Columbia - Cooling the Breach

Specific heat of water = 1.0 BTU/lbs/F
Latent heat of fusion of water = 140. BTU/lbs
Latent heat of evaporation of water = 970. BTU/lbs
Initial water temperature = 0 F
Final water temperature = 2000 F
Delta water temperature = 2000 F

Heat absorbtion of water = 1 * 2000 + 140 + 970 = 3110 BTU/lbs

Assumptions:

Asumming the hole in leading edge is 1 ft^2

From page 89 of:
/boss.steamos.com/download/caib/documents/20030711/sts107workingscenario.pdf
Assume the average stagnation heat flux during entry = 40 BTU/ft^2/sec

Assume cooling some of the plasma doubles the heat flux
2 * 40 = 80 BTU/ft^2/sec

Assume the time of entry heating = 2000 sec

Total heating load of the breach = 80 BTU/ft^2/sec * 2000 sec * 1 ft^2
= 160,000 BTU

Water required to cool the breach = 160,000 BTU / (3110 BTU/lbs)
= 51.5 lbs of water
= 6.2 gal of water
= 0.83 ft^2 of water

Gee, only 6 gallons of water required to make it through entry with a one
square foot hole in the leading edge. Maybe, I made a mistake somewhere in
my assumptions or calculations.

Craig Fink

Craig Fink wrote in message arthlink.net...
Specific heat of water = 1.0 BTU/lbs/F
Latent heat of fusion of water = 140. BTU/lbs
Latent heat of evaporation of water = 970. BTU/lbs
Initial water temperature = 0 F
Final water temperature = 2000 F
Delta water temperature = 2000 F

Heat absorbtion of water = 1 * 2000 + 140 + 970 = 3110 BTU/lbs
snip
Water required to cool the breach = 160,000 BTU / (3110 BTU/lbs)
= 51.5 lbs of water
= 6.2 gal of water
= 0.83 ft^2 of water

Gee, only 6 gallons of water required to make it through entry with a one
square foot hole in the leading edge. Maybe, I made a mistake somewhere in
my assumptions or calculations.

Heat is not the only problem with a hole in the wing. At hypersonic
speeds, a crack can set up standing waves that can rip stuff to
shreds. Also, as soon as water gets to 32ºF, it becomes liquid and
blows away.
If you're thinking fill the hole with ice, you'd have to sculpt is
smooth, and cover it with duct tape or something :-)
Harmon

Harmon Everett wrote:

Craig Fink wrote in message
arthlink.net...
Specific heat of water = 1.0 BTU/lbs/F
Latent heat of fusion of water = 140. BTU/lbs
Latent heat of evaporation of water = 970. BTU/lbs
Initial water temperature = 0 F
Final water temperature = 2000 F
Delta water temperature = 2000 F

Heat absorbtion of water = 1 * 2000 + 140 + 970 = 3110 BTU/lbs
snip
Water required to cool the breach = 160,000 BTU / (3110 BTU/lbs)
= 51.5 lbs of water
= 6.2 gal of water
= 0.83 ft^2 of water

Gee, only 6 gallons of water required to make it through entry with a one
square foot hole in the leading edge. Maybe, I made a mistake somewhere
in my assumptions or calculations.

Heat is not the only problem with a hole in the wing. At hypersonic
speeds, a crack can set up standing waves that can rip stuff to
shreds.

Much of entry is at very low dynamic pressure.


Also, as soon as water gets to 32ºF, it becomes liquid and
blows away.

Yeah, water is even worst than aluminum.

If you're thinking fill the hole with ice, you'd have to sculpt is
smooth, and cover it with duct tape or something :-)
Harmon

Of course not. Columbia had plenty of high temperature material onboard.
Stuffing the breach with a bunch of quartz fiberglass cloth, and any other
high temp structural materials that would fit. Add water, and you have a
composite, a huge lump of fiberglass cloth with an ablative resin (water).

Structural fiberglass during the initial high temperature region of entry.

