Getting large stuff back to earth intact.

"Brian Gaff" wrote in message
. uk...
Without the Shuttle how could any large experiment or item be brought back
to earth?

Why would you want to do that? Yes, I'm being serious. It seems that the
cost of bringing back large items to earth isn't worth the benefit.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

Jeff Findley wrote:
"Brian Gaff" wrote in message
. uk...
Without the Shuttle how could any large experiment or item be brought back
to earth?

Why would you want to do that? Yes, I'm being serious. It seems that the
cost of bringing back large items to earth isn't worth the benefit.


That may be true if you're only interested in reuse, but there is still
a need for post-mortem analysis of some devices to learn how to make a
better one for next time.

And the CMGs may be an example where the (pre-retirement) cost of
bringing one back is less than the cost of fabricating a new one
because of unusual fabication issues.

/dps

robert casey wrote:
[...]
It's probably cheaper to just return the items that need analyzing in a
lab on the ground, or just the data, and toss the rest into a lonely
ocean in a controlled manner. The expense of returning a large item
back for reuse probably costs the same or more than just building a new
replacement.

That may be true if you're only interested in reuse, but there is still
a need for post-mortem analysis of some devices to learn how to make a
better one for next time. Some of those items are large.

And the CMGs may be an example where the (pre-retirement) cost of
bringing one back is less than the cost of fabricating a new one
because of unusual fabication issues. Post-retirement, the costs go up
for a while, but maybe the next try of the inflatable reentry vehicle
(Russian SLBMs willing) will lower the cost again.

/dps

"snidely" wrote in message
ups.com...
And the CMGs may be an example where the (pre-retirement) cost of
bringing one back is less than the cost of fabricating a new one
because of unusual fabication issues.

Only if you ignore shuttle program costs. This makes some sense, but only
if you assume the shuttle program will always be around to service ISS
(which is won't). If you're going to keep the shuttle flying anyway, why
not use it to return payloads like this?

But after the shuttle retires, I seriously doubt NASA will spend the money
to develop a vehicle which could return something the size of a CMG to
earth. It would be possible to do (say an unmanned CEV that opens up like a
Super Guppy), but it won't be worth the cost, so it won't get done.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

Jeff Findley wrote:
"snidely" wrote
And the CMGs may be an example where the (pre-retirement) cost of

Only if you ignore shuttle program costs.

Shuttle program costs are being paid by the up cargo.

But after the shuttle retires,

Note my "pre-retirement" qualification above.

I seriously doubt NASA will spend the money
to develop a vehicle which could return something the size of a CMG to
earth. It would be possible to do (say an unmanned CEV that opens up like a
Super Guppy), but it won't be worth the cost, so it won't get done.

It will get done someday by somebody, but not necessarily in time for
ISS. There *will* be a point where we have vessels coming down (under
control, that is) that have the capability, as economics drive us past
the tiny capability we have now. It may be tourists that are the key
(returning 50 passengers in one flight, for instance), or it may be a
side-effect of lofting large freight in reusable vehicles, but it will
get done ... eventually.

Ask Branson in 10 years, or Bezos, or Spencer, or ....

/dps

"snidely" wrote in message
oups.com...
It will get done someday by somebody, but not necessarily in time for
ISS. There *will* be a point where we have vessels coming down (under
control, that is) that have the capability, as economics drive us past
the tiny capability we have now. It may be tourists that are the key
(returning 50 passengers in one flight, for instance), or it may be a
side-effect of lofting large freight in reusable vehicles, but it will
get done ... eventually.

Ask Branson in 10 years, or Bezos, or Spencer, or ....

I agree. Once you get away from expending *everything* but the crew capsule
and an SRB and start reusing as much as you can, then returning large
payloads as big as what you can launch is almost free. Ares I/Orion is
backing away from more reusability in order to reduce development costs. My
guess is they'll end up spending a lot more development money on Ares V and
the new lunar lander than what will be spent on Ares I/Orion.

A fully reusable TSTO with intact abort throughout the entire flight ought
to let you bring back anything you can launch.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

On Fri, 29 Dec 2006 11:19:39 -0600, Damon Hill
puked:

"Brian Gaff" wrote in
.uk:

Without the Shuttle how could any large experiment or item be brought
back to earth?

Short answer, it can't. If it could be disassembled into
much smaller pieces, the most important parts might be
returnable in Soyuz or Orion--maybe.

Potentially an aeroshell could do the job, but it'd be
expensive and there's not much demand for such a service
at present. The capability wasn't used all that much with
Shuttle, other than SpaceHabs. If a demand develops, I
suppose a capability will be developed, if only as a
cargo-only version of Orion or something similar.

We're going to miss Shuttle's capabilities, on occasion.


Correct me if I'm wrong, but we have landed some relatively large
experiments on Mars...
--
lab~rat :-)
Do you want polite or do you want sincere?

lab~rat :-) wrote:
[...]

Correct me if I'm wrong, but we have landed some relatively large
experiments on Mars...

Yes, the size of large suitcases, but the reduced gravity has bigger
effect on design then does the thinner atmosphere. It may also have
been possible to close on Mars at rate less than orbital speed,
reducing the amount of kinetic energy to be dissapated.

The ammonia device and CMGs are both noticeably larger than the MERs.
ISTR that Sojourner wasn't much larger than truck-size lead-acid cell
batteries.

/dps