Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_1/v15no130.txt

Internet Message Format | 1993-07-13 | 10KB

Date: Fri, 21 Aug 92 05:03:51
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #130
To: Space Digest Readers
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Space Digest                Fri, 21 Aug 92       Volume 15 : Issue 130

Today's Topics:
              Energya and Freedom and Soyuz ACRV and...
                   Return of payloads from Freedom
          Saturn class (Was: SPS feasibility and other space
                            space industry
             SPS feasibility / Astrophysical Engineering
superstrings & supralight (was SPS feasibility and other space development)

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Date: 20 Aug 92 11:56:51 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Energya and Freedom and Soyuz ACRV and...
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>Shuttle fixed cost is around $5 billion a year, but support for Fred
>>after PMC will only occupy 1/4th the Shuttle fleet at any given time.
>
>The Shuttle flies eight times a year and four of those are needed for
>Fred resuply. Thus Fred uses 50% of Shuttle at an anual cost of $2.5
>billion (1.5 times the cost of doing the same thing with expendables).

The Shuttle has flown 8 times a year without Endeavor and with Columbia
down for update mods. NASA is taking about 2 months at it's current
leisurely pace, one shift, no overtime, to stack and launch a Shuttle.
There are two pads and room in the VAB for two Shuttle stacks. Thus
with a full fleet of four, NASA should be able to launch once a month
for a total of 12 launches a year if that many missions are available.

That assumes Shuttle lands at the Cape saving two weeks, and that
Shuttle mission time is two weeks in orbit. That leaves two months
prep time before that Shuttle has to fly again.

Shuttle resupply missions should be somewhat simpler to prep than
science missions like Spacelab and Astro where complex payloads need
to be integrated into the payload bay and experiment racks swapped on
the middeck.  So without three shifts and overtime galore, NASA should
be able to do four Fred support missions without seriously impacting
other mission timetables. They *have* flown 8 missions with fewer than
four available Shuttles.

>If we use Shuttle for ACRV then Fred uses 100% of Shuttle flights for
>an anual cost of $5 billion. This is five times the cost of doing the
>same thing with expendables.

This is simply nonsense. The same four launches are required for using
Shuttle as ACRV as for resupply. The resupply Shuttle just stays up
until the next one arrives in three months. Still four launches, and
still four recoveries. The only difference is the duration of the
flight. Thus each of two Shuttles devote a total of half a year in orbit
at Fred. While at the station, the Shuttle provides additional workspace
equivalent to two station modules. The long duration Shuttle is in the
works anyway, and when docked at Fred, it doesn't have to draw as heavily
on it's own expendibles as it would as a free flyer.

Given that Shuttle is used for resupply, it makes sense to just dock the
long duration modified Shuttle at Fred until the next flight. Now if
you do resupply on expendibles, then having the Shuttle at Fred doesn't
make sense simply as an ACRV replacement. Then using Soyuz makes sense.
But the long duration Shuttles *can* do the job for under $2.5 billion
a year while giving additional capacity to Fred. Plus the remainder of
the Shuttle fleet remains alive to do other missions like Astro.

Gary

------------------------------

Date: 20 Aug 92 14:58:25 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Return of payloads from Freedom
Newsgroups: sci.space

[e-mail] writes:

>> Allan you have still not addressed with numbers the propostion that
>the
>> Shuttle will become MORE useful as the return of large payloads
>grows more
>> common in the SSF era.
>>

>WHAT large payloads? There ARE no large payloads until we actually GO
>somewhere. There is nothing in LEO to bring back. And if we do have

    On the contrary, as currently designed, Freedom requires the return
of materials on a regular basis.  The engines are designed in 6 (?) modules
that require refueling on Earth.  Current plans have them being rotated out
on a regular baisis.  Since these are almost certainly too large to return in
a Soyuz, you're going to need to redesign them (previously they would have been
H2-LOX run off waste water but that was expensive), or add a vehicle that
can return moderate size payloads.  Or maybe this was covered and I just missed
it.

