Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO599.TXT

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Date: Sat, 26 Dec 92 05:05:08
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #599
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 26 Dec 92       Volume 15 : Issue 599

Today's Topics:
                  asteroids beyond Jupiter (7 msgs)
                  ASTM, Saturn and MOL (Was Re: MOL)
                 Aurora chase planes (was Re: Aurora)
    Breeder reactors (was Re: Justification for the Space Program
                 ISSECCo (Space Colonization Company)
                   Justification for Space Program
             Justification for the Space Program (2 msgs)
                         satellite costs etc.
                       Saturn lift capabilities

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

Date: Sat, 26 Dec 1992 00:32:05 GMT
From: [e-mail]
Subject: asteroids beyond Jupiter
Newsgroups: sci.space

In article <[e-mail]>,
[e-mail] (bill nelson) writes:

> My definition of asteriod is: any body that orginated in the
> "asteriod belt" (between Mars and Jupiter). I have made no claim as to
> where they can orbit. Jupiter is large enough to cause significant
> perturbation to their orbits.

Well, that's nice, but you might want to check the astronomically accepted
definition instead.  And just how do you propose to define origins here?
Do you mean a body that coalesced from the primordial solar nebula at a
mean distance of between 1.4 and 5.2 AU from the center of that nebula?
How would you propose to show where all such bodies were now, or even if
the main belt asteroids all started out there?

> However, it is a long way from Jupiter to Neptune. I am waiting for someone
> to post a reference that states that there are asteriods (by my definition)
> that orbit that far out.

So who the heck are you?  President of the International Astronomical Union?
When Charlie Kowal discovered Chiron it was classed as an asteroid, and it's
orbit takes it well past Saturn.  Yes, Chiron now appears to contain more
volatiles than "typical" asteroids but so what?

-Bill Gawne,  Space Telescope Science Institute

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

Date: 26 Dec 92 01:19:38 GMT
From: William J Jacobs <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: sci.space,alt.folklore.urban

In article <[e-mail]> [e-mail] (bill nelson) writes:
>[e-mail] (J. Furr) writes:
>:
>: I post this whole mess to sci.space and say "help" because it seems that
>: one side in a.f.u. is arguing as follows: _all_ asteroids occur between
>: the orbits of Mars and Jupiter.  Therefore Neptune, Pluto, etc. could not
>: possibly have captured asteroids because asteroids don't go out that far.
>
>Not quite. My definition of asteriod is: any body that orginated in the
>"asteriod belt" (between Mars and Jupiter). I have made no claim as to
>where they can orbit. Jupiter is large enough to cause significant perturbation
>to their orbits.
>
>However, it is a long way from Jupiter to Neptune. I am waiting for someone
>to post a reference that states that there are asteriods (by my definition)
>that orbit that far out.
>
>Bill

O.K., here's a reference for you.  From "A photometric study of (2060) Chiron
and its coma" by R.M. West published in Astronomy and Astrophysics vol. 241
pg. 635.  R. M. West says, "(Chiron) is the most distant minor planet known
at present; the orbital eccentricity is moderately high (e=0.38) and with a
semi-major axis of 13.7 AU, the peri- and aphelia of (2060) Chiron are near
the mean orbital distances of Saturn and Uranus, respectively."

So, as of July 6, 1991, the answer to your question is "no, there aren't
any asteroids that far out".  That really isn't conclusive as we really don't
have the right technology at present to look for them.  We need a larger
Infrared telescope, or maybe a Hubble that isn't all bollixed up.  It seems
to me that there are some asteroids from the belt out there, probably about
the same amount that are found amongst the inner planets (which means not
very many), in a great deal more volume.

Bill Jacobs
Astronomer at large

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

Date: Sat, 26 Dec 1992 01:40:17 GMT
From: William J Jacobs <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: alt.folklore.urban,sci.space

In article <[e-mail]> [e-mail] (bill nelson) writes:
>[e-mail] (Greg F Walz Chojnacki) writes:
>:
>: Although it might seem like I'm paying out rope here, I'm curious about the
>: usage of the terms "asteroid" and "planetoid." Bill, since yours is the first
>: time I saw the distinction made, care to define these? (I hope it's more than
>: asteroids being those things that lie where asteroids were first discovered.)
>
>Nope, that is the distinction I use. Whether it is currently the accepted
>definition is another matter. I define an asteroid to be a body that
>originated in the asteroid belt - others are planetoids or "minor bodies"
>or comets etc.
>
>Flame away, if you wish. My asbestos underwear, while well charred, is still
>functional.
>
>Bill

