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The Space Race was about Power Projection - Miles O'Brien



 
 
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  #61  
Old February 4th 17, 05:10 PM posted to sci.space.history
Jeff Findley[_6_]
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Posts: 2,307
Default The Space Race was about Power Projection - Miles O'Brien

In article ,
says...
Stuf4 wrote:
The Air Force has a program called "ABDR" that teaches how to do
such repairs. They will cut things like soda cans and flatten
them out and then duct tape them onto holes on a jet's wing or
fuselage as a viable patch.


You're talking about temporary repairs to bullet holes in flat pieces
of non-critical structure merely in order to smooth airflow, which is
just a little bit different than trying to replace a high temperature
piece of the TPS with a bit of tin can and speed tape. You can't fix
leading edge damage on ordinary aircraft like that, so you certainly
can't fix hypersonics with it.


So for doing a MacGyver-style Aircraft Battle Damage Repair of
Columbia's wing leading edge, you scour the crew cabin for some
flat bendable piece of metal. Maybe use clipboards. Whatever.
Then go out and tape it over the gaping hole. On day of Entry,
hope it holds long enough to get you home.


It won't. The first heat pulse will make it go away as if it wasn't
even there. When the experts started looking for a way to deal with
this type of damage after the accident, they came to the conclusion
that there was no way to implement an on-orbit repair.


As for detecting the damage, they could either have used NRO spy
sats, or simply get out and look. Such an EVA could have been
done on Flight Day 2.


They wouldn't have been looking in the right place for the right
thing. They were looking for TPS tile damage near the leading edge,
which is why they thought it was an acceptable risk. Nobody believed
that a piece of foam would be a sufficient impact to damage the RCC.



Fred is spot on with every point. And do keep in mind that after
Columbia the engineers had essentially unlimited time to come up with a
"glove" to bolt over leading wing edge damage. Even with the "right"
materials, it really wasn't possible to make such a repair without
wrecking the leading edge aerodynamics. If memory serves, during
reentry this would create hot spots which would likely burn through
which kind of defeats the purpose of a repair.

For tile damage (not RCC damage), a repair kit was developed (reference
below). But, the best NASA could do for wing leading edge damage like
Columbia had would have been to leave the crew to "shelter" on ISS for
rescue by another shuttle.

For the damaged orbiter, the astronauts would install "jumper wires" on
the badly damaged orbiter so it could be flown remotely towards a
landing (in the case where the damage could be repaired) or towards a
destructive reentry in the case where the damage was too great to repair
(i.e. RCC damage). The "jumper wires" were required because the orbiter
design included a few buttons which an astronaut had to physically push
and it therefore could not be flown remotely from deorbit to landing.
Reference:

http://www.space.com/2560-shuttle-ca...emote-control-
landing.html

For the last Hubble repair mission, I believe they had another shuttle
nearly ready to launch a rescue mission since "sheltering" at ISS
wouldn't have been an option. Searching... Yep, here's a reference:

https://www.wired.com/2014/12/sts-125-hubble-mission/

From above article:

Shuttle flights resumed in 2005, with the requirement that every
shuttle have its heat shields checked at the International Space
Station before reentry. But that wasn't an option for STS-125.
The orbit needed to rendezvous with Hubble wouldn't allow a visit
to the space station.

Instead, Endeavour was placed on standby, ready to launch should
Atlantis be unable to return. And the crew would have to inspect
its own ship. NASA had a plan for that, too?the Orbiter Boom
Sensor System, a 100-foot arm fitted with a camera, a laser and
other equipment. It was first deployed on STS-114, the inaugural
flight after Columbia. Once STS-125 was in orbit, mission
commander Scott Altman would deploy it to check Atlantis for
launch-related damage to the heat shields.

Stuf4, all of these details were covered by the "space media" and is
available online thanks to the magic of the Internet. You just have to
do a few Google searches to find it. It's all quite fascinating history
at this point (since the shuttles are quite literally museum pieces).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #62  
Old February 4th 17, 07:38 PM posted to sci.space.history
Scott M. Kozel[_2_]
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Posts: 160
Default The Space Race was about Power Projection - Miles O'Brien

On Saturday, February 4, 2017 at 10:42:55 AM UTC-5, Jeff Findley wrote:
In article ,
says...

