Best Tech Heat Shield

The Space Shuttle heat shield has changed over time. Basically they
have replaced tiles with things requiring less maintence on the less
critical (cooler) areas. However, the hottest areas remain tiles.

Suppose someone were to make a shuttle-like craft today. What would
they use for a heat shield on the hottest areas. Would they use more
reinforced carbon-carbon? Are there better things than the current
tile system?

-Curious
-Charles Talleyrand

wrote in
oups.com:

The Space Shuttle heat shield has changed over time. Basically they
have replaced tiles with things requiring less maintence on the less
critical (cooler) areas. However, the hottest areas remain tiles.

Suppose someone were to make a shuttle-like craft today. What would
they use for a heat shield on the hottest areas. Would they use more
reinforced carbon-carbon? Are there better things than the current
tile system?

Reinforced carbon-carbon is probably not a good choice because it is
fragile, as the Columbia accident proved. It is also very expensive and is
overkill for most of the bottom surface, since it is intended only for
protection of the hottest areas of the vehicle.

The best technology depends on the vehicle configuration. A dense vehicle
like the shuttle needs a robust high-temperature TPS while a vehicle with
internal fuel tanks would re-enter mostly empty and, being much less dense,
could get away with less TPS, perhaps even metallic shingles.

There are several alternative TPS schemes that have been suggested, but
none have much experimental data behind them. This is an area that *really*
should be investigated with X-vehicles rather than trying to jump straight
to an operational vehicle.


--
JRF

Reply-to address spam-proofed - to reply by E-mail,
check "Organization" (I am not assimilated) and
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wrote:
Suppose someone were to make a shuttle-like craft today. What would
they use for a heat shield on the hottest areas. Would they use more
reinforced carbon-carbon? Are there better things than the current
tile system?

There are probably superior tile materials, but the shuttle makes its
own life difficult with its re-entry profile.

If you could reduce some of the military requirements on the shuttle,
there are lower temperature metal heat shields that should get the job
done.

Mike Miller, Materials Engineer

wrote in message
oups.com...
The Space Shuttle heat shield has changed over time. Basically they
have replaced tiles with things requiring less maintence on the less
critical (cooler) areas. However, the hottest areas remain tiles.

Suppose someone were to make a shuttle-like craft today. What would
they use for a heat shield on the hottest areas. Would they use more
reinforced carbon-carbon? Are there better things than the current
tile system?

You can start by not having such a dense vehicle like the shuttle. Part of
the reason that the re-entry heating is so bad is because of this issue.
This is directly traceable back to the "orbiter plus drop tank" design. If
you merge these into a single vehicle, then you've got a design that's
mostly empty tankage upon re-entry.

Jeff
--
Remove icky phrase from email address to get a valid address.

wrote:
wrote:
Suppose someone were to make a shuttle-like craft today. What
would
they use for a heat shield on the hottest areas. Would they use
more
reinforced carbon-carbon? Are there better things than the current
tile system?

There are probably superior tile materials, but the shuttle makes its
own life difficult with its re-entry profile.

If you could reduce some of the military requirements on the shuttle,
there are lower temperature metal heat shields that should get the
job
done.

Mike Miller, Materials Engineer

Are you suggesting Columbia could have been brought down with a less
"difficult re-entry profile" if the wing foam damage had been known?
How does "the shuttle make its own life difficult with its re-entry
profile"?

wrote in message
oups.com...

Suppose someone were to make a shuttle-like craft today. What would
they use for a heat shield on the hottest areas. Would they use more
reinforced carbon-carbon? Are there better things than the current
tile system?

Slides on shuttle thermal protection issues and possible future
enhancements:

http://www.futureshuttle.com/confere...stem/Kowal.htm
http://www.futureshuttle.com/confere...ones_73099.htm
http://www.futureshuttle.com/confere...iser_73099.htm
http://www.futureshuttle.com/confere...eves_73099.htm
http://www.futureshuttle.com/confere.../oka_73099.htm
http://www.futureshuttle.com/confere.../Kukucheck.htm

Jeff Findley wrote:
wrote in message
oups.com...
The Space Shuttle heat shield has changed over time. Basically
they
have replaced tiles with things requiring less maintence on the
less
critical (cooler) areas. However, the hottest areas remain tiles.

