Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V15_6/V15NO628.ZIP/V15NO628

Internet Message Format | 1993-07-13 | 32KB

Date: Mon,  4 Jan 93 05:00:04
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #628
To: Space Digest Readers
Precedence: bulk


Space Digest                Mon,  4 Jan 93       Volume 15 : Issue 628

Today's Topics:
                       Aluminum as Rocket Fuel?
                       Biosphere 2 Agriculture
           Galileo's high-gain antenna still stuck (3 msgs)
                       GOVERNMENT-RUN PROGRAMS
             Justification for the Space Program (3 msgs)
       Let's be more specific (was: Stupid Shut Cost arguement
                       lunar military position
                           Media and space
                              Poker Flat
                    russian solar sail?+ (2 msgs)
                       SSTO vs 2 stage (2 msgs)

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: Sun, 3 Jan 93 20:20 GMT
From: Karl Dishaw <[e-mail]>
Subject: Aluminum as Rocket Fuel?

>george william herbert writes:
>aluminum is the wrong fuel to use if it's an earth based application.

Most discussion has centered on an Al rocket being used for exporting
Lunar material, probably as a second stage to a mass driver or laser
launcher.  A mass driver would need a rocket on its payload anyway for
orbit circularization and course corrections.  Aluminum is the most
energetic of the common lunar materials (runner-ups Si, Ti, Fe, Mg, Ca).

>Bruce Dunn writes:
>When the
>aluminum is melted in the tank, the fuel line, valve, and injector will all
>be heated to above the melting point of aluminum.

I'd hate to see the performance hit from carrying a heater that
powerful.  Wouldn't it make more sense to pump the aluminum onto the
rocket as a liquid and only have a heater powerful enough to offset
cooling?


Karl
sold my soul to Uncle Sam . . . now marked down for resale.

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

Date: Sun, 03 Jan 93 15:24:00 PST
From: [e-mail]
Subject: Biosphere 2 Agriculture





My name is Jane Poynter, the Biospherian in charge
of the Field Agricutlure Systems inside Biosphere
2.  Taber MacCallum has given progress reports on
Biosphere 2 and given general outlines.  I thought
I would give a brief outline of the Agriculture
Biome of Biosphere 2.  What I write here are my
own opinions and not to be taken as opinions held
by Space Biospheres Ventures.

The Biosphere 2 Agriculture covers an area of
approximately 0.5 acres, which includes the field
agriculture, orchard and domestic animal barns.
It was designed to produce enough food for the 8
biospherians and domestic animals (goats and
chickens), to be non polluting and totally
recycling.

Our main staples are beans (mostly a tropical
variety called hyacinth bean, or lab lab), rice,
wheat, sorghum, sweet potatoes, taro, bananas
(green as a starch and ripe as a fruit), papayas
(also green as a vegetable and ripe as a fruit),
peanuts (which give us a large percentage of our
daily fat intake), and of course all sorts of
vegetables such as carrots, squash, eggplant,
tomatoes, chilis, bell peppers, beets and lots of
greens.

>From the animals we get mainly milk and eggs.
Meat is quite a luxury, eaten once a week and for
feasts.  We currently have 4 African Pigmy does,
one buck and 2 kids, 10 hens, 2 cocks and 3
pullets.  There are also tilapia fish in the rice
paddies which live off the azolla (a small water
fern which grows on the surface of the water) and
the small crustacea and insect larvae in the water
and mud.  At the outset of the experiment we had
included a breeding pair of Ossabaw Ferrel Swine,
which are a medium sized pig, somewhat larger than
the Vietnamese Potbellied Pig, but much smaller
than a farm pig.  The boar weighed 110 lbs.
However, it became increasingly clear that this
pig, and probably any pig, is not suitable for
this agriculture system at its current level of
production.  There was no starch available for the
pigs, as had been thought there would be when the
decision was made to include the pigs.  I am sure
that this agriculture system will go through many
phases of evolution as we discover what works and
what does not, and how to improve on existing
systems.