>The shuttle has already lived a longer time than most of the really
>early cargo aircraft (ie pre-Ford Trimotor and DC-3). It will have an
>honored place at NASM and will probably be sitting there before 2005.

    Well, just to pick nits, NASM already has a shuttle and DC-3s are still
flying.  One has the equivalent of something like 6 million miles on it.  Pre-
DC-3 craft probably weren't popular for long, but I bet there were some that
flew for 15 years.


--
    Josh Hopkins       [e-mail], or [e-mail]

        "A goal is a dream taken seriously."    -Uncle Walt.

------------------------------

Date: 20 Aug 92 11:24:21 GMT
From: Nick Szabo <[e-mail]>
Subject: Saturn class (Was: SPS feasibility and other space
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:

>It is simple. Look at the growth in size of geosync communications satellites.
>Ariannispace has and that is the basline for the growth into the Arianne 5.

Ariane 5 was sized for Hermes, with the capability of launching multiple
comsats tacked on to the requirments.  With the delays in Hermes that is
now the 5's primary task.  Despite silly Arianespace "studies" trying to
justify a Hermes-sized rocket, the next generation communications
satellites will be the same size (eg Intelsat-K).  They are looking for
standardization, not to force a redesigned launcher for every new generation
of satellite.  Heavy-lift vehicles from Saturn to Energiya to NLS have
not and do not have any sort of commercial market, despite $dozens of
billions spent in them. Even the Titan IV has only a dwindling military market.

If rocket designers want to contribute to expanding space industry, they
need to change the nasty habits they have developed over the last two
decades of slow progress rocketry.  They must stop dictating to
their customers and start giving them the services they need --
standardized, lower cost, more reliable launch.


--
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------------------------------

Date: 20 Aug 92 13:32:54 GMT
From: Gary Coffman <ke4zv!gary>
Subject: space industry
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> Mark Goodman <[e-mail]> writes:
>>There are really no private space launch providers
>>outside the United States -- Arianespace is the closest thing.
>
>So what are Atlas, Delta, and Titan, chopped liver?

Old ICBMs from captive government contractors.

Gary

------------------------------

Date: Thursday, 20 Aug 1992 16:52:44 CET
From: "Hugh D.R. Evans" <[e-mail]>
Subject: SPS feasibility / Astrophysical Engineering
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Dani Eder) says:
>
>I'm working on a book that discusses DISMANTLING planetary bodies
>(and rebuilding them more to our liking, sigh - all that wasted
>mass inside planets doing nothing more useful than holding
>atmospheres down, sheesh what poor design).
>
>
...stuff deleted...
>Methods of disassembly include:
>
>(1) Large body impact
>
>Messy, but quick.  Don't let the pieces re-coalesce into a body
>again.
>
>(2) Big bomb(s)
>
>Again, messy.
>
>(3) Spin up to orbital speed.
>
>You collect stuff off the equator that is now orbital.
>
>(4) Boiloff
>
>Good for removing pesky atmospheres, takes longer to evaporate
>planet.  Use lots of concentrated sunlight
>
>(5) Mining
>
>Mass drivers, tethers, etc.
>
>
>For those who are wondering why I am considering such stuff --
>Understanding how such large scale engineering might be done can
>tell us what to look for around other stars in the search for
>life in the Universe.
>
>Dani
>
>--
>Dani Eder/Boeing/Advanced Civil Space/[phone](w)/232-7467(h)/
>Rt.1, Box 188-2, Athens AL 35611/Member: Space Studies Institute
>Physical Location: 34deg 37' N 86deg 43' W +100m alt.
>***THE ABOVE IS NOT THE OPINION OF THE BOEING COMPANY OR ITS MANAGEMENT.***



Hmmm. I wonder what the environmental impact of redistributing the Earth
would be...:):) :)

Hugh

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------------------------------

Date: 20 Aug 92 14:37:10 GMT
From: Brian Tarbox <[e-mail]>
Subject: superstrings & supralight (was SPS feasibility and other space development)
Newsgroups: sci.space

Can someone explain (simply, please), what superstrings are?

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End of Space Digest Volume 15 : Issue 130
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