Scott Kozel wrote:
Columbia could have been saved; if they used ground based telescopes to find the damage, then they would have had 2 weeks to come up with a patch from either material on board or material sent up on an expendable rocket, then EVAs to apply the patch. The ability to patch would have been marginal, but they would have had a good shot at a safe landing.


Do you understand what was damaged on Columbia? I don't think you
could have seen it with a ground based telescope and even if you could
the Shuttle would have been a write off because there was no way to
effect a repair on orbit. There's no way to 'patch' that kind of
damage.


No way? Au contraire. It is quite possible that *duct tape* might have gotten them home.

The Air Force has a program called "ABDR" that teaches how to do such repairs. They will cut things like soda cans and flatten them out and then duct tape them onto holes on a jet's wing or fuselage as a viable patch.

So for doing a MacGyver-style Aircraft Battle Damage Repair of Columbia's wing leading edge, you scour the crew cabin for some flat bendable piece of metal. Maybe use clipboards. Whatever. Then go out and tape it over the gaping hole. On day of Entry, hope it holds long enough to get you home.


Wrong. The wing leading edge was reinforced carbon-carbon composite.
This was the material on the shuttle which could withstand the most
reentry heating. This isn't something you can "MacGyver" with any spare
parts on board Columbia.


That depends on the exact nature of the damage, and given that it wasn't
surveyed by EVA or by shuttle-based camera or by telescope, we don't know
whether it was a big hole or a small hole, or whether it was on the
leading edge or behind of there. That could not be ascertained after the
fact from the debris on the ground.

Sending another shuttle on a rescue or repair mission would have had its
own risks to that vehicle and crew, so that would need to be considered
carefully before making that decision.

That is why I suggested sending an expendable rocket with materials to
for Columbia crew to make an emergency patch. Titanium sheets and
sheets of ablative material and fasteners, for example.

As far as to whether an emergency patch would work well enough to at
least make a normal landing, NASA investigators determined that on-orbit
repair by the shuttle astronauts was possible but overall considered high
risk, primarily due to the uncertain resiliency of the repair using
available materials and the anticipated high risk of doing additional
damage to the Orbiter.

And again, that would depend on the exact nature of the damage, and that
is unknown due to the fact that they never made any attempt to examine it.
The smaller the hole the higher the chance of a successful emergency
repair. A huge hole might be impossible.

The problem is that they could have known the nature of the damage on
day 2 of a 14-day flight, but there was never any effort to determine the
nature of the damage let alone try to repair it or come to a conclusion
about whether or not it could be repaired.

Saying stuff like, "Well given issues in the STS there was bound to be
a disaster sooner or later" is not an acceptable conclusion, IMHO.
Never the case in aviation or aerospace.

Yes there are risks in flying 120+ STS missions, but on this particular
mission there could have been a much better outcome, but they didn't even
-try- to assess the damage let alone make a decision about what to do
about it. That is what I meant by this mission being a management failure
and not a purely technological failure.
  #63  
Old February 4th 17, 08:54 PM posted to sci.space.history
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default The Space Race was about Power Projection - Miles O'Brien

In article ,
says...
Wrong. The wing leading edge was reinforced carbon-carbon composite.
This was the material on the shuttle which could withstand the most
reentry heating. This isn't something you can "MacGyver" with any spare
parts on board Columbia.


That depends on the exact nature of the damage, and given that it wasn't
surveyed by EVA or by shuttle-based camera or by telescope, we don't know
whether it was a big hole or a small hole, or whether it was on the
leading edge or behind of there. That could not be ascertained after the
fact from the debris on the ground.


True there was no direct evidence. But, based on camera video the size
of the chunk and its velocity when it hit the wing leading edge was
estimated. So, a ground test was performed which was quite shocking in
the size of the hole it created. From Wikipedia:

As demonstrated by ground experiments conducted by the Columbia
Accident Investigation Board, this likely created a 6-to-10-inch
(15 to 25 cm) diameter hole, allowing hot gases to enter the wing
when Columbia later re-entered the atmosphere.

That's a huge hole when you consider the aerodynamic heating at
hypersonic speeds encountered during reentry.

Sending another shuttle on a rescue or repair mission would have had its
own risks to that vehicle and crew, so that would need to be considered
carefully before making that decision.


So? Make it an all volunteer crew (you'd only need a minimal crew
anyway to make room for the crew being rescued).

Besides, rescue crews of all sorts are quite often at higher risk than
when performing training. When you're trying to save someone's life,
many people will take that risk. Considering many of them came to NASA
from the military, I'd wager that you'd far more volunteers than you'd
need.