We use no polluting pesticides to control pest
outbreaks.  We use soap and other such sprays
where necessary, and use many of the commonly used
methods of integrated pest programmes.  We also do
not use chemical fertilisers, but recycle waste
products.  Animal wastes and crop residues not fed
to the domestic animals are composted, human
waste, the wash down from animal barns and the
waste water from the human habitat is cycled
through a marsh waste recycling system.  Our
nutrient recycling in the agriculture is therefore
essentially a closed loop.  There are some
nutrients that may be tied up in forms
unretrievable by plants in the long run, and this
is a possible problem that we may have to face in
the future.

As in all new ventures there have been problems
which we are currently attempting to solve, and
doubtless there will be many more challenges along
the way to reaching the afore mentioned goals.
Some of our main problems have been in pest
management which has led to problems with crop
diversity.  Light levels are also of concern as
the plants receive approximately 45% ambient
light. This is because of the shading of the
structure and glass.  The pest problems have
arisen because, despite efforts to introduce a
wide variety of predators and parasites on several
occasions, before closure and once during closure,
the food web is by no means complex enough to
handle the fluxes in pest populations.  We have
also seen the development of damaging population
levels of broad mites which we did not see before
closure at all. This tiny mite has devastated
white potatoes, and is now attacking our sweet
potatoes, despite efforts to control it by
spraying vegetable oil (which we have found to be
the most effective non-toxic spray to date) and to
lower levels of relative humidity as far as
possible as this seems to be the most effective
method of population control.

Because of this and other pest and disease
problems our species diversity has been diminished
in the agriculture which of course does not help
in itself.  We begin to rely on fewer and fewer
crops for our main staples, which is not a healthy
situation to be in, especially when one's lively
hood relies upon the crops' success.  Species
diversity is an important factor to consider in
any agriculure system as it is necessary to have
several crops that perform the same funtion in the
diet (such as white potato and sweet potato).
Unpredictable growing conditions may arise and one
crop may do well where the other may fail.
Diversity is also important to maintain an
interesting diet, one aspect of keeping high
morale among the crew of any long expedition.
Both the pest problems and the species diversity
are problems that we are currently trying to
solve, but will also be a large part of the work
being done during the transition phase betwen this
2 year experiment and the next one year
experiment.

Then there is the problem of light: the plants
will indeed grow and produce under the existing
light levels, but it makes the plants somewhat
etiolated and much more susceptible to disease and
prone to pest infestations.

People have often asked what the Biosphere 2
Agriculture system has to do with space
exploration, habitation.  There are several
answers to that question, but the general answer
is in long term colinization of planets, and
eventually even the totally man made space
colonies as in Gerard O'Neill's vision of the High
Frontier.  There are indeed many methods of
growing plants.  NASA is doing great work in the
realms of hydroponics for maximum efficiency and
reliability in the production of food and have
succeeded in obtaining extraordinary yields,
making the production of food a viable option
during spaceflight.  However, this kind of system
is as yet non-recylable.  The nutrient solution
itself can be recycled, but no way has been found
to date to recycle the nutrients that have been
taken up by the plants themselves.   Hydroponics
will most probably be the way to go for space
flights needing to get materials up out of a deep
gravity well, like that of Planet Earth's, but in
situations where there are materials at hand with
which to make the main bulk of the growing medium,
like on Mars, or possibly larger asteroids, then
the soil based totally recycling, non-toxic, intensive
agriculture approach may well be more viable in
the long run. I will say, however, that I think
domestic animals will be a long time in arriving
in space and are not an essential part of our
system, either for nutrient recycling, or for food
production.  They are currently essential for a
good portion of the fat in our diet, but this can
be remedied by the inclusion of other oil crops.

Another aspect of the food production systems
used in space, is the diversity that can
be produced for the human diet.
Living inside Biosphere 2 for 15 months has
shown that food, and the cuisine aspects of the
daily meals, is an extremely important aspect of
group morale.  If someone cooks a poor meal, or if
there is a period of time when the number of
species which end up on our plates is low, or very
monotonous for a period of time, people become
grumpy and somewhat dispondent.  However, feasts
have become very important, where we all make
great efforts to produce favorite dishes like
cheesecake and sweet potato pies, stuffed
chickens, ice creams, rice and peanuts, chutneys
and crepes.  Whilst humans can, for the most part,
tolerate poor living conditions for periods of
time, they do nothing to contribute to group
morale, and high morale on any long space
expedition will be extremely important to ensure
success.