Just for the record, before we drop this thread entirely, the Illustrated
Encyclopedia of Astronomy and Space defines an asteroid as "A small rocky
body moving in an elliptical orbit around the Sun; asteroids are also called
minor planets"  An asteroid that is currently orbiting within the asteroid
belt is called a "belt asteroid", naturally enough, one that is orbiting in
the orbit of Jupiter is called a "Trojan asteroid", "Apollo" and "Amor"
asteroids are in elliptical orbits that have perihelion within the inner
planets orbits (perihelion = closest aproach to the Sun).  Planetoid is not
an accepted term in Astronomy.

A comet that got perturbed out of the Oort cloud and reperturbed into a near
circular orbit  could be rightfully called a minor planet, but wouldn't be
called an asteroid because it's a chunk of ice not a rock.  A pretty good
example of this is Chiron (not to be confused with Charon).

That clear?  Good.

Bill Jacobs
who really doesn't know much more than you do on the subject, but happens to
be sitting not 10 yards from an Astronomical library

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

Date: Sat, 26 Dec 1992 04:49:26 GMT
From: bill nelson <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: sci.space,alt.folklore.urban

[e-mail] (William J Jacobs) writes:
: In article <[e-mail]> [e-mail] (bill nelson) writes:
: >
: >However, it is a long way from Jupiter to Neptune. I am waiting for someone
: >to post a reference that states that there are asteriods (by my definition)
: >that orbit that far out.
: >
: >Bill
:
: O.K., here's a reference for you.  From "A photometric study of (2060) Chiron
: and its coma" by R.M. West published in Astronomy and Astrophysics vol. 241
: pg. 635.  R. M. West says, "(Chiron) is the most distant minor planet known
: at present; the orbital eccentricity is moderately high (e=0.38) and with a
: semi-major axis of 13.7 AU, the peri- and aphelia of (2060) Chiron are near
: the mean orbital distances of Saturn and Uranus, respectively."
:
: So, as of July 6, 1991, the answer to your question is "no, there aren't
: any asteroids that far out".  That really isn't conclusive as we really don't
: have the right technology at present to look for them.  We need a larger
: Infrared telescope, or maybe a Hubble that isn't all bollixed up.  It seems
: to me that there are some asteroids from the belt out there, probably about
: the same amount that are found amongst the inner planets (which means not
: very many), in a great deal more volume.
:
Thanks, Bill.

Now, could an asteriod which is perturbed out to the orbit of Neptune, be
captured by that planet? If so, what would cause the energy loss that would
be needed to put it into orbit? I doubt if atmospheric braking would do
the trick.

Bill

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

Date: Sat, 26 Dec 1992 04:53:33 GMT
From: bill nelson <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: alt.folklore.urban,sci.space

[e-mail] (William J Jacobs) writes:
: In article <[e-mail]> [e-mail] (bill nelson) writes:
:
: Just for the record, before we drop this thread entirely, the Illustrated
: Encyclopedia of Astronomy and Space defines an asteroid as "A small rocky
: body moving in an elliptical orbit around the Sun; asteroids are also called
: minor planets"  An asteroid that is currently orbiting within the asteroid
: belt is called a "belt asteroid", naturally enough, one that is orbiting in
: the orbit of Jupiter is called a "Trojan asteroid", "Apollo" and "Amor"
: asteroids are in elliptical orbits that have perihelion within the inner
: planets orbits (perihelion = closest aproach to the Sun).  Planetoid is not
: an accepted term in Astronomy.

Thanks again, Bill. Definitions noted - I will use them in the future.
I assume that the asteroids in the orbit of Jupiter are called "Trojan"
because they are all at the two stable Trojan points in Jupiter's orbit.

: A comet that got perturbed out of the Oort cloud and reperturbed into a near
: circular orbit  could be rightfully called a minor planet, but wouldn't be
: called an asteroid because it's a chunk of ice not a rock.  A pretty good
: example of this is Chiron (not to be confused with Charon).
:
: That clear?  Good.

Yep, thanks.