That is why I suggested sending an expendable rocket with materials to
for Columbia crew to make an emergency patch. Titanium sheets and
sheets of ablative material and fasteners, for example.


But that quite simply would not work for the RCC wing leading edge. The
best NASA could do was make a repair kit for the tiles.

As far as to whether an emergency patch would work well enough to at
least make a normal landing, NASA investigators determined that on-orbit
repair by the shuttle astronauts was possible but overall considered high
risk, primarily due to the uncertain resiliency of the repair using
available materials and the anticipated high risk of doing additional
damage to the Orbiter.


Almost certainly such a "repair" would have been higher risk than
mounting a rescue mission. Again, rescue crews routinely risk their own
lives. This wouldn't have been any different.

And again, that would depend on the exact nature of the damage, and that
is unknown due to the fact that they never made any attempt to examine it.
The smaller the hole the higher the chance of a successful emergency
repair. A huge hole might be impossible.


A huge hole was quite likely based on the data gathered and the ground
tests performed after the fact. The results shocked pretty much
everyone, because they all assumed that the RCC was "tougher" than the
silica tiles. Everyone was wrong.

The problem is that they could have known the nature of the damage on
day 2 of a 14-day flight, but there was never any effort to determine the
nature of the damage let alone try to repair it or come to a conclusion
about whether or not it could be repaired.


Agreed. The decision to not even attempt look for damage was a bad one,
especially in hindsight.

Saying stuff like, "Well given issues in the STS there was bound to be
a disaster sooner or later" is not an acceptable conclusion, IMHO.
Never the case in aviation or aerospace.


It may not be acceptable to you, but it's the facts. Spaceflight is
inherently risky and we really don't have enough experience doing it yet
to make it much safer than what it was "in the early days". This is
doubly true when SLS is going back to throwing away entire launch
vehicles instead of recovering parts of them for inspection and
refurbishment. It's triply true because SLS will be using five segment
SRBs whose thrust quite simply can't be safely terminated in an
emergency.

Yes there are risks in flying 120+ STS missions, but on this particular
mission there could have been a much better outcome, but they didn't even
-try- to assess the damage let alone make a decision about what to do
about it. That is what I meant by this mission being a management failure
and not a purely technological failure.


Yes, but you can point to the bad decisions made which led up to both
the Challenger disaster and the Columbia disaster. But you have to be
careful you don't fall into the trap of hindsight. Choosing to not fly
on those two days would *not* have eliminated all of the risk. The fact
is that NASA did write too many wavers for its own flight rules during
the shuttle program. Any one of those dodgey systems could have killed
the crew, which is why so many of those systems were improved post
Challenger and even post Columbia.

Hell, even the venerable Saturn V with its "perfect" flight record was a
hair's width away from disaster on at least one flight. Go read up on
the terrifying reality of the POGO problems it had and how close one
flight came to tearing itself apart. Did NASA get away with it?
Certainly. Could they have been more safety conscious with testing the
Saturn V instead of putting crews on top of what amounted to a launch
vehicle that still had issues? Absolutely. But we were in the Space
Race with the Soviet Union and everyone accepted the risk, even the
astronauts.

Anyone who wants perfect safety before they fly will never fly.
Luckily, there is no shortage of people willing to take the risk in an
attempt to attain the rewards.

"As safe as possible" is always a compromise.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #64  
Old February 5th 17, 01:00 AM posted to sci.space.history
Scott M. Kozel[_2_]
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Posts: 160
Default The Space Race was about Power Projection - Miles O'Brien

On Saturday, February 4, 2017 at 2:54:34 PM UTC-5, Jeff Findley wrote:
In article ,
says...
Wrong. The wing leading edge was reinforced carbon-carbon composite.
This was the material on the shuttle which could withstand the most
reentry heating. This isn't something you can "MacGyver" with any spare
parts on board Columbia.


That depends on the exact nature of the damage, and given that it wasn't
surveyed by EVA or by shuttle-based camera or by telescope, we don't know
whether it was a big hole or a small hole, or whether it was on the
leading edge or behind of there. That could not be ascertained after the
fact from the debris on the ground.


True there was no direct evidence. But, based on camera video the size
of the chunk and its velocity when it hit the wing leading edge was
estimated. So, a ground test was performed which was quite shocking in
the size of the hole it created. From Wikipedia:

As demonstrated by ground experiments conducted by the Columbia
Accident Investigation Board, this likely created a 6-to-10-inch
(15 to 25 cm) diameter hole, allowing hot gases to enter the wing
when Columbia later re-entered the atmosphere.

