Thomas Frieling in Spaceflight

[carbon copy of this message being e-mailed to the man himself]

Hi, All..

Saw Thomas Frieling's piece in Spaceflight. Very nice!

No strong feelings either way on whether the shuttle should be ultimately
replaced by either a manned capsule or a small spaceplane, but this brings
up a question I've had in mind for a long time:

Would it be possible to build a reusable CAPSULE? Obviously, it would be
launched on an ELV and still have a disposable SM, but why not build a
series of capsules that can be used repeatedly and save a little money? The
reusability concept must have some validity to it!

Have a good one.

"Michael Gallagher" wrote:
Would it be possible to build a reusable CAPSULE?

Certainly.

Obviously, it would be launched on an ELV and still have a disposable SM,

And why are these obvious?

but why not build a series of capsules that can be used repeatedly and save
a little money?

Much depends on how much refurbishment is required between flights.
The big expense in reflight is all of the integration and testing.


The reusability concept must have some validity to it!

The problem is, the less you re-use, the less you save. Somewhere
along the spectrum between "full re-use" and "zero re-use" is the
balance point, but that point can shift with technology, engineering
tradeoffs, etc... for any given application.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

"Michael Gallagher" wrote in message
...
[carbon copy of this message being e-mailed to the man himself]

Hi, All..

Saw Thomas Frieling's piece in Spaceflight. Very nice!

No strong feelings either way on whether the shuttle should be ultimately
replaced by either a manned capsule or a small spaceplane, but this brings
up a question I've had in mind for a long time:

Would it be possible to build a reusable CAPSULE? Obviously, it would be
launched on an ELV and still have a disposable SM, but why not build a
series of capsules that can be used repeatedly and save a little money?
The
reusability concept must have some validity to it!


It is certainly possible. The bigger question is whether it is cost
effective. According to a number of articles I've seen over the years, NASA
found that returned Apollo capsules were in surprisingly good condition, and
actually did give some thought to reuse. It was not pursued because of the
limited scope of the program and the adequate number of capsules
manufactured and available at the time. I have occasionally wondered if
Russia reuses any Soyuz components. They don't as far as I know, but I
have never seen it discussed one way or the other. One would think that a
certain amount of hardware (e.g. radios and the like) should be readily
reusable, regardless of the bigger issue of the capsule itself.

Would it be possible to build a reusable CAPSULE? Obviously, it would be
launched on an ELV and still have a disposable SM, but why not build a
series of capsules that can be used repeatedly and save a little money?

Yes. During the transition period from shuttle to OSP the capsule and/or
service module can be brought back by a later shuttle flight. This would
require the item to be returned, most probably just the service module, to
be placed in a parking orbit accessible by the shuttle after the shuttle has
completed it primary mission.

Once the shuttle is retired a shuttle free reusable capsule is also
possible. If memory serves the Apollo capsules were intended to be
reusable, they were to "thump" down on land and be refurbished. Again, I
ma working from memory, each Apollo capsule could have bee flown up to five
times. Political posturing about whose congressional district the returning
heroes would thump down in led to NASA to switch to a water landing.
Strongly, being heated to several thousand degrees before taking a sal****er
dunk did nothing for the capsules reusability.

One of the primary arguments against a capsule is the need to mount a full
scale search and rescue effort every time one lands. The Navy billed NASA
through the noose for the use of its vessels and people. But, I have also
seen drawing and notes for a controlled landing by an advance Gemini capsule
using a fabric based, hang glider like Rollo wing. Putting the two together
and a reusable capsule is a very doable and much less expensive than many
make it out to be.

"gmw" wrote:
Once the shuttle is retired a shuttle free reusable capsule is also
possible. If memory serves the Apollo capsules were intended to be
reusable, they were to "thump" down on land and be refurbished.

Your memory fails. Gemini briefly was intended to come down on land
(under a parawing), but Apollo was targeted for a water landing from
the start.

Again, I ma working from memory, each Apollo capsule could have bee
flown up to five times. Political posturing about whose congressional district
the returning heroes would thump down in led to NASA to switch to a water landing.

Your memory fails. There never was any such thing considered.

Strongly, being heated to several thousand degrees before taking a sal****er
dunk did nothing for the capsules reusability.