Bill

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

Date: Sat, 26 Dec 1992 06:30:13 GMT
From: Henry Spencer <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: alt.folklore.urban,sci.space

In article <[e-mail]> [e-mail] (bill nelson) writes:
>I assume that the asteroids in the orbit of Jupiter are called "Trojan"
>because they are all at the two stable Trojan points in Jupiter's orbit.

Actually, vice versa.  The Trojan asteroids are called that because they
were named after heroes of the Trojan War.  The Trojan points got *that*
name *from* the Trojan asteroids, which were the first known actual
examples of objects in those positions.

Trivia dept:  the discoverers of the Trojan asteroids originally intended
that those in one Trojan point be named after the Greek heroes and those in
the other after the Trojan heroes.  Alas, one hero got mis-located by
accident fairly early on, and the two groups got mixed up after that.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 26 Dec 92 07:16:59 GMT
From: William J Jacobs <[e-mail]>
Subject: asteroids beyond Jupiter
Newsgroups: sci.space,alt.folklore.urban

>Now, could an asteriod which is perturbed out to the orbit of Neptune, be
>captured by that planet? If so, what would cause the energy loss that would
>be needed to put it into orbit? I doubt if atmospheric braking would do
>the trick.
>
>Bill
>
There aren't many other options.  To lose energy, you need to knock into
something.  You have the choice of lots of little things (the atmosphere) or
one big thing  (Neptune itself).  But I'm really no expert on orbital mechanics,
so I'll some physics jock give more details (should be plenty of folks who
know here in sci.space).

Bill Jacobs
who refuses to pretend he knows what he's talking about one minute longer

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

Date: 25 Dec 92 20:55:08 GMT
From: Henry Spencer <[e-mail]>
Subject: ASTM, Saturn and MOL (Was Re: MOL)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>>...The third stage (S-V) was to have been powered by 2 RL-10
>>engines. The S-V was NOT Centaur...
>
>I can buy the four engines and 6 engine bit, but according to document I
>have found here and the Book "Rocket Scientist" and Medaris's " Cound down
>to Decision" These were desginated the Centaur, although I will go back and
>look and make sure of this just in case.

Stages To Saturn, NASA SP-4206, says specifically that the original S-V
stage was to be a Centaur.  It was slated to be the third stage of the
Saturn C-1 and the fourth stage of Saturn C-2 (which used the S-IV as
its third stage and was to have a new second stage).  (The Saturn C-3
moved things up one more stage, with the S-IV as fourth stage, the
C-2's second stage as third stage, and another new second stage.)

Incidentally, it's important to understand that (a) there were a lot
of Saturn designs proposed -- the same study that nailed down the C-1-2-3
scheme also recomended against proceeding with the Saturn A-1, A-2, and
B-1, and those were only the most promising survivors from a longer list --
and (b) the same name sometimes got re-used (there were at least three
different vehicles named "Saturn C-3" at various times).

>>The 'C' designation was dropped somewhere along the way, with the Saturn C-1
>>becoming simply Saturn 1...
>
>According to Dr. Sthulinger and Konrad Dannenburg the C-1 designation was
>dropped when the CSM was put on the stack...

The C designation was dropped in Feb 1963 when terminology was tidied up.
Before then, it was a C-1 whether or not it had Apollo hardware on top.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 26 Dec 92 06:41:53 GMT
From: Mary Shafer <[e-mail]>
Subject: Aurora chase planes (was Re: Aurora)
Newsgroups: sci.space

On Fri, 25 Dec 1992 20:02:03 GMT, [e-mail] (Henry Spencer) said:

HS> In article <[e-mail]> [e-mail] (Mary Shafer) writes:
>... Remember that flight test, including the chasing, is
>only done by test organizations; operational squadrons (the people who
>routinely fly with weapons) are only rarely involved.  Dryden, for
>example, has absolutely no weapons...

HS> A side issue here is that many people don't understand that weapons are
HS> *dangerous*.  Contrary to what you might think from half-baked war movies,
HS> properly-trained troops treat even hand grenades with great respect and
HS> considerable caution.  Live missiles are dangerous to handle, dangerous
HS> to carry, dangerous to have around.  Even *storing* them safely takes
HS> care and effort.  Aircraft don't fly armed without good reason.

Excellent point, Henry.  You can't even walk in front of an armed
airplane once the streamers have been pulled at the Hot Gun Line.

