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New Columbia loss report out today



 
 
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  #11  
Old December 31st 08, 04:32 AM posted to sci.space.history,sci.space.policy
Stuf4
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Posts: 554
Default 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  
Old December 31st 08, 04:54 AM posted to sci.space.history
OM[_6_]
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Default 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  
Old December 31st 08, 05:20 AM posted to sci.space.history,sci.space.policy
Pat Flannery
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Posts: 18,465
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.
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  
Old December 31st 08, 06:21 AM posted to sci.space.history,sci.space.policy
Scott Stevenson
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Posts: 67
Default 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

  #15  
Old December 31st 08, 09:24 AM posted to sci.space.history,sci.space.policy
[email protected]
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Posts: 270
Default 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  
Old December 31st 08, 12:50 PM posted to sci.space.history,sci.space.policy
Pat Flannery
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Posts: 18,465
Default New Columbia loss report out today



wrote:
The helmets were twisted off of the suits. While described clinically,
it reads like a horror story.

The report states that one reason the helmets were twisted off was
increased air drag due to having the visors open.
The photos of the suit remnants are pretty disturbing also...things like
neck rings and glove attachment rings survived fairly intact, but
burned. The rest of the suit was basically melted and burned away.
Even the fiberglass helmets were badly burned and their plastic visors
melted and burned away.
They couldn't even simulate a situation that left the shoes as badly
damaged as the recovered ones were. They had basically come apart.
Although the medical section of the report is redacted, if you read
around the redacted sections, you get the impression that the failed
shoulder restraint inertia locks meant the astronauts were possibly torn
apart at their waists from the bottom part of the body being restrained
by the waist and crotch belts while the top part flailed around.
Whatever happened to them caused fatal injuries from the effects on the
body of the waist and crotch belts according to the report.
It's probably pretty merciful that they were either unconscious or dead
before this all happened due to the loss of cabin pressure.
One thing that hit me as odd was how the Shuttle is shifted from
autopilot to manual control during descent...merely moving either of the
control sticks will drop out the autopilot, and it has to be returned to
control via a reset of its computer systems.
On the final Columbia mission one of the control sticks got accidentally
bumped prior to atmospheric interface and switched it into manual mode,
so it had to be reset.
If that had happened during a critical section of reentry, you could
have a busy few seconds before you could get it back on autopilot.
That's just asking for trouble; autopilot should be disengaged by
grabbing the control stick _and pressing some sort of switch on it_ like
the firing button on a fighter joystick.

Pat


  #17  
Old December 31st 08, 01:12 PM posted to sci.space.history,sci.space.policy
Pat Flannery
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Posts: 18,465
Default 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  
Old December 31st 08, 01:24 PM posted to sci.space.history,sci.space.policy
Pat Flannery
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Posts: 18,465
Default 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  
Old December 31st 08, 03:32 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 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  
Old December 31st 08, 06:57 PM posted to sci.space.history,sci.space.policy
Alain Fournier[_2_]
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Posts: 373
Default 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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