In any food production system in space there must
be room for unpredictablility and failure.  Plants
will be plants.  They will grow very differently
with only very small changes in evironmental
parameters, and problems will arise that were not
seen before, or planned for, as we have seen with
the Bisophere 2 agriculture system.  Although many
crop and variety production trials were run under
conditions as close to those in Biosphere 2 as
possible many plants have acted quite differently
under actual Biopshere 2 conditions.  Bananas have
become an extremely high producer for us in here,
which we did not experience in our test beds.

Pests are of great importance to consider.  Even
in NASA's environmentally controlled chambers
where they take great precautions against the
inclusion of pests they have seen problems with
pests.  Learning how to exclude pests completely
from a system is very important but there needs to
be a back up system of pest management if
unexpected pest populations do arise.  This
non-toxic integrated pest management approach,
with complex food webs, is an important aspect of
the resarch being done in Biosphere 2.

Energy is a big concern in space, both the
acquisition of the energy for artifial lighting
etc. but also the dealing with the heat load
created by electric motors, lights etc.  Using the
sun's photons as far as possible seems the obvious
way to go, but some artificial lighting may be
needed for periods of time or for general
supplementation.  Finding the optimum light levels
for food production, which may not necessarily be
the ideal levels for maximum production/unit area,
is another important area of research which needs
to be carried out.

There are many questions to be answered about food
production systems and many yet to be asked that
have not been thought of, but you might say that
the Biosphere 2 Agriculture system is a
step towards the total system's approach to space
agriculture.  This approach and the as yet
non-recyclable systems of hydro and airoponics
have very different applications, just as the
different rocket propulsion systems have their
pros, cons and very different applications.

I would welcome food production as a new
thread on the net.

Jane Poynter
Biospherian in charge of
Field Agriculture Systems in Biosphere 2







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

Date: 3 Jan 93 16:19:18 GMT
From: Peter Monta <[e-mail]>
Subject: Galileo's high-gain antenna still stuck
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

> The on-board computers don't have the horsepower to do serious compression
> at 100-odd kbps.

Perhaps the DSN improvements currently in the pipeline would increase
the HGA raw data rate, so that the processors would just have to send
the data faster.

Speaking of which, as I understand it, the claim is that the link
capacity can be increased 10-fold.  For HGA, that would give some
1+ Mb/s (assuming the better code could be run at that rate).  That is
remarkable.  Where does it come from?  The Gaspra briefing notes say
that the system noise temperature will drop to 12K, 4K better than
current; that's a couple dB.  This means that maybe 8 dB has to come
from more aperture, better coding, or out of the link margin: is there
that much reserve in the DSN?  Such a state-of-the-art system would be
hard to improve more than incrementally, I would have thought.

How will the arraying be done?  Is it real-time or recorded,
combined offline?  What coding is used?  Leech's notes mention
a "50% higher data rate", plus "several magnitudes better" error
rate; this might be another 2 dB.  That's a large jump, and the
natural question is why the new code wasn't used in the first
place.

A previous poster suggested chirping the motor:  does the spare
HGA on the ground show any such useful mechanical resonances?

I think many of us here in non-JPL-land are watching all of this
with intense interest and excitement.  Best of luck.

Peter Monta   [e-mail]
MIT Advanced Television Research Program

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

Date: 3 Jan 93 18:28:12 GMT
From: "Peter J. Scott" <[e-mail]>
Subject: Galileo's high-gain antenna still stuck
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Dave Michelson) writes:
> In article <[e-mail]> [e-mail] (Ron Baalke) writes:
> >The hammering sessions will continue all the way through the entire month
> >of January, if necessary.  Even though the first hammering attempt didn't
> >open up the antenna all the way, it did have a postive effect.
>
> !!  It did?  I sure don't remember seeing reference to that in the last
> report but I'm glad to hear it.
>
> What was the "positive effect"?  How was it determined or measured?

The GLL nav team chief told me the other day that although nothing
had unfurled, the degree of bowing had increased.  This was determined
from sun sensor data.  On the premise that any movement is better than
none, this is a positive effect.  They're quite prepared to break the
HGA if necessary, assuming they can.