All the ordnance (missiles and rounds for the cannon) are stored in
bunkers, quite a ways from everything else here at Edwards AFB.  I
understand that there is quite a series of checks before live weapons
ever even get to the aircraft and I know that there are elaborate
precautions taken when they're on the aircraft.  For example, you
don't just pin the missile and taxi the aircraft back to your ramp for
the night--you unload it, store it overnight, and them put it back on
the airplane the next day.  (I should mention that the precautions may
be different at operational bases; AFFTC, being a test organization,
may be more cautious than, say, a TAC base, but I suspect that the
differences are minor.)


--
Mary Shafer  DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
[e-mail]                    Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all."  Unknown US fighter pilot

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

Date: 25 Dec 92 20:19:39 GMT
From: Henry Spencer <[e-mail]>
Subject: Breeder reactors (was Re: Justification for the Space Program
Newsgroups: talk.politics.space,sci.space,alt.rush-limbaugh

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>>Speaking of breeder reactors, why doesn't the U.S. have more of
>>>them?
>>Because they're too damn dangerous.

>
>Hardly. The Candu thermal breeder is about the closest thing we
>have to a passively safe system. Hell they let unsupervised
>college students run them...

I really hate to disagree with a compliment, but alas, this confuses three
different flavors of reactor. :-)

The one they let students run is the Slowpoke, an inherently-safe reactor
(you could wreck the controls with a sledgehammer and nothing would happen)
widely used for research work.  Unfortunately, it doesn't scale up very well
and wouldn't be practical for power production.

The Candu is the heavy-water reactor widely used in Canada, and with a few
overseas sales too, for power production.  They don't let students run one
of those. :-)  It is a very efficient reactor, capable of running on natural
uranium in a pinch, and with a consistently better record of time spent
on-line and operational than most of the US designs.  It's one of the more
prominent examples to point to when arguing that the US should have explored
the reactor design space a bit more thoroughly before picking specific types
for commercial power production.

The Candu is not a breeder, alas.  If you pushed the design hard in that
direction, you could get a small net gain -- fuel out exceeding fuel in --
but it's not the reactor you'd pick for the job.  (If I wanted a thermal
breeder, I'd pick the molten-salt reactor, but I'm not an expert and may
have missed a better alternative.)
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 25 Dec 92 22:08:45 GMT
From: [e-mail]
Subject: ISSECCo (Space Colonization Company)
Newsgroups: sci.space

The following is paraphrased from a message I got, edited heavily..

=======================================================================
ISECCo...the International Space Exploration and Colonization Co.
We are a non-profit organization doing space oriented research and
development.

Our first project is building a biosphere. We want to build a
place that is just large enough to support a person...

There are a few other organizations similar to us, but we are the only
Alaskan group.

Actually ISECCo is more into Doing than Discussing.  One of the reasons
we formed the group is because our members were tired of doing nothing
but Talk about space--we wanted to do Do something Real!!!

We hesitate a little bit to do bliant advertising; we don't want to loose
net access privilages.  Now if someone like you were to talk about us...
that would be a different story.

Send Request for Info to:
[e-mail]

======================================================================
Tell him I discussed it here.. Im doing the advertising and I am not a
member, so if anyone gets in trouble it should be me..


Thank you for your support.. Does anyone have other grassroot or larger space
development companies or groups/clubs/organizations..

Michael Adams
[e-mail]
Alias Ghost Wheel/Morgoth on the Networks..

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

Date: 25 Dec 92 21:54:25 GMT
From: [e-mail]
Subject: Justification for Space Program
Newsgroups: sci.space

Reasons for Space Program: Well maybe with the technology provided by the Space
Rpogram we can better predict the future climatic changes and more and help
Somalia and other places to stop being such a pain on the resources.. Not to
say Somalia deserved what they have, but with out some major changes of their
culture or atleast basic ideas of agriculture and more, they will be back where
they are in a few years. Remember Ethipia next door, it was less than 15 years
since they had the same problems that Somalia has..

Maybe the Space Program is expensive, but is that becuase they are not doing
anything or is that because of poor management? I believe the benefits they
provide are benefitial toa ll, including Somalia.. Maybe the Shuttle is to many
things and can't get any done wuite right, well maybe we need to change our
expectations and build more specific space vehicles..