Suppose someone were to make a shuttle-like craft today. What
would
they use for a heat shield on the hottest areas. Would they use
more
reinforced carbon-carbon? Are there better things than the current
tile system?

You can start by not having such a dense vehicle like the shuttle.
Part of
the reason that the re-entry heating is so bad is because of this
issue.
This is directly traceable back to the "orbiter plus drop tank"
design. If
you merge these into a single vehicle, then you've got a design
that's
mostly empty tankage upon re-entry.

Jeff
--

Amen, Jeff. The best way to cope with high heating is
to avoid it with low planform loading on reentry (one
of the claims in our TPS patent, 4,919,366). Like you,
I have always felt that the ET was a big mistake for
the reason you state--as well as economics.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

Remove icky phrase from email address to get a valid address.

Suppose someone were to make a shuttle-like craft today. What would

they use for a heat shield on the hottest areas. Would they use
more
reinforced carbon-carbon? Are there better things than the current
tile system?

Slides on shuttle thermal protection issues and possible future
enhancements:

http://www.futureshuttle.com/c*onfer...nSys*tem/Kowal...

http://www.futureshuttle.com/c*onfer...nSys*tem/jones...

http://www.futureshuttle.com/c*onfer...nSys*tem/leise...

http://www.futureshuttle.com/c*onfer...nSys*tem/Reeve...

http://www.futureshuttle.com/c*onfer...nSys*tem/oka_7...

http://www.futureshuttle.com/c*onfer...nSys*tem/Kukuc...




Thanks for the slides. The most significant thing I read was ...

"A majority of the TPS design enahncements have been made in the areas
of TPS penetrations rather than the acerage areas."

I also learned there are 318 people working on the TPS system alone.
That amazes me.

The TPS is the second highest cost system on the space shuttle??? How
can that be? I would have thought that the External Tank, the SRBS and
the SSME would all rank higher. Even if they meant that the TPS was
the second highest const item on the orbiter, that still suprises me.
I would have thought the SSME and the avionics and the life support
would all rank higher.

What could they do to improve the acerage areas?

supernova wrote:
Are you suggesting Columbia could have been brought down with a less
"difficult re-entry profile" if the wing foam damage had been known?

No.

How does "the shuttle make its own life difficult with its re-entry
profile"?

There's a saying among aerospace engineers: a plane is a flock of
compromises flying in close formation.

What I was talking about was the design compromises made to give the
shuttle certain attributes desired by its customers, the USAF and NASA.

For various reasons, the USAF wanted the shuttle to be able to steer
quite a distance off its original re-entry path. (It needed a high
"cross-range"). To do this, the shuttle needed to dip deep into the
atmosphere where the heating was more severe. This resulted in the
shuttle using its current heat shield, which gives the required thermal
protection but is fragile.

Other compromises resulted in the shuttle being a fairly dense vessel,
giving it a lot of mass relative to its lifting surfaces. AFAIK, it
doesn't really have an option of staying at higher altitude and
shedding velocity more gently. (Even if it had been able to make a
"more gentle" re-entry, I don't think it would've helped. The hole in
its heat shield would still expose its structure to re-entry plasma.)

So, my point was that if you're redesigning the shuttle then it would
help to eliminate some of those military requirements.

For example, the North American Rockwell shuttle concept...

http://www.astronautix.com/lvs/shuenara.htm

...was able to use a metallic heat shield, had low re-entry G-forces,
and fairly good subsonic performance. But it had minimal ability to
steer during re-entry, which would restrict the times it re-entered.
That's not such a problem for civilian operations. The VentureStar
would also have been able to use a metallic heat shield.

Mike Miller, Materials Engineer

"Len" wrote in message
ups.com...
Amen, Jeff. The best way to cope with high heating is
to avoid it with low planform loading on reentry (one
of the claims in our TPS patent, 4,919,366). Like you,
I have always felt that the ET was a big mistake for
the reason you state--as well as economics.

I Googled for "patent 4919366" which led me to the patent on
http://patft.uspto.gov/, which is pretty cool, considering that they even
have full size TIFF images online. Mmmm, pictures...

Seriously though, the pictures of the vehicle are rather interesting.
They're well worth the time to look at them.

Jeff
--
Remove icky phrase from email address to get a valid address.