The quartz fiberglass would take the brunt of the heat load, won't conduct
heat to melt the water behind it. As the water melts and trys to escape, it
comes in contact with hot fiberglass turns into gas and flows out the
breach cooling the fiberglass as it goes. The water only has one way out
and that one way keeps the plasma out of the wing.

The fiberglass alone would have probably been enough to get Columbia home,
as long as it kept the plasma off the aluminum. The water just adds some
security.

I can imagine that a quartz fiberglass blanket exposed to the stagnation
heating would melt from the outside in. As it melts, it might form a nice
sheet of molten glass on the exterior and begin to radiate much the same as
the RCC does. Covering the entire leading edge in the area of the breach
with a thin layer quartz fiberglass cloth would end up sealing all the
little crack in the RCC with a noncatalytic layer of molten glass.

I wonder how many gallons of water Columbia dumped overboard to reduce it's
landing weight?

Craig Fink

Craig Fink wrote in message rthlink.net...
snip
Of course not. Columbia had plenty of high temperature material onboard.

Stuffing the breach with a bunch of quartz fiberglass cloth, and any other
high temp structural materials that would fit. Add water, and you have a
composite, a huge lump of fiberglass cloth with an ablative resin (water).

I said: "or something..." I think you're right.

Structural fiberglass during the initial high temperature region of entry.

The quartz fiberglass would take the brunt of the heat load, won't conduct
heat to melt the water behind it. As the water melts and trys to escape, it
comes in contact with hot fiberglass turns into gas and flows out the
breach cooling the fiberglass as it goes. The water only has one way out
and that one way keeps the plasma out of the wing.

The fiberglass alone would have probably been enough to get Columbia home,
as long as it kept the plasma off the aluminum. The water just adds some
security.

I can imagine that a quartz fiberglass blanket exposed to the stagnation
heating would melt from the outside in. As it melts, it might form a nice
sheet of molten glass on the exterior and begin to radiate much the same as
the RCC does. Covering the entire leading edge in the area of the breach
with a thin layer quartz fiberglass cloth would end up sealing all the
little crack in the RCC with a noncatalytic layer of molten glass.

I wonder how many gallons of water Columbia dumped overboard to reduce it's
landing weight?

Ok. you've got a ice/fiberglass composite patch available for the next
time. Its better than the attitude that there is nothing that we can
do, so why try.
Harmon

Harmon Everett wrote:

[snip]

Ok. you've got a ice/fiberglass composite patch available for the next
time. Its better than the attitude that there is nothing that we can
do, so why try.
Harmon

Ever see the scene in the 'Apollo 13' movie where someone dumps on a
table the things known to be available in the spacecraft? *This* is what
you/they have to work with.

Did Columbia have quartz fiberglass blankets handy? Enough water,
*and* the means to get it out to the breach (whose size we'll never
really know)? A means to get it to freeze in place, rather than
immediately vaporize? (In vacuum, it'll be gas or solid. nothing else.)
A means to keep a spacewalker in place while doing this?

Some kind of vacuum-applicable hardening foam for damaged tiles was
considered early in the program. This needs to be revisited, and be
available for 'next time.'

Craig Fink wrote in message k.net...
Joann Evans wrote:

Harmon Everett wrote:

[snip]

Ok. you've got a ice/fiberglass composite patch available for the next
time. Its better than the attitude that there is nothing that we can
do, so why try.
Harmon

Ever see the scene in the 'Apollo 13' movie where someone dumps on a
table the things known to be available in the spacecraft? *This* is what
you/they have to work with.

Did Columbia have quartz fiberglass blankets handy? Enough water,
*and* the means to get it out to the breach (whose size we'll never
really know)? A means to get it to freeze in place, rather than
immediately vaporize? (In vacuum, it'll be gas or solid. nothing else.)
A means to keep a spacewalker in place while doing this?