That's a huge hole when you consider the aerodynamic heating at
hypersonic speeds encountered during reentry.


It is still unknown how large the hole was and whether it was
on the leading edge, or rearward where it would have considerably
lower reentry temperatures.

Also the nature of the damage, was there enough internal structure
to support a patch or was that severely damaged? We don't know
because nobody looked.

If they did an EVA or had a Canadarm with a remote camera, they
could have made a very accurate assessment of whether it was
repairable, and on day 2.

If clearly unrepairable, then a rescue mission would be the only
way to rescue the crew. They would have another 12 days to mount
that.

Sending another shuttle on a rescue or repair mission would have had its
own risks to that vehicle and crew, so that would need to be considered
carefully before making that decision.


So? Make it an all volunteer crew (you'd only need a minimal crew
anyway to make room for the crew being rescued).

Besides, rescue crews of all sorts are quite often at higher risk than
when performing training. When you're trying to save someone's life,
many people will take that risk. Considering many of them came to NASA
from the military, I'd wager that you'd far more volunteers than you'd
need.


I mentioned the vehicle as well, you have one in orbit that may
already be lost, and then a second one that you are rushing to
launch. If the rescue mission meets disaster then the one in orbit
doesn't get rescued, the fleet drops from four orbiters down to
two orbiters, and at Endeavour's 1992 cost we're looking at least
$3 billion per orbiter to replace the two that were just lost,
and NASA will have a very difficult time finding that kind of
funding. If the fleet stays at two orbiters then its functionality
is rather limited.

Plus the STS rescue mission will cost the typical $500+ million.

That is why I suggested sending an expendable rocket with materials to
for Columbia crew to make an emergency patch. Titanium sheets and
sheets of ablative material and fasteners, for example.


But that quite simply would not work for the RCC wing leading edge. The
best NASA could do was make a repair kit for the tiles.


Again, they didn't know whether it was the leading edge or the exact
nature of the damage. The expendable rocket could send up several tons of various materials, using whatever was deemed necessary.

As far as to whether an emergency patch would work well enough to at
least make a normal landing, NASA investigators determined that on-orbit
repair by the shuttle astronauts was possible but overall considered high
risk, primarily due to the uncertain resiliency of the repair using
available materials and the anticipated high risk of doing additional
damage to the Orbiter.


Almost certainly such a "repair" would have been higher risk than
mounting a rescue mission. Again, rescue crews routinely risk their own
lives. This wouldn't have been any different.


They had no chance of surviving with the current damage. Repairing
or attempting repairing would not have increased risk on a 0% chance
of survival. Using an expendable rocket would not have risked human
lives and it would have been far less expensive than a shuttle mission.

Again, a damage assessment could have determined whether it was
repairable.

....
I have no disagreement with the remainder that was snipped, I agree
that spaceflight is inherently risky, and about how Apollo/Saturn V
was fortunate that no lives were lost. I fully accept the fact that
it is risky and that disasters can occur.

I just find it regrettable in how Columbia was lost, more on the basis
of management failure than any technological failure.
  #65  
Old February 5th 17, 03:28 AM posted to sci.space.history
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default The Space Race was about Power Projection - Miles O'Brien

In article ,
says...

On Saturday, February 4, 2017 at 2:54:34 PM UTC-5, Jeff Findley wrote:
In article ,
says...
Wrong. The wing leading edge was reinforced carbon-carbon composite.
This was the material on the shuttle which could withstand the most
reentry heating. This isn't something you can "MacGyver" with any spare
parts on board Columbia.

That depends on the exact nature of the damage, and given that it wasn't
surveyed by EVA or by shuttle-based camera or by telescope, we don't know
whether it was a big hole or a small hole, or whether it was on the
leading edge or behind of there. That could not be ascertained after the
fact from the debris on the ground.


True there was no direct evidence. But, based on camera video the size
of the chunk and its velocity when it hit the wing leading edge was
estimated. So, a ground test was performed which was quite shocking in
the size of the hole it created. From Wikipedia:

As demonstrated by ground experiments conducted by the Columbia
Accident Investigation Board, this likely created a 6-to-10-inch
(15 to 25 cm) diameter hole, allowing hot gases to enter the wing
when Columbia later re-entered the atmosphere.