--
This is news.  This is your       |    Peter Scott, NASA/JPL/Caltech
brain on news.  Any questions?    |    ([e-mail])

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

Date: 3 Jan 93 19:13:00 GMT
From: Ron Baalke <[e-mail]>
Subject: Galileo's high-gain antenna still stuck
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] writes...
>In article <[e-mail]>, [e-mail] (Dave Michelson) writes:
>> In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>> >The hammering sessions will continue all the way through the entire month
>> >of January, if necessary.  Even though the first hammering attempt didn't
>> >open up the antenna all the way, it did have a postive effect.
>>
>> !!  It did?  I sure don't remember seeing reference to that in the last
>> report but I'm glad to hear it.
>>
>> What was the "positive effect"?  How was it determined or measured?
>
>The GLL nav team chief told me the other day that although nothing
>had unfurled, the degree of bowing had increased.  This was determined
>from sun sensor data.  On the premise that any movement is better than
>none, this is a positive effect.  They're quite prepared to break the
>HGA if necessary, assuming they can.

The sun sensor data has indicated that the hammering has affected the
antenna in some way.  Either the tension on the antenna has been increased
or a rib has sprung loose, it cannot be determined which way at this point.
Some clarification on "breaking the HGA".  The two motors may apply enough
force to be able to break the stuck ribs, but having an open High Gain
antenna with a couple of broken ribs is a much better situation than having
to use the Low Gain antenna by itself.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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

Date: 3 Jan 93 13:43:00 GMT
From: Dave O <[e-mail]>
Subject: GOVERNMENT-RUN PROGRAMS
Newsgroups: sci.space

>But here's somethin to think about: did people lose interest and
the media reduced it's coverage in response, or did the media cut back
>coverage and convince people that they weren't interested in it?
>

I'd have to agree with you that media coverage can increase interest in
a particular topic - for instance, consider the plight of Somalia. I do
believe that NASA has not done a good job in promoting its own interest
in mass media lately. Our space endeavours could certainly spur the
imagination of voters today if the media was used as a tool of
inspiration, as it was in the '60's.

Dave O'Leyar
Energon Computing, Rochester, NY USA


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

Date: 3 Jan 93 15:12:55 GMT
From: Matthew Kaiser <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space

seems a kinda silly thing to think about to me..

it's like asking if i should leave my dorm room, or state
for any particular reason..

so much out there..
so many new things

my $0.02

matthew
[e-mail]

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

Date: Sun, 3 Jan 1993 14:40:37 EST
From: Graydon <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space

The Lunar advantage is mass, Henry.

If you want a 'hard' satellite, you can do three things - stealth it
(which is pretty ridiculous for a comsat, but not neccesarily for
a weapons platform), give it defenses (a hard problem), or armor it -
design the components to be rad hard, put it in a Faraday cage, and
wrap it in a lot of inert mass.  The Moon has a real advantage when
it comes to shipping inert mass to an Earth orbit, in terms of energy.
This doesn't do them any good unless they have a full industrial
economy there, though.

Taking out a radiation hard satellite with a nuclear weapon, particularly
one that is behind several meters of lunar regolith, isn't all that
easy - no blast effect means either a *big* bang is required (which will
annoy the people whose territory over which is was detonated, never
mind the commercial comsats), or a very close hit.  The very close hit
is basic orbital mechanics, but assumes no counter measures on the
launcher, launch site, etc.

This is all handwaving anyway, since a good analysis involves knowing
the launch costs from earth and the moon *after* that functioning
lunar economy gets put in place.  I'd *love* to have reliable
instances of such figures, truly I would.

Graydon

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

Date: 3 Jan 93 20:14:53 GMT
From: "James Borynec; AGT Researcher" <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

>How?  Earth-based antisatellite weapons are simple and cheap; anything
>in Earth orbit can easily be destroyed from Earth.  Unless you assume

Ok, I'll take that bet, blow up the moon.  It's certainly in Earth orbit.
By your argument it should be "easily destroyed".  I'll even let you
break a small sweat in your efforts.

I do not grant that current ASAT weapons would be effective against
"hardened" satelites.  We have never gotten into that kind of arms race
in any serious fashion.

I do know that transportation from the moon to LEO is about 25 times
easier than transportation from Earth to LEO.