Some kind of vacuum-applicable hardening foam for damaged tiles was
considered early in the program. This needs to be revisited, and be
available for 'next time.'



The airlock water supply valve and some tubing to deliver it into the wing.
The wing could be precooled so that the water will freeze on contact. Also,
as the water boils it cools and would freeze the water as the gas leaves.
Insert tubing, insert blankets, insert anything else you want, turn on the
water and let it flow. Maybe have several tubes inside the wing to deliver
water to several different spots inside the leading edge.

I believe they also had a lot of mylar bag that their meals are in. They
could have been filled with fiberglass and water then sealed. Take them out
into the payload bay and leave them in a cold spot to freeze. Poke some
holes in the bags and stuff them in the wing too.

There's probably plenty of other ideas out there.

http://www.msnbc.com/news/921637.asp

If you look at the picture in the article. The breach in the leading edge
was in the best possible place in terms of astronauts being able to access
the hole. Any other place would have been a lot harder for the astronauts
to get to and repair.

There are quartz fiberglass blankets all over Columbia, both inside (the
payload bay) and out (top of the Orbiter).

The Orbiter fuel cell generate gallons and gallons of the stuff. It's
usually just dumped overboard to lighten the load on entry and landing.
Just before the deorbit burn, I'll bet they dumped more than enough water
to save their lives. :-(

Craig Fink


I wonder why they did not make the skin under the tiles out of
titanium, at least around the leading edges. Titanium is a poor heat
conductor. I bet the Buran has Ti skin. I wonder if it would be
expensive to reactivate the two Buran orbiters the russians have/or
had.

Zoltan Szakaly wrote:

Craig Fink wrote in message
k.net...
Joann Evans wrote:

Harmon Everett wrote:

[snip]

Ok. you've got a ice/fiberglass composite patch available for the next
time. Its better than the attitude that there is nothing that we can
do, so why try.
Harmon

Ever see the scene in the 'Apollo 13' movie where someone dumps on
a
table the things known to be available in the spacecraft? *This* is
what you/they have to work with.

Did Columbia have quartz fiberglass blankets handy? Enough water,
*and* the means to get it out to the breach (whose size we'll never
really know)? A means to get it to freeze in place, rather than
immediately vaporize? (In vacuum, it'll be gas or solid. nothing else.)
A means to keep a spacewalker in place while doing this?

Some kind of vacuum-applicable hardening foam for damaged tiles was
considered early in the program. This needs to be revisited, and be
available for 'next time.'



The airlock water supply valve and some tubing to deliver it into the
wing. The wing could be precooled so that the water will freeze on
contact. Also, as the water boils it cools and would freeze the water as
the gas leaves. Insert tubing, insert blankets, insert anything else you
want, turn on the water and let it flow. Maybe have several tubes inside
the wing to deliver water to several different spots inside the leading
edge.

I believe they also had a lot of mylar bag that their meals are in. They
could have been filled with fiberglass and water then sealed. Take them
out into the payload bay and leave them in a cold spot to freeze. Poke
some holes in the bags and stuff them in the wing too.

There's probably plenty of other ideas out there.

http://www.msnbc.com/news/921637.asp

If you look at the picture in the article. The breach in the leading edge
was in the best possible place in terms of astronauts being able to
access the hole. Any other place would have been a lot harder for the
astronauts to get to and repair.

There are quartz fiberglass blankets all over Columbia, both inside (the
payload bay) and out (top of the Orbiter).

The Orbiter fuel cell generate gallons and gallons of the stuff. It's
usually just dumped overboard to lighten the load on entry and landing.
Just before the deorbit burn, I'll bet they dumped more than enough water
to save their lives. :-(

Craig Fink


I wonder why they did not make the skin under the tiles out of
titanium, at least around the leading edges. Titanium is a poor heat
conductor. I bet the Buran has Ti skin. I wonder if it would be
expensive to reactivate the two Buran orbiters the russians have/or
had.