That's a huge hole when you consider the aerodynamic heating at
hypersonic speeds encountered during reentry.


It is still unknown how large the hole was and whether it was
on the leading edge, or rearward where it would have considerably
lower reentry temperatures.

Also the nature of the damage, was there enough internal structure
to support a patch or was that severely damaged? We don't know
because nobody looked.


Bad enough it was starting to cause the control system to have trouble
keeping the orbiter straight due to the increased drag on the side with
the hole. You would not have gotten that with a small hole.

See page 73 of the Columbia Accident Investigation Board's report.

https://spaceflight.nasa.gov/shuttle/archives/sts-
107/investigation/CAIB_medres_full.pdf

If they did an EVA or had a Canadarm with a remote camera, they
could have made a very accurate assessment of whether it was
repairable, and on day 2.


I do not believe there was a Canadarm on that mission. EVA to that
location would have been "sporty" for sure but could have confirmed the
location and size of the hole.

If clearly unrepairable, then a rescue mission would be the only
way to rescue the crew. They would have another 12 days to mount
that.


From page 173 of the Columbia Accident Investigation Board's report:

Because the NASA team could not verify that the repairs
would survive even a modified re-entry, the rescue option
had a considerably higher chance of bringing Columbia's crew
back alive.

Sending another shuttle on a rescue or repair mission would have had its
own risks to that vehicle and crew, so that would need to be considered
carefully before making that decision.


So? Make it an all volunteer crew (you'd only need a minimal crew
anyway to make room for the crew being rescued).
Besides, rescue crews of all sorts are quite often at higher risk

than
when performing training. When you're trying to save someone's life,
many people will take that risk. Considering many of them came to NASA
from the military, I'd wager that you'd far more volunteers than you'd
need.


I mentioned the vehicle as well, you have one in orbit that may
already be lost, and then a second one that you are rushing to
launch. If the rescue mission meets disaster then the one in orbit
doesn't get rescued, the fleet drops from four orbiters down to
two orbiters, and at Endeavour's 1992 cost we're looking at least
$3 billion per orbiter to replace the two that were just lost,
and NASA will have a very difficult time finding that kind of
funding. If the fleet stays at two orbiters then its functionality
is rather limited.

Plus the STS rescue mission will cost the typical $500+ million.


From page 173 concerning a rescue mission using Atlantis:

This rescue was considered challenging but feasible. To
succeed, it required problem-free processing of Atlantis
and a flawless launch countdown. If Program managers had
understood the threat that the bipod foam strike posed
and were able to unequivocally determine before Flight
Day Seven that there was potentially catastrophic damage
to the left wing, these repair and rescue plans would most
likely have been developed, and a rescue would have been
conceivable.


Also, there is a heck of a lot of data in the report (mostly in Chapter
3) which led NASA to conclude that yes there was about a 6 inch diameter
hole in the RCC panel(s) on the wing leading edge. This wasn't
speculation or based solely on one test which fired foam at an RCC
panel. It was supported by a lot of data gathered on launch (ground
camera footage), on orbit (detailed radar data of debris which separated
from the orbiter) and during reentry (various sensor failures,
anomalies, and high temperature readings inside the wing).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #66  
Old February 5th 17, 04:15 AM posted to sci.space.history
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default The Space Race was about Power Projection - Miles O'Brien

"Scott M. Kozel" wrote:

On Saturday, February 4, 2017 at 10:42:55 AM UTC-5, Jeff Findley wrote:
In article ,
says...

Scott Kozel wrote:
Columbia could have been saved; if they used ground based telescopes to find the damage, then they would have had 2 weeks to come up with a patch from either material on board or material sent up on an expendable rocket, then EVAs to apply the patch. The ability to patch would have been marginal, but they would have had a good shot at a safe landing.


Do you understand what was damaged on Columbia? I don't think you
could have seen it with a ground based telescope and even if you could
the Shuttle would have been a write off because there was no way to
effect a repair on orbit. There's no way to 'patch' that kind of
damage.

No way? Au contraire. It is quite possible that *duct tape* might have gotten them home.

The Air Force has a program called "ABDR" that teaches how to do such repairs. They will cut things like soda cans and flatten them out and then duct tape them onto holes on a jet's wing or fuselage as a viable patch.

