LSAM

Don't know if this has been discussed before, but I noticed some time ago
that the LSAM will be discarded after it performs its duties. What are some
thoughts on a less wasteful approach:

1) An LSAM that travels between lunar orbit and lunar surface in one piece
(reusable),
2) A CEV that goes from ground-to-earth-orbit-and-back ONLY (crew taxi),
3) An Earth/Moon transfer vehicle that ONLY goes between earth orbit and
lunar orbit (reusable; stationed at ISS),
4) A fuel/cargo/resupply transfer vehicle that takes stuff anywhere.

Maybe this is too complicated, but it seems wasteful to me to throw away one
LSAM for each access to the lunar surface.

Jon

*From:* "Jon S. Berndt"
*Date:* Thu, 06 Apr 2006 06:25:46 -0400

Don't know if this has been discussed before, but I noticed some time
ago that the LSAM will be discarded after it performs its duties.
What are some thoughts on a less wasteful approach:

1) An LSAM that travels between lunar orbit and lunar surface in one
piece (reusable),
2) A CEV that goes from ground-to-earth-orbit-and-back ONLY (crew
taxi),
3) An Earth/Moon transfer vehicle that ONLY goes between earth orbit
and lunar orbit (reusable; stationed at ISS),
4) A fuel/cargo/resupply transfer vehicle that takes stuff anywhere.

Maybe this is too complicated, but it seems wasteful to me to throw
away one LSAM for each access to the lunar surface.

Jon

I think an expendable LSAM saves cash!

A reusable one would need a complicated restartable rethrottleable
descent / ascent stage engine, whereas the ones planned for the separate
ascent and descent stages are very simple and robust, hence cheap.

That's why I was a bit surprised that the cargo booster will use SSMEs -
that too is a very complicated and expensive design for an expendable
booster.

(Derek Clarke) wrote:

:I think an expendable LSAM saves cash!
:
:A reusable one would need a complicated restartable rethrottleable
:descent / ascent stage engine, whereas the ones planned for the separate
:ascent and descent stages are very simple and robust, hence cheap.

Then why don't we use disposable cars and aircraft?

Expendables are only 'cheaper' because nobody has expended the capital
investment to design a 'reusable' set up for minimum operating costs.
Even the phrase 'reusable' implies there's a high turn-around cost. We
don't need 'reusable' vehicles; we need vehicles that operate like
planes, trains, and automobiles, with minimal maintenance other than
refueling between trips.

--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney

*From:* "Fred J. McCall"
*Date:* Sun, 09 Apr 2006 08:05:19 -0400

(Derek Clarke) wrote:

:I think an expendable LSAM saves cash!
:
:A reusable one would need a complicated restartable rethrottleable
:descent / ascent stage engine, whereas the ones planned for the
separate :ascent and descent stages are very simple and robust, hence
cheap.

Then why don't we use disposable cars and aircraft?

Expendables are only 'cheaper' because nobody has expended the capital
investment to design a 'reusable' set up for minimum operating costs.
Even the phrase 'reusable' implies there's a high turn-around cost. We
don't need 'reusable' vehicles; we need vehicles that operate like
planes, trains, and automobiles, with minimal maintenance other than
refueling between trips.

Planes have quite a high percentage of maintenance hours compared to
flight hours actually, and of course space vehicles are more demanding
yet.

While I agree in theory with the ideal of having completely reusable
vehicles, sometimes you just have to accept that throwing bits away is
the most economical course in practice.

"Derek Clarke" wrote in message

While I agree in theory with the ideal of having completely reusable
vehicles, sometimes you just have to accept that throwing bits away is
the most economical course in practice.

Maybe "reusable" is a word that leaves a bad aftertaste. I didn't mean
"reusable" so much as I meant "a vehicle with a purpose to act as a lunar
orbit/surface/orbit taxi continuously". "Operational". This thread was
continued at sci.space.policy. John Schilling posted there on this topic and
I think he makes some good arguments for a single CEV/LSAM vehicle.

Jon

On Thu, 13 Apr 2006 09:00:45 -0400, in a place far, far away, "Jon S.
Berndt" made the phosphor on my monitor glow in such
a way as to indicate that:

"Derek Clarke" wrote in message

While I agree in theory with the ideal of having completely reusable
vehicles, sometimes you just have to accept that throwing bits away is
the most economical course in practice.

Maybe "reusable" is a word that leaves a bad aftertaste. I didn't mean
"reusable" so much as I meant "a vehicle with a purpose to act as a lunar
orbit/surface/orbit taxi continuously". "Operational". This thread was
continued at sci.space.policy. John Schilling posted there on this topic and
I think he makes some good arguments for a single CEV/LSAM vehicle.

I think that "in-space refuelable" is a better descriptor of what is
needed. Of course, that also implies an infrastructure of propellant
depots and the means of keeping them topped off, at various locations
throughout cis-lunar space.

"Jon S. Berndt" wrote in message
...
Don't know if this has been discussed before, but I noticed some time ago
that the LSAM will be discarded after it performs its duties. What are
some thoughts on a less wasteful approach:

1) An LSAM that travels between lunar orbit and lunar surface in one piece
(reusable),
2) A CEV that goes from ground-to-earth-orbit-and-back ONLY (crew taxi),
3) An Earth/Moon transfer vehicle that ONLY goes between earth orbit and
lunar orbit (reusable; stationed at ISS),
4) A fuel/cargo/resupply transfer vehicle that takes stuff anywhere.

Maybe this is too complicated, but it seems wasteful to me to throw away
one LSAM for each access to the lunar surface.

Jon


This is a valid comment. I to have looked at this layout and wondered the
same thing.
Specifically, several approaches should be used - BUT the economics (and
complexity) will determine the viability.

1.) What is eventually left on the lunar surface (descent stage, tanks,
etc.) - become the 21st material scrap yard for future human activities
(e.g. moon bases, raw metals)

2.) Under the current LSAM design that I have looked at
http://forum.nasaspaceflight.com/pho...23&photoid=151

Looks like a cross between an ISS Alpha habitat module and

a Space:1999 "Eagle Transporter" forward section.
http://www.starshipmodeler.com/tech/eagle39.jpg

After docking in lunar orbit - you have (already in space - that does not
need to be launched from Earth's gravity well) -
a human "crew compartment" with flight controls, basic computer; navigation
and environmental system.

3.) For re-use - you just need the expendables (e.g. Oxygen,
Hydrogen/Methane) - and handful of repair parts.

+ Add a truss system - like on ISS Alpha - and make it look like an Eagle
http://www.starshipmodeler.com/tech/epass6.jpg
http://www.starshipmodeler.com/tech/eagle41.jpg

+ Add a smaller maneuvering system (e.g. Russian Parom space tug, or ESA
ATV) -
and it becomes a space taxi (e.g. Star Trek space dock versions) for use in
Earth, Lunar or Mars orbit or LaGrange Points for scientific studies or
"new" experimental manned space craft (ion, nuclear, etc.)

The idea dates back to Korolev's early circumlunar plans, but at that point
he thought Vostok could be developed
into a tug. The Parom is just a mature version of this concept.

Current Parom design specs:
Parom will be built around a pressurized transfer passage with docking ports
at each end: one to dock to the cargo module, the other to dock to the space
station.
It will have its own engines, along with propellant transfer lines to feed
from the cargo canister into its own tanks or into the space station's
tanks.
It will also have engines scaled to handle cargo modules weighing up to
60,000 pounds, twice the mass of the largest station sections carried into
orbit aboard space shuttles.

+ Add a new "fresh" descent stage for another lunar landing

g. beat