The military tends to follow ther merchants.  A powerful moon colony
would have MUCH more at stake in the orbital sweepstakes than the
mother planet (with all of her unruly children).

j.b.

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

Date: Sun,  3 Jan 93 15:48:20 PST
From: Brian Stuart Thorn <[e-mail]>
Subject: Let's be more specific (was: Stupid Shut Cost arguement
Newsgroups: sci.space

>NASA is chartered as a research organization, not an operational agency.
>Shuttle is operations, not research.

    Shuttle is the only manned system we have, so it is in large part
    still a research article. I agree, however, that operations is
    the major part of the Shuttle system.

>>Pegasus as a current example of the effect of optimistic development
>>scheduling. That causes financial problems for a commercial venture
>>that government agencies can shrug off.
>
>However, DCX is on budget and has slipped very little (30 days in a three
>year contract). It looks like these guys know more than you about how
>do schedule launcher development.

    As Gary and I pointed out, Pegasus really started slipping after
    maiden flight... about eighteen months between flights 2 and 3, to
    be precise. That DC-X has slipped little prior to maiden flight is
    a good sign, but hardly justifies such smugness.

    -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: 3 Jan 93 23:15:29 GMT
From: Henry Spencer <[e-mail]>
Subject: lunar military position
Newsgroups: sci.space

In article <[e-mail]> Graydon <[e-mail]> writes:
>If you want a 'hard' satellite, you can do three things - stealth it...
>... give it defenses (a hard problem), or armor it ...
>...  The Moon has a real advantage when
>it comes to shipping inert mass to an Earth orbit, in terms of energy.

I'm sure the Moon colony would be the main supplier of armor for armored
military satellites.  That doesn't mean they'd own them, or that they
would have a monopoly on them.  Sure, it's more expensive to launch the
mass needed for armor from Earth, but it *can be done* -- the cost is
not prohibitive under the assumptions necessary for a lunar colony to
exist at all.  And the lunar colony is not going to be able to afford
Earth-sized military budgets for a very long time.  Their advantage,
while noticeable, is nowhere near enough to put them in a commanding
position over a much bigger and richer neighbor.

>Taking out a radiation hard satellite with a nuclear weapon, particularly
>one that is behind several meters of lunar regolith, isn't all that
>easy...

Direct hits are already-demonstrated technology.  You don't really need
nuclear weapons for this kind of thing; a direct hit from a ton of sand
will punch through that regolith layer pretty easily.  Knocking out
satellites is *easy* -- they can't maneuver very much (especially if
they're hauling many tons of armor around), reaching orbital altitude
is much easier than reaching orbital velocity (a Scud with suitable
guidance and course-correction systems would be a workable antisatellite
weapon), and their own orbital velocity makes warheads almost superfluous.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 3 Jan 93 15:49:05 GMT
From: Herman Rubin <[e-mail]>
Subject: Media and space
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Simon E. Booth) writes:

>Concerning public opinion about the space program, IHMO those opinions can
>and are greatly influenced by the media's depiction of space exploration.
>Next time watch news coverage of a shuttle flight.  Invariably some reference
>is made to the cost of that particular mission, plus any important technical
>information is either watered down or omitted.

>I've had people tell me that the media doesn't cover the space program very
>much because people aren't interested.

>But here's somethin to think about: did people lose interest and the media
>reduced it's coverage in response, or did the media cut back coverage and then
>convince people that they weren't interested in it?

How much interest SHOULD there be in any particular shuttle launch?  If we
had an adequate space program, there should be not much more interest than
in a trip of an ocean liner.  As the saying goes, "When man bites dog,
that's news."

Nor should anyone expect every observation made by a space probe to be
spectacular.  Any research program will have experiments or observations
made which are valueless; if we knew what we would find, it would not be
necessary to look for it, unless we can directly exploit it.