So for doing a MacGyver-style Aircraft Battle Damage Repair of Columbia's wing leading edge, you scour the crew cabin for some flat bendable piece of metal. Maybe use clipboards. Whatever. Then go out and tape it over the gaping hole. On day of Entry, hope it holds long enough to get you home.


Wrong. The wing leading edge was reinforced carbon-carbon composite.
This was the material on the shuttle which could withstand the most
reentry heating. This isn't something you can "MacGyver" with any spare
parts on board Columbia.


That depends on the exact nature of the damage, and given that it wasn't
surveyed by EVA or by shuttle-based camera or by telescope, we don't know
whether it was a big hole or a small hole, or whether it was on the
leading edge or behind of there. That could not be ascertained after the
fact from the debris on the ground.


We know with as much certainty as you can ever know anything. It was
an approximately 12"x12" hole in RCC Panel 8, located toward the root
of the left wing. So what don't you think we know?


Sending another shuttle on a rescue or repair mission would have had its
own risks to that vehicle and crew, so that would need to be considered
carefully before making that decision.


There was no such Shuttle ready for launch, so it's a moot point.


That is why I suggested sending an expendable rocket with materials to
for Columbia crew to make an emergency patch. Titanium sheets and
sheets of ablative material and fasteners, for example.


You suggest that because you don't understand things.


As far as to whether an emergency patch would work well enough to at
least make a normal landing, NASA investigators determined that on-orbit
repair by the shuttle astronauts was possible but overall considered high
risk, primarily due to the uncertain resiliency of the repair using
available materials and the anticipated high risk of doing additional
damage to the Orbiter.


That's true if the damage is to heat tiles. However, the damage was
not to heat tiles. It was to the RCC leading edge.


And again, that would depend on the exact nature of the damage, and that
is unknown due to the fact that they never made any attempt to examine it.
The smaller the hole the higher the chance of a successful emergency
repair. A huge hole might be impossible.


ANY hole in the RCC is impossible.

snip silliness


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
  #67  
Old February 5th 17, 04:26 AM posted to sci.space.history
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default The Space Race was about Power Projection - Miles O'Brien

"Scott M. Kozel" wrote:

On Saturday, February 4, 2017 at 2:54:34 PM UTC-5, Jeff Findley wrote:
In article ,
says...
Wrong. The wing leading edge was reinforced carbon-carbon composite.
This was the material on the shuttle which could withstand the most
reentry heating. This isn't something you can "MacGyver" with any spare
parts on board Columbia.

That depends on the exact nature of the damage, and given that it wasn't
surveyed by EVA or by shuttle-based camera or by telescope, we don't know
whether it was a big hole or a small hole, or whether it was on the
leading edge or behind of there. That could not be ascertained after the
fact from the debris on the ground.


True there was no direct evidence. But, based on camera video the size
of the chunk and its velocity when it hit the wing leading edge was
estimated. So, a ground test was performed which was quite shocking in
the size of the hole it created. From Wikipedia:

As demonstrated by ground experiments conducted by the Columbia
Accident Investigation Board, this likely created a 6-to-10-inch
(15 to 25 cm) diameter hole, allowing hot gases to enter the wing
when Columbia later re-entered the atmosphere.

That's a huge hole when you consider the aerodynamic heating at
hypersonic speeds encountered during reentry.


It is still unknown how large the hole was and whether it was
on the leading edge, or rearward where it would have considerably
lower reentry temperatures.


They're pretty damned sure they tracked the departing piece of the RCC
during reentry. If the damage was 'rearward' from the RCC the reentry
would have been successful, so everyone is just pretty damned sure
where the damage was. Read the bloody report.


Also the nature of the damage, was there enough internal structure
to support a patch or was that severely damaged? We don't know
because nobody looked.


And nobody looked because nobody thought the RCC could be damage by a
foam strike and tile damage wouldn't have led to loss of vehicle.


If they did an EVA or had a Canadarm with a remote camera, they
could have made a very accurate assessment of whether it was
repairable, and on day 2.


If they even looked in the right place. Again, nobody believed at the
time that the RCC could be damaged by a foam strike. Kits to repair
damaged tiles didn't exist until years after Columbia, so even finding
tile damage would have made no difference since there was no way to
repair that at the time, either.

snip


That is why I suggested sending an expendable rocket with materials to
for Columbia crew to make an emergency patch. Titanium sheets and
sheets of ablative material and fasteners, for example.


But that quite simply would not work for the RCC wing leading edge. The
best NASA could do was make a repair kit for the tiles.


