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New Columbia loss report out today



 
 
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  #41  
Old January 3rd 09, 06:29 PM posted to sci.space.history,sci.space.policy
Stuf4
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Posts: 554
Default 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  
Old January 3rd 09, 10:56 PM posted to sci.space.shuttle,sci.space.policy,sci.space.history
Craig Fink
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Default 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  
Old January 3rd 09, 11:08 PM posted to sci.space.history,sci.space.policy
Craig Fink
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Posts: 1,858
Default 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  
Old January 3rd 09, 11:56 PM posted to sci.space.history
Pat Flannery
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Posts: 18,465
Default 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  
Old January 4th 09, 06:19 AM posted to sci.space.history,sci.space.policy
Pat Flannery
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Default 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  
Old January 4th 09, 10:11 AM posted to sci.space.history
Neil Gerace[_3_]
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Posts: 145
Default 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  
Old January 4th 09, 12:13 PM posted to sci.space.history,sci.space.policy
Craig Fink
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Posts: 1,858
Default 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
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  #48  
Old January 4th 09, 01:18 PM posted to sci.space.history
Craig Fink
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Posts: 1,858
Default 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  
Old January 4th 09, 01:43 PM posted to sci.space.history
Pat Flannery
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Posts: 18,465
Default 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  
Old January 4th 09, 02:01 PM posted to sci.space.history
Pat Flannery
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Posts: 18,465
Default 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
 




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