Michael Adams
Alias: Morgoth/Ghost Wheel
[e-mail]

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

Date: Fri, 25 Dec 1992 20:43:05 GMT
From: Paul Dietz <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Herman Rubin) writes:

 > The US economy might be growing in dollar terms, but not in real terms
 > per capita.  And one does not benefit if others catch up at one's
 > expense.

The US came out of the second world war with the only well-functioning
advanced economy in the world.  Many competitors have now emerged.  Is
it at all surprising that the US is losing or has lost its competitive
edge?  Economic competition causes a strong negative feedback tending
to equalize global wealth.  As technology has become mobile it has
become harder for the US to maintain nearly across-the-board
superiority.

 >>Consider China.  The private sector there will grow more than 20% this
 >>year, and exceed the size of the public sector; aggregate GNP growth
 ...
 >Does the world have enough resources for this?  As I have often said
 >that I consider the US substantially overpopulated for the available
 >resources available to us, what will happen when China attempts to
 >get 4 times as much of them?

I believe so.  I consider the US substantially *under*populated.  This
country will be a bit player in the next century if the population
does not increase sharply.  Fortunately, immigration and higher birth
rates among recent immigrants appear to be making that happening.

 >>Bullshit.  Existing coal plants kill more people than existing
 >>nuclear plants, and we can build nuclear plants that have accident
 >>rates much lower than the current generation, low as they are.
 >
 >There is a misunderstanding here.  We agree on the safety, but the
 >political climate will not let those nuclear plants be built.

My apology; I failed to see the ambiguity.  The answer, I think, is
that if and when nuclear is significantly cheaper than the
alternatives, it will be used; economic self-interest will swamp
ideology.  The world still has copious fossil fuels (and will for some
time).  In any case, nuclear was presented as an existence proof that
effectively unlimited energy is available without going into space; I
was not intending to argue that nuclear will necessarily be the
cheapest source.

 > We had better face the
 >fact that without war we probably would not yet have done much in space,
 >and without the cold war, not much beyond the technology of the early 1950s.

I have to ask: is this a bad thing?

Trillions of (current) dollars were soaked up in the cold war.  It is
likely the world would be significantly wealthier and more advanced
(albeit in different directions) if the cold war had not occured.
Spaceflight Now is not the be-all and end-all of existence.

If spaceflight had developed as a private venture, the first boosters
would likely have been significantly different from the converted
ballastic missiles we got from the cold war.  I suspect they would
have been inherently simpler and cheaper, although with poorer mass
ratios, and would have served as a better foundation for eventual
commercial development in space, even if they arrived later.

    Paul F. Dietz
    [e-mail]

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

Date: 26 Dec 1992 00:56:43 GMT
From: "I am a terminator." <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]>, [e-mail] (Herman Rubin) writes:
> The US economy might be growing in dollar terms, but not in real terms
|> per capita.  And one does not benefit if others catch up at one's
|> expense.

If others catch up, then they can work together with us instead of playing
catch up. If others never made a single step to catch up, I suppose we would
benefit?

|> Academic salaries are lower in real terms now than 20 years ago, and
|> the research which drives the future is being curtailed.  The emphasis
|> on short-term practical results is a vain attempt to keep a reasonable
|> position, and will soon backfire.

I think people should be trained to make research results practical. Also,
research reports should facilitate such efforts. Then those who are inclined
to do research can get a chance to do research without having to worry so
much about making their results practical.

|> The US now has more government jobs than manufacturing.  The universities
|> are catering to the ignoramuses coming out of the high schools, and standards
|> are just about dead.

I reflect on my public school. I think the teachers need to do much better.
They are too afraid students won't work on their own. However, they offered
little motivation to students to work. Students just followed rules to get
marks. They didn't have their hearts in work.

>Consider China.  The private sector there will grow more than 20% this
>year, and exceed the size of the public sector; aggregate GNP growth
>will be in double digits.  At current growth rates, China's GNP could
>exceed the entire OECD's by the year 2010.  The per capita GNP could
>reach current US levels within a generation, at current rates of
>growth.

|> Does the world have enough resources for this?

We must wait and see. Be more efficient. That's an order.

|> As I have often said
|> that I consider the US substantially overpopulated for the available
|> resources available to us, what will happen when China attempts to
|> get 4 times as much of them?

--

Henry Choy
[e-mail]

"The Log Song", from Ren & Stimpy

   "What rolls down stairs alone or in pairs
    Rolls over your neighbor's dog?
    What's great for a snack and fits on your back?
    It's Log, Log, Log!

