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CEV combined with upper stage?



 
 
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  #1  
Old September 20th 04, 11:27 PM
Pete Lynn
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Default CEV combined with upper stage?

I have just been wondering if there would be any sense in combining the
CEV, (whatever that may be), with an upper stage propulsion system.

This might give you a flexible and reusable upper stage and perhaps save
some weight over a separate system approach. In addition to negating
the need for a separate upper stage, this might enable a larger
effective CEV on smaller effective launchers. It might also entail a
fluffier effective capsule design, easing reentry requirements.

With refueling this might also directly open up the earth-moon system,
though it is a one size fits all approach.

Would there be any useful advantage to such an approach? Is the added
complexity prohibitive?

Pete.



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  #2  
Old September 21st 04, 10:49 AM
Thomas Lee Elifritz
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September 21, 2004

"Pete Lynn" wrote in message :

I have just been wondering if there would be any sense in combining the
CEV, (whatever that may be), with an upper stage propulsion system.

This might give you a flexible and reusable upper stage and perhaps save
some weight over a separate system approach. In addition to negating
the need for a separate upper stage, this might enable a larger
effective CEV on smaller effective launchers. It might also entail a
fluffier effective capsule design, easing reentry requirements.

With refueling this might also directly open up the earth-moon system,
though it is a one size fits all approach.

Would there be any useful advantage to such an approach? Is the added
complexity prohibitive?


Put a capsule on the Delta IV Medium, and lunar circumnavigation is
possible, using the upper stage as your service module. In LEO, you
could retrofit the upper stage into space station modules. You get
three Delta IV Mediums for the price of a single heavy.

Thomas Lee Elifritz
http://elifritz.members.atlantic.net
  #3  
Old September 21st 04, 02:45 PM
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Thomas Lee Elifritz wrote:
September 21, 2004

Put a capsule on the Delta IV Medium, and lunar circumnavigation is
possible, using the upper stage as your service module. In LEO, you
could retrofit the upper stage into space station modules. You get
three Delta IV Mediums for the price of a single heavy.


Only if your service module, and all of the life support and
guidance propulsion requirements, have a mass that is less
than 4 metric tons for Delta IV-M or no more than about
6 metric tons for Delta IV-M+(5,4).

The Apollo Command Module mass was about 6 metric tons, but
its 24.5 metric ton Service Module carried 1.2 metric tons
of equipment and fuel to produce electricity, water, and
oxygen. It also carried a ton or more of RCS fuel and
hardware needed to keep the vehicle under control. The
latter masses would have to be added to the Delta IV second
stage, which would directly reduce payload capability.

- Ed Kyle

  #4  
Old September 21st 04, 03:11 PM
Thomas Lee Elifritz
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September 21, 2004

wrote:

Put a capsule on the Delta IV Medium, and lunar circumnavigation is
possible, using the upper stage as your service module. In LEO, you
could retrofit the upper stage into space station modules. You get
three Delta IV Mediums for the price of a single heavy.


Only if your service module, and all of the life support and
guidance propulsion requirements, have a mass that is less
than 4 metric tons for Delta IV-M or no more than about
6 metric tons for Delta IV-M+(5,4).


My group is not interested in SRB propulsion, so we are focusing on a 3
ton limit for manned lunar circumnavigation.

The Apollo Command Module mass was about 6 metric tons, but
its 24.5 metric ton Service Module carried 1.2 metric tons
of equipment and fuel to produce electricity, water, and
oxygen. It also carried a ton or more of RCS fuel and
hardware needed to keep the vehicle under control. The
latter masses would have to be added to the Delta IV second
stage, which would directly reduce payload capability.


As I stated, we are focusing on a manned lunar circumnavigation for the
purposes of space advocacy and IMAX and film production, solar power and
hydrogen energy conversion technology promotion, hydrogen propulsion
promotion, and of course, Boeing Delta IV Medium promotion. The mass
fractions are tight for this mission, but should be doable with modern
design criteria, techniques and equipment. To us, it makes very little
sense to actually orbit and land on the moon at this point in the
process.

For LEO it's a bit better, because you get the hydrogen tank for habitat
retrofit, and the oxygen tank for ... oxygen. Here it goal is retrofit
demonstration, and in addition to the above, hydrogen powered SSTO
advocacy and promotion.

CELSS comes later, but we are working with that on the ground.

Thomas Lee Elifritz
http://elifritz.members.atlantic.net

  #5  
Old September 21st 04, 10:54 PM
ed kyle
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Default

Thomas Lee Elifritz wrote in message ...
September 21, 2004
wrote:
Put a capsule on the Delta IV Medium, and lunar circumnavigation is
possible, using the upper stage as your service module.

Only if your (command) module, and all of the life support and
guidance propulsion requirements, have a mass that is less
than 4 metric tons for Delta IV-M or no more than about
6 metric tons for Delta IV-M+(5,4).


My group is not interested in SRB propulsion, so we are focusing on a 3
ton limit for manned lunar circumnavigation.


Sounds like a slimmed-down Lunar Gemini type effort.
Engineering reviews of the time called Lunar Gemini,
possible, but marginal. Earth orbit Geminis weighed
in at more than 3.8 metric tons.

As I stated, we are focusing on a manned lunar circumnavigation for the
purposes of space advocacy and IMAX and film production, solar power and
hydrogen energy conversion technology promotion, hydrogen propulsion
promotion, and of course, Boeing Delta IV Medium promotion. The mass
fractions are tight for this mission, but should be doable with modern
design criteria, techniques and equipment. To us, it makes very little
sense to actually orbit and land on the moon at this point in the
process.


Why not do a privately funded unmanned mission(s) instead?
Wouldn't that accomplish most of these goals? And might
it not be possible to use a cheaper launch vehicle
than Delta IV-M (Delta II, Rokot, Falcon) to actually put
an unmanned spacecraft in lunar orbit?

- Ed Kyle
  #6  
Old September 21st 04, 11:55 PM
Thomas Lee Elifritz
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September 21, 2004

ed kyle wrote:

Why not do a privately funded unmanned mission(s) instead?

Because the world won't be glued to their TV sets and radios for a week
straight, and then go straight to the theatres to see the movie, in
droves. It's all about excitement and drama. Remember what's his name
.... Lindbergh? Imagine if he had a digital video recorder with him, and
made a movie of his flight. We are talking about a week of intense
worldwide space advocacy here.

Wouldn't that accomplish most of these goals? And might
it not be possible to use a cheaper launch vehicle
than Delta IV-M (Delta II, Rokot, Falcon) to actually put
an unmanned spacecraft in lunar orbit?

But then it wouldn't be hydrogen powered, and believe me, that is the point.

Thomas Lee Elifritz
http://elifritz.members.atlantic.net

 




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