Again, they didn't know whether it was the leading edge or the exact
nature of the damage. The expendable rocket could send up several tons of various materials, using whatever was deemed necessary.


Again, they were pretty sure it was NOT the leading edge until after
the fact, since no one believed that a foam strike could damage the
RCC. They'd done lots of work on what it took to damage the RCC
because of concerns about on orbit damage (which they'd seen on
various missions), but all that work assumed relatively small
impactors at relatively high velocities. Nobody had looked at impacts
from large chunks of foam at several hundred miles an hour and when
they did look they quickly discovered that such an impact would blow
huge holes in the RCC.

snip


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #68  
Old February 5th 17, 04:24 PM posted to sci.space.history
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default The Space Race was about Power Projection - Miles O'Brien

In article ,
says...
"Scott M. Kozel" wrote:

And again, that would depend on the exact nature of the damage, and that
is unknown due to the fact that they never made any attempt to examine it.
The smaller the hole the higher the chance of a successful emergency
repair. A huge hole might be impossible.


ANY hole in the RCC is impossible.


In the interest of educating other readers, I'll continue to provide
cites. No doubt Fred has read the CAIB Report and understands the
issues involved with using RCC as thermal protection on the wing leading
edges.

True, because without the protection of the silicon carbide (applied to
the outside), the reinforced carbon carbon will erode during reentry due
to oxidation. Because of this, any breach in the RCC will continue to
grow during reentry. This is supported by these paragraphs on page 12
of the CAIB Report:

That conclusion is that Columbia re-entered Earth's atmosphere
with a pre-existing breach in the leading edge of its
left wing in the vicinity of Reinforced Carbon-Carbon (RCC)
panel 8. This breach, caused by the foam strike on ascent,
was of sufficient size to allow superheated air (probably exceeding
5,000 degrees Fahrenheit) to penetrate the cavity behind
the RCC panel. The breach widened, destroying the insulation
protecting the wing's leading edge support structure,
and the superheated air eventually melted the thin aluminum
wing spar. Once in the interior, the superheated air began to
destroy the left wing. This destructive process was carefully
reconstructed from the recordings of hundreds of sensors inside
the wing, and from analyses of the reactions of the flight
control systems to the changes in aerodynamic forces.

By the time Columbia passed over the coast of California
in the pre-dawn hours of February 1, at Entry Interface plus
555 seconds, amateur videos show that pieces of the Orbiter
were shedding...

More details about the RCC and its silicon carbide coating can be found
on page 55 onward. This includes details from previous missions where
RCC started to erode (not good).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #69  
Old February 6th 17, 11:29 PM posted to sci.space.history
Greg \(Strider\) Moore
external usenet poster
 
Posts: 752
Default The Space Race was about Power Projection - Miles O'Brien

"Stuf4" wrote in message
...

JF: Imagine if you had two cars and had to pull the cylinder head from one
and install it on the other when you wanted to use it. Insane, right?"

That is called "cannibalization", and a very common practice in high
performance aerospace vehicles. Hardly ideal, but a cost-effective
approach to maintenance.


It's common, but a bad idea. For many reasons, one, simply being every time
you touch an item, the odds of making a mistake goes up. Not getting a screw
tight enough, forgetting a seal, etc.


JF: "the SRBs ought to have been replaced with reusable liquid boosters"

A fact that so many people are willing to ignore is that the SRBs performed
totally adequately for 24 straight missions. They never failed a single
time. So that's 48 SRB successes in a row. 144 field joints did their
job.


Umm, no, they failed MULTIPLE times. There was hot gasses reaching O-rings
on a number of previous flights. Morton-Thiokol and Marshall were spending a
LOT of time trying to quantify the reasons, the limits and improvements.
Almost every flight had an SRB anomaly .

The only time they failed was when NASA decided to launch with temps WAY
OUT OF LIMITS. Here is an exact quote from Thiokol's Bob Ebeling:

"[W]e're only qualified to 40 degrees ...'what business does anyone even
have thinking about 18 degrees, we're in no man's land.'"
(https://www.nasaspaceflight.com/2007...of-challenger/)


The Ebeling is remembering things wrongly because there was no specific
temperature qualification! There was a range of data they were working
from.


THAT is the one and only proximate cause of the Challenger disaster.


No, it's not.

...and the culpability for this fatal error falls not only on NASA top
management, nor middle management, but the one level of decision-making
that everyone, for whatever reason, chooses to avoid mentioning:

- Operations.