    It's Log, Log, it's big, it's heavy, it's wood.
    It's Log, Log, it's better than bad, it's good!
    Everyone wants a log! You're gonna love it, Log!
    Come on and get your log! Everyone needs a Log!"

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

Date: 25 Dec 92 20:43:02 GMT
From: Pat <[e-mail]>
Subject: satellite costs etc.
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>... A ten year life zero defects
>>GEO comsat like K2 is much cheaper than a 1 year life package
>>that costs 20 times less. That's because most of the investment is
>>not in the satellite, it's in the Earth based terminals that use it.
>
>I don't grasp this argument.  It's the same Earth-based terminals either way.
>If you're providing a service, you plan to do so over more than one satellite
>lifetime, either way.  Twenty years of service is cheaper with mass-produced
>short-life satellites, even with your (fairly unfavorable) assumptions.
>

Actually, henry.  both of you are sticking to the clarke orbit model.

Most of the effort in the Telecom industry is oriented towards
LEO comm sats.  store and forward or multiple fast relay satellittes.

in this case,  the degree of investment in the ground terminals  becomes
very small,  terminals costing under $1,000.00  and satellittes being
cheaper,  because they are smaller, lighter and need less powerful elements.
Obviously,  for a 72 sat constellation, like motorolas  or Inmarsats 21
sat config,  you want to try and keep the lifetimes up,  but if launch
costs drop significantly,  then you can deal with replacing birds
on a regular basis.


>>... Since the satellite represents a single point failure node...
>
>This is your assumption, not a self-evident fact.  Communications networks
>normally have redundancy to cover predictable single-point failures.
>Even today's gold-plated satellite networks do, despite the expense.
>

Actually,  most comm sats,  have lots of extra solar cells,  spare
gyros and thrusters  and spare transponders to handle loss of units.

now if there were some cheap way to go up and refurb these birds,  then
you would be talking some real savings.
>>... and since for most orbits
>>the satellites aren't retrievable or repairable, and DC won't change
>>that...
>
>Again, your assumption, not a self-evident fact.  Cheap launches change
>almost everything, including the feasibility of retrieval and repair.


Oncve again,  for LEO  commsats,  rendevous is quite feasible.

you could even use the shuttle to  grab them up.



pat

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

Date: 26 Dec 92 07:35:48 GMT
From: Henry Spencer <[e-mail]>
Subject: Saturn lift capabilities
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>>... The Saturn 1B could lift the CSM or the LM, but not both (i.e. it
>>could not carry the full Saturn V payload to LEO).
>
>From my information this was always the program intent of the Saturn 1B. This
>helped to lower the costs for the test program of the full Saturn V by flying
>most of the Saturn V hardware before the big bird was ready. According to
>folks here at MSFC the 1B could lift that weight...

Dennis, please back this up with numbers.  The references say that the
1B's orbital payload was circa 18 (metric) tons, which compares rather
unfavorably with the total Apollo orbital weight of 45 tons.  (It was
closer to 50 tons at launch, with the escape tower and protective cover,
but those were shed on the way up.)  This is *not* a small discrepancy.

Could it be that someone got confused because the 1B's available payload
to orbit was circa 45000 *pounds* and the Apollo mass was circa 45000
*kilograms*?

>Remember that the ASTP payload was the full up CSM as well as the docking
>adaptor and the launch was to a 51 degree inclination orbit. This easily
>equals the weight of the Lunar Module in a 28.5 degree orbit.

Uh, Dennis, the ASTP payload was *not* a "full up" CSM; indeed, it was
the lightest CSM ever flown manned, because it needed almost no main-engine
fuel for its mission.  (In fact, it carried more RCS fuel than main-engine
fuel.)  It weighed 12.7 tons.

Furthermore, the docking adapter was tiny, weighing only 2 tons.  The
combination weighed about as much as Apollo 7's CSM, and only about 800kg
less than the Skylab CSMs (which were also launched into high-inclination
orbits, and at higher altitudes to boot).

With tanks *empty*, a CSM-LM combination might just have been able to go
up on a 1B.  But that configuration couldn't have flown a useful mission.
The Apollo 9 Earth-orbit-test CSM-LM stack weighed 36 tons, far beyond
the 1B's lift capability.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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End of Space Digest Volume 15 : Issue 599
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