I think it's been discussed several times about why they didn't use
titanium. My understanding and opinion is that the Shuttles were built
during the Cold War. While Russia was off building entire submarines out of
titanium, the supply of titanium was very limited in the United States.
Essentially, building the Orbiters out of titanium would have stressed the
available supply of titanium.

Good question about Buran? Don't know the answer, but it would be
interesting. Let's see......

http://www.astronautix.com/craft/buran.htm

http://www.friends-partners.ru/partn...ject/buran.htm

http://pargoo.customer.netspace.net.au/buran.html

Seems that some titanium was used in some of the main structural parts, but
most of buran was aluminum. Interesting article.

Best buran orbital flight test damage pictures I could find.

http://www.columbiassacrifice.com/buran.htm

Interesting pictures. One looks like the bottom of the wing burned through
just aft of the leading edge, out on the left wing tip. Looks like a little
bit of a zipper effect to the damage. Three tiles in a row.

Also, a tile melted near the nose? A few missing tiles.

Craig Fink

Zoltan Szakaly wrote:
snip
I wonder why they did not make the skin under the tiles out of
titanium, at least around the leading edges. Titanium is a poor heat
conductor. I bet the Buran has Ti skin. I wonder if it would be
expensive to reactivate the two Buran orbiters the russians have/or
had.

Ti isn't that great at high temperatures, at 700C, it undergoes a
phase transition, which means you need to keep it under that.
A problem is that you want good heat conduction, in order to carry any
heat loads to the structure, and away.
If you have poor heat conduction, and a constant heat load, then the
skin next to the heat source just melts.


--
http://inquisitor.i.am/ | | Ian Stirling.
---------------------------+-------------------------+--------------------------
"When I use a word," Humpty Dumpty said in a rather scornfull tone, "It means
Just what I choose it to mean - neither more nor less." -- Lewis Carrol

On 7 Aug 2003 07:07:10 -0700, (Zoltan Szakaly) wrote:
I wonder why they did not make the skin under the tiles out of
titanium, at least around the leading edges. Titanium is a poor heat
conductor.

That's why. Aluminum is a very good heat conductor, so it can conduct
the heat that *normally* gets through the TPS away from the leading
edge. That prevents hot spotting which could lead to a point structural
failure. In other words, the whole wing structure acts as an internal
heatsink during re-entry.

Because of the poor heat conductivity of materials like titanium and
stainless steel, hot spots would form right behind the TPS, possibly
compromising the structural integrity provided to the TPS by the
leading edge substructure.

Note that the heat load which *did* get through the breach in the
TPS on Columbia would have melted titanium anyway. Even the
SR71, which does use titanium, has to use the fuel to cool the
skin during high speed flight, and it flies much slower than
re-entry speeds.

Gary

Gordon D. Pusch wrote:

The Russians happen to have a large fraction of the worlds's supply of titanium.
(Most of the rest of it belongs to South Africa.) The Russians have so MUCH
titanium that they can afford to make common implements out of the stuff ---
whereas non-miltary projects in the U.S.A. must make do with lesser materials,
such as Aluminum or steel.

This is just plain wrong. Titanium is actually extremely abundant;
titanium ore is literally dirt cheap, a few pennies per pound.

Titanium *metal* is expensive, but that's because it's been hard to
extract in workable form (the old Kroll process was a batch nightmare),
and because demand has been low so there have been few economies of
scale.

If the Russians have a lot of titanium metal it's because they sunk money
into building titanium production facilities, not because they can save
a few cents per pound on ore costs.

Almost all titanium ore mined goes into the manufacture of titanium
compounds, not metal. The white pigment in paint, for example, is
titanium dioxide.

There's a new solid electrode electrolytic process for converting
titanium dioxide to titanium sponge (the 'FFC Cambridge Process') that
may reduce the cost of the metal.

http://www.msm.cam.ac.uk/djf/FFC_Process.htm

Other new processes are also being investigated

http://www.cartech.doe.gov/research/.../titanium.html

Paul