THEY were the ones whose duty was to know these limits better than anyone
else involved in the launch decision. Yet all of them decided to not voice
their objections. That goes for the dozens upon dozens of people in Launch
Control, the many dozens in Mission Control, and also the crew themselves.


Bull****. They had voiced their objections. But they also knew as engineers
that NO system is ever perfectly safe. Hell, if anything most them knew
better than the big-wigs higher up the food-chain that the shuttle was NOT
an operational system and could not be treated as such. At best they could
look at the data they were getting (such as burn-throughs and other issues)
and try to determine why, what the risk was and if they could solve it.


The crew paid for this mistake with their lives.
Other people in operations like Gene Thomas, Bob Sieck, Jay Greene, Fred
Gregory, etc got *promoted*.

That's the most effective way to cover up an egregious error. Everybody
pretend that it never happened. That it wasn't their job to stop the
launch. It's much easier to blame an inanimate object like O-rings even
though they had a track record of a 100% success rate when launched within
temp limits.


Except reality begs to differ from your "alternative facts". There were
issues on almost every single flight. Issues that violated the original
design criteria which specified that NO hot gasses were supposed to ever
reach the O-Rings.

Part of the problem though was that NO one had ever built, let alone FLOWN
SRBs that big. After the first flight, the engineers realized their design
wasn't working as designed. So they were trying to figure out how and why
and what the exact limits of the system were.


SRB field joints had a batting average of 1000. 144 successes with 144 at
bats.

Not a perfect design, to be sure. But it worked when established limits
were respected.

O-rings are *NOT* what killed Scobee and his crew. It was every person
involved in the chain that arrived at the decision that it was a good idea
to launch in spite of the freezing cold temps.


And it likewise needs to be identified that also culpable for these 7
fatalities is everyone from back in the 1970s who was involved in the
decision to not give shuttle crews a viable means of escape. It would have
been very easy to have designed the crew cabin as a breakaway structure.
Being a pressure vessel, it was already robust. Not much more was needed
than a stabilization drogue chute and thermal protection. A set of very
light tiles or blankets would have done the trick. From there, all the
crews would have needed was pressure suits with parachutes.


Sure it would have been simple. And 100% safe because they would have failed
to meet their design criteria of payload.

Such a simple low cost lightweight low-performance-impact solution would
have saved 14 lives. Or if it failed in saving lives, it would have at
least given them a fighting chance. Some glimmer of hope for survival.


Hardly lightweight. And you'd also have needed pyros to make sure you
detached everything (because otherwise one could imagine a situation where
say the crew compartment and part of the payload compartment are stuck
together and too massive for your parachutes. So next thing you're saying
is bigger parachutes. Or other design criteria)

And NASA doesn't like to use any more pyros than necessarily.

In the case of 51-L, something as simple as a sport parachute might have
made the difference between living and dying. This is *half* of what
recreational parachutists use on a daily basis. Just give the astronauts
the "reserve". But no. They were not even given that much.


It would have made zero difference.
For one they would not have made it out of the cabin because of the
tumbling.
For another they would not have made it out of the cabin because they were
unconscious.

And that assumes NO critical injuries due to the break-up itself.


~ CT


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #70  
Old February 6th 17, 11:35 PM posted to sci.space.history
Greg \(Strider\) Moore
external usenet poster
 
Posts: 752
Default The Space Race was about Power Projection - Miles O'Brien

"Jeff Findley" wrote in message
...

In article ,
says...

Jeff Findley wrote:


Agreed that the system was flawed in that it lacked a crew escape
capability on a vehicle that was large, complex, and prone to failure.
As for an escape capsule being a viable add-on to the shuttle, I call
bull****.


And the primary reason that it lacked a crew escape module is because
it was impossible to safely and rapidly terminate thrust to the solids
to allow such a system to work.

Which brings us back to flying human beings on solid boosters is a
special kind of stupid.


Agreed. And the stupidity continues with SLS with some notable
differences. SLS will have a five segment SRB as opposed to the
shuttle's four segment SRB (things that are different just aren't the
same). And the SLS SRBs will not be reused, so there will be no chance
to tear them down and inspect flown SRBs for problems.


And THIS is one of the seemingly unlearned lessons of reusability. Even if
the mony-savings was a breakeven, the information gained was priceless.



Performance uber alles. :-(

Jeff


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

 




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