Your knowledge fails. The interior of the capsule is exposed to
neither great heat, nor sal****er. The heatshield, which is so
exposed, would have to be replaced each time regardless of landing
mode.

One of the primary arguments against a capsule is the need to mount a full
scale search and rescue effort every time one lands.

Your knowledge fails. With few exceptions the capsules came down in
the intended area, and neither search nor rescue was required.

But, I have also seen drawing and notes for a controlled landing by an advance
Gemini capsule using a fabric based, hang glider like Rollo wing.

Your knowledge fails. That's the original intended landing mode for
Gemini, but the parawing was canceled when it had severe developmental
problems.

Putting the two together and a reusable capsule is a very doable
and much less expensive than many make it out to be.

That's an opinion, and a very debatable one at that.

D.
--
The STS-107 Columbia Loss FAQ can be found
at the following URLs:

Text-Only Version:
http://www.io.com/~o_m/columbia_loss_faq.html

Enhanced HTML Version:
http://www.io.com/~o_m/columbia_loss_faq_x.html

Corrections, comments, and additions should be
e-mailed to , as well as posted to
sci.space.history and sci.space.shuttle for
discussion.

On Sat, 09 Aug 2003 13:21:11 -0700, Eddie Valiant
wrote:

I think it would probably make more sense to go the wings or lifting
body route if reusability were your prime concern. Then you'd have the
SM functions in the same airframe and can reuse the whole shebang.

And just to open a line of discussion, what would be the need for a
winged/lifting body concept over a capsule design?

Weight, for one. A crew module descent under parachutes is one thing.
Trying to bring the mass of the entire CM/SM down under chutes,
well... you can volunteer to be the first passenger! Now, a DC-X-like
design with powered vertical landing could work, too, but that also is
fairly far removed from the capsule concept, and we have a lot more
experience with wings and lifting bodies.

What does one do
over the other that would make it preferable? To my way of thinking,
the capsule would be the route to go since there's really no need
[that I can see] to carry large payloads up with a manned crew ala the
space shuttle.

I wasn't talking about the payload, I'm talking about the orbital
maneuvering system, power, long-duration life support, and fuel that
the Service Module carries. They're heavy and expensive, and they're
thrown away with all of the capsule concepts, and even some of the
wing/lifting body concepts.

I'd like to see the SM be reusable, too. Perhaps the design for the
OSP should have a universal cargo arear, where on some missions, the
"cargo" is actually a crew compartment. On other missions, it's an
MPLM or ATV-like cargo module. That way, we get full reusability of
the manned spacecraft, the cargo carrier, and the service module.

Brian

Your memory fails. There never was any such thing considered.


Damm! How did I get so old?

gmw wrote:
Damm! How did I get so old?

Time.

Brian Thorn wrote:
"Michael Gallagher" wrote:
Would it be possible to build a reusable CAPSULE? Obviously, it would be
launched on an ELV and still have a disposable SM, but why not build a
series of capsules that can be used repeatedly and save a little money? The
reusability concept must have some validity to it!

I think it would probably make more sense to go the wings or lifting
body route if reusability were your prime concern. Then you'd have the
SM functions in the same airframe and can reuse the whole shebang.

[This is lousy terminology, by the way, but I will approach that
problem later...]

Why would you not put the 'SM functions' inside the main capsule
if you are designing a capsule for reusability?

The reasons to put them outside are to minimize the re-entry TPS
and recovery systems mass, in a non-reusable system. If you are
going to reuse those systems, the mass multipliers for TPS and
for recovery are the same if you have CM or CM+SM functions in
the one capsule, or if you have CM+SM functions in one winged
or lifting body vehicle.


-george william herbert

Brian Thorn wrote:
But isn't there a point where your spacecraft is just getting too big
to land under parachutes? X-38 already had the largest airfoil ever
flown, and it was still small compared to the conventional wisdom on
OSP designs.

X-38 had the largest parafoil I am aware of being made or tested.
But very large parachute clusters have been used repeatedly and
successfully in the past. The Army has airdropped stuff in that
size range for decades and decades.

And keep in mind... a capsule is going to be lighter for the same
capabilities, as it doesn't have all those dead weight wings etc.


-george william herbert