The first landing on the moon was quite properly a big media event, but
it is not at all surprising that the later ones were less so.
--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)
{purdue,pur-ee}!snap.stat!hrubin(UUCP)

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

Date: Sun, 3 Jan 93 14:02:24 -0500
From: [e-mail]
Subject: Poker Flat

> Does anyone know anything about "Poker Flats" in Alaska..
> Up near Fairbanks, AK.. If I remember right it is run by the
> University of Alaska Fairbanks.. Mostly does atmospheric (northern lights, et
>
> Michael Adams
> Alias: Morgoth/Ghost Wheel
> [e-mail]

    This is rather dated information but...10 years ago the University of
Alaska's Geophysical Institute operated the Poker Flat MST Radar.  It was
used to study tropospheric and stratospheric (below about 30 km) atmospheric
turbulence, winds, and waves, as well as mesospheric (around 85 km) echoes.

    Nearby related facilities (the Poker Flat research range?) were used to
launch rockets for mesospheric research, and track balloons to 30km for wind
profiles.

    More recently they have been involved in 'active' experiments using
rockets to release chemicals perturbing (temporarily and locally!) electron
and ion concentrations in the ionosphere.

    Also, I think I recall GI getting money from congress to build
a high latitude radar for ionospheric research.

    Anyway, I'm sure GI would be happy to send you a glossy brochure if you
write to them (Geophysical Institute, Univ. of Alaska, Fairbanks, AK 99701)
and I think they also have a quasi-periodic newsletter.

Steve

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

Date: Sat, 02 Jan 93 20:48:12 CST
From: Victor Laking <[e-mail]>
Subject: russian solar sail?+
Newsgroups: sci.space

>
> New one on me, but I have heard of the supposed race to the moon with solar
> sails, to celebrate the 500 anniversary of Columbus, not sure if it
> actually came about.. Maybe the olymbics will have a solar sale race or
> some other organization will have a solar sail race..
>
> ==
> ==
> Michael Adams alias Ghost Wheel/Morgoth [e-mail]

I know that there were some plans for an international "race" to Mars
with Canada, the US, Russia, and some other countries that I don't
remember.  The plan was to have each country make their own.
This way, the benefits of each design could be looked at.

Unfortunately, the project was canceled from what I have been told.
(I was talking to one of the NASA guys from sci.space.news about it.)
I seem to recall that the limiting factor that was mentioned was money.

Actually, using a solar sail to just go to the moon would be pointless as
they are only practical over a distance.  Remember, they use the solar
winds to carry them.  This means that they are going to take a long time
to build up a decent velocity.  However, over a longer distance, they can
be quite good.

Personally, I would like to see the use of solar sails catch on as a
method of travel.

If nothing else, it would be another case of sci-fi become fact.

[e-mail]
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607

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

Date: Sun, 3 Jan 1993 22:43:44 GMT
From: Henry Spencer <[e-mail]>
Subject: russian solar sail?+
Newsgroups: sci.space

In article <ida.725390192@atomic>, ida@atomic (David Goldschmidt) writes:
> I saw something a few months ago about a Russian plan to test a small solar
> sail from the Mir space station on Dec 10. of this year.  I haven't heard
> anything about it since - does anybody know if it happened?

Now scheduled for February, timing set by the timing of other activities
aboard Mir.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Sun, 3 Jan 1993 10:40:49 GMT
From: "Simon E. Booth" <[e-mail]>
Subject: SSTO vs 2 stage
Newsgroups: sci.space

The idea of a 2 stage DC configuration seems technically sound, but how
would it be compatible with the launch facilities designed around the
intended DC-vehicle (single stage)?

Could the service gantries and launch pads be designed to accomodate
different spacecraft configurations?  I know that the launch pads in use today
are built around the rockets launched from them (i.e. Pads 39 A and B can only
be used for the shuttle).

One possible use for a two-stage DC configuration might be a lunar flight
without having to re-fuel in LEO.


Unless I'm way of the mark again on this one.


Simon

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

Date: Sun, 3 Jan 1993 22:45:41 GMT
From: Henry Spencer <[e-mail]>
Subject: SSTO vs 2 stage
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Simon E. Booth) writes:
>The idea of a 2 stage DC configuration seems technically sound, but how
>would it be compatible with the launch facilities designed around the
>intended DC-vehicle (single stage)?

It wouldn't be, basically.  It would be a special configuration for
special needs, and would require special launch facilities.

>Could the service gantries and launch pads be designed to accomodate
>different spacecraft configurations?

It can be done, but it runs up the price, so it isn't done unnecessarily.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

End of Space Digest Volume 15 : Issue 628
------------------------------