole reason the ET ended up with that ascent video camera on its exterior was to record foam shedding events that were causing unexpected damage to the tiles during ascent, and IIRC that was first flown two flight before the loss of Columbia Even more surprising is that they didn't okay a look at Columbia from a reconsat; that would have completely removed any sort of safety risk from a EVA, and frankly I find the argument that nothing could be seen if the impact had occurred where it was thought to have occurred - ahead of the port landing gear door - unconvincing, considering that once the black exterior surface of the densified belly tiles was abraded away the white interior of the tiles would be revealed, giving a almost perfect optical contrast for detection. Pat |
#46
|
|||
|
|||
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. Titanium is in fact one of the more reactive metals. It can be used as a structural metal (unlike e.g. sodium) because any cut face reacts quickly with atmospheric oxygen. The oxide layer is tightly bound to the metal underneath. This prevents oxygen from further attacking the metal. Same thing happens with aluminium. It also happens with iron, but in that case the oxide doesn't bond very strongly with the metal, allowing oxygen to further corrode it. |
#47
|
|||
|
|||
New Columbia loss report out today
Pat Flannery wrote:
Craig Fink wrote: Interesting x-link discussion, page 2-37 through 2-45, looks like Titanium performed well and it didn't. It caught fire too, along with all the aluminum. (the aluminum fire seems to be absent from the discussion)... http://www.nasa.gov/pdf/298870main_SP-2008-565.pdf What's interesting is that the titanium caught fire _before_ the aluminum did based on the deposits on the recovered fragment of the top window. Yeah, it's interesting. It Burns like a piece of wood. One of the other interesting failure was in some of the seat structure, "broom-straw" fractures 3.1-16. Aluminum is a good conductor of heat, but it also has a huge thermal expansion coefficient. I haven't seen a "broom-straw" fracture before. Seems that Aluminum 7075 is a laminate material. -- Craig Fink Courtesy E-Mail Welctome @ |
#48
|
|||
|
|||
New Columbia loss report out today
Pat Flannery wrote:
Craig Fink wrote: lol, spit it out next time. ;-) It's a great sunscreens too. And in powdered metal form is used in fireworks: http://chemistry.about.com/od/firewo...taniumfire.htm Titanium has been referred to as "the nymphomaniac of metals" as it "will bond with anything". Putting something like that into contact with superheated oxygen and ozone was bound to lead to interesting results. If nothing else, Columbia taught us that you better never put titanium into contact with reentry plasma, which makes the lightweight titanium TPS intended for the LockMart VentureStar look like a major bad move. Without a coating, seems it would be. Carbon (as in the Orbiter's nose cap) burns as a solid too, just like the titanium. I think the leason of Columbia points to an all composite vehicle, glass or a carbon/silicon carbide mix for all the structure around the occupants. Maybe some titanium or aluminum in the right places to control the breakup of the vehicle in an accident, weakest links at high temperatures. The helmets were interesting, really survived quite well. The outer layer debonded and resin burned, but the layer of glass remained and protected the rest of the layers. A pure carbon (as in graphite) might burn, but add a little silicon carbide fiber to the mix, or outer layer entirely out of silicon carbide, or a resin with a glass/silicon carbide filler. Now the thin panels protecting the occupants, that were never intended to meet the plasma, can glow all they want. A resin with several different types of glass filler might work really well. As the resin burns, the filler melts coating the fibers, at higher temperatures more of the filler melts... Also, i don't think they went far enough to stress protecting the occupants against tumbling gee forces. They seem to stress the head and neck. The seats need to wrap around more like a NASCAR roll cage, or graphite tub. -- Craig Fink Courtesy E-Mail Welcome @ |
#49
|
|||
|
|||
New Columbia loss report out today
Neil Gerace wrote: 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. Titanium is in fact one of the more reactive metals. It can be used as a structural metal (unlike e.g. sodium) because any cut face reacts quickly with atmospheric oxygen. The oxide layer is tightly bound to the metal underneath. This prevents oxygen from further attacking the metal. Same thing happens with aluminium. It also happens with iron, but in that case the oxide doesn't bond very strongly with the metal, allowing oxygen to further corrode it. Check up on my later posting regrading when the aluminum versus titanium ignited when the Columbia orbiter broke apart. Surprisingly, it was the titanium, not aluminum, that first ignited after the whole orbiter first started going to pieces. Pat |
#50
|
|||
|
|||
New Columbia loss report out today
Craig Fink wrote: One of the other interesting failure was in some of the seat structure, "broom-straw" fractures 3.1-16. Aluminum is a good conductor of heat, but it also has a huge thermal expansion coefficient. I haven't seen a "broom-straw" fracture before. Seems that Aluminum 7075 is a laminate material. That's one of the_really_ strange photos in the report, isn't it? You would think that the aluminum frames of the chair supports would have been a lot more homogeneous than shown; particularly in regards to their internal microscopic structure. Pat |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Followup [FAQ] Minor notice Columbia Loss FAQ | dave schneider | Space Science Misc | 1 | July 10th 04 05:58 PM |
[FAQ] Minor notice Columbia Loss FAQ | OM | Space Shuttle | 2 | July 9th 04 06:16 PM |
[FAQ] Minor notice Columbia Loss FAQ | OM | Policy | 2 | July 9th 04 06:16 PM |
[FAQ] Minor notice Columbia Loss FAQ | OM | History | 2 | July 9th 04 06:16 PM |