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Back to the Future? The Command Module Flies Again?



 
 
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  #1  
Old January 26th 04, 07:26 AM
Rusty B
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Default Back to the Future? The Command Module Flies Again?

Boeing is using Command Module shaped hardware
and an Apollo type escape rocket in some of its recent concept drawings:

According to NASA Watch:

"Boeing has placed a dozen or so graphics online depicting a varety
of spacecraft one would expect to see proposed as part of the
President's new space policy."

http://www.nasawatch.com/

http://boeingmedia.com/images/search...roduct_id=1525

Some earlier Boeing OSP CM capsule shaped concepts.

http://boeingmedia.com/images/search.cfm?product_id=986



- Rusty Barton - Antelope, California


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  #5  
Old January 27th 04, 03:45 AM
William R. Thompson
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John Charles wrote:

I had hoped that, in keeping with the desire for a simpler
entry/descent/landing than the (99% successful) Space Shuttle option,
we might have opted for a self-orienting reentry vehicle for the CEV.
I am thinking of off-nominal cases when even your entry-attitude
rockets might not be working.

Mercury and Gemini were self-orienting (Carpenter mentioned Faget's
confidence of less than a 60-degree oscillation of the nose during
reentry, but I guess it was blunt-end forward, or BEF, on average!),
and Soyuz is, too. But the Apollo command module shape had two stable
entry attitudes, BEF and nose-forward. The launch escape tower
included canards to destablize the nose-forward attitude so the CM
would end up BEF for parachute deployment (IIRC).


Mercury had a small spoiler flap attached to its nose to orient it
blunt-end forward during re-entry. I think it was designed to put
the capsule in that attitude during an abort as well.

--Bill Thompson
  #6  
Old January 27th 04, 05:34 AM
Henry Spencer
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In article ,
John Charles wrote:
...But the Apollo command module shape had two stable
entry attitudes, BEF and nose-forward. The launch escape tower
included canards to destablize the nose-forward attitude so the CM
would end up BEF for parachute deployment (IIRC).


It was a little more complicated than that. The canards were to ensure
base-first orientation during the atmospheric aborts. For an actual
reentry, from a high-altitude abort, even they weren't good enough:
interaction of the tower shock with the CM produced a weak nose-forward
stable position that bigger canards didn't fix.

But since stability there was weak, the CM couldn't settle into that
position if it was rotating at more than about 2deg/s. So high-altitude
abort procedures called for immediately establishing a 5deg/sec pitch
rate, ensuring that it would always stabilize base-first.

While it is nice to have dependable passive stability on reentry, you do
pay a price for it, and the tradeoff needs careful assessment. There is
nothing inherently risky about needing active attitude control early in
reentry; in many cases you need active attitude control to get to that
point anyway. Providing redundant guidance and RCS may be easier,
especially given that you probably want those anyway...

To quote a comment from a 1990 Aerospace Safety Advisory Panel memo:

...for every failure mode someone can envision, someone else must
provide a solution... The proven costs of such solutions are money,
schedule delays, and additional unknowns. I believe that many of
our solutions to problems create more serious problems through added
complication, dilution of effort, and increased time compression on
already over-stressed work loads... Unless management and program
personnel develop a sense of proportion, we will forever be trying
to chase things to the last decimal point, frittering away limited
resources on insignificant issues.

The author of that, by the way, was an astronaut.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |
  #7  
Old January 27th 04, 04:34 PM
Rick DeNatale
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On Tue, 27 Jan 2004 05:34:23 +0000, Henry Spencer wrote:

To quote a comment from a 1990 Aerospace Safety Advisory Panel memo:

...for every failure mode someone can envision, someone else must
provide a solution... The proven costs of such solutions are money,
schedule delays, and additional unknowns. I believe that many of
our solutions to problems create more serious problems through added
complication, dilution of effort, and increased time compression on
already over-stressed work loads... Unless management and program
personnel develop a sense of proportion, we will forever be trying
to chase things to the last decimal point, frittering away limited
resources on insignificant issues.

The author of that, by the way, was an astronaut.


Wow! What a great quote. Of course some of the "experts" who hang out on
usenet would vehemently disagree with this astronaut in the belief that
they could do better and assure safety.

  #9  
Old January 27th 04, 02:15 AM
Rand Simberg
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On Tue, 27 Jan 2004 13:07:31 +1100, in a place far, far away, Stephen
Souter made the phosphor on my monitor
glow in such a way as to indicate that:

In article ,
Brett O'Callaghan wrote:

(Rusty B) wrote:

Boeing is using Command Module shaped hardware
and an Apollo type escape rocket in some of its recent concept drawings:


I guess a good design is a good design, regardless of how old or
recycled it is. ;-)


If Boeing is contemplating recycling the CM, can a recycled Saturn V be
far behind?


Yes. The capsule will be a new design. If a heavy lifter is built,
it will be as well.
  #10  
Old February 1st 04, 06:34 AM
Stephen Souter
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In article ,
h (Rand Simberg) wrote:

On Tue, 27 Jan 2004 13:07:31 +1100, in a place far, far away, Stephen
Souter made the phosphor on my monitor
glow in such a way as to indicate that:

In article ,
Brett O'Callaghan wrote:

(Rusty B) wrote:

Boeing is using Command Module shaped hardware
and an Apollo type escape rocket in some of its recent concept drawings:

I guess a good design is a good design, regardless of how old or
recycled it is. ;-)


If Boeing is contemplating recycling the CM, can a recycled Saturn V be
far behind?


Yes. The capsule will be a new design. If a heavy lifter is built,
it will be as well.


An update...

The 31 January issue of _New Scientist_ magazine has a section with
three articles on the Bush Plan, one of which contains some speculation
about the booster that might be used to send the CEV to the moon.

Three options are mentioned (pp29-30):

1) EOR (off-the-shelf rockets would send components into LEO which would
then be assembled into a craft for a mission to the moon; this would,
however, entail "constructing a space station to work from", which given
the ISS and its history some in NASA, Congress, and this newsgroup may
not be too happy with)

2) Shuttle-C

3) Resurrecting the Saturn V in some form (p29: "NASA is again harking
back to the tried-and-tested Saturn V rocket", the writer notes, adding
that "a modern moon rocket won't be quite the same as the model of 40
years ago". Although "it will be liquid fueled", one of the writer's
informants speculates that it would probably use a new rocket motor,
hybrid fuels, and "myriad technologies undreamed by the Apollo designers
half a century past".)

(Another source pours cold water on the Saturn V idea, claiming "my
guess is that there are no readily accessible plans--and certainly not
in any format that we could make use of".)

--
Stephen Souter

http://www.edfac.usyd.edu.au/staff/souters/
 




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