Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_2/V15NO201.TXT

Internet Message Format | 1993-07-13 | 33KB

Date: Tue, 15 Sep 92 05:00:33
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #201
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue, 15 Sep 92       Volume 15 : Issue 201

Today's Topics:
                          Asteroid explorer
                  Clinton and Space Funding (3 msgs)
         Is NASA really planning to Terraform Mars? (2 msgs)
                     NASA working on Apollo rerun
             Old data formats (was New lunar spacecraft)
                            overpopulation
                            RL-10 (2 msgs)
             Shuttle Replacement (was: One Small Step...)
                        Solar Ram Jet (2 msgs)
                   Terraforming needs to begin now
                           Who went to Rio?
         With telepresence, who needs people in Earth orbit?

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

Date: 14 Sep 92 14:04:30 GMT
From: Curtis Roelle <roelle@uars_mag.jhuapl.edu>
Subject: Asteroid explorer
Newsgroups: sci.space

Path: uars_mag!roelle
Date: 14 Sep 92 13:26:42 GMT
Message-ID: <roelle.716477202@uars_mag>
Newsgroups: sci.space
Subject: Re: Asteroid explorer
Distribution: usa
References: <[e-mail]> <[e-mail]>

[e-mail] writes:

>I along with Dr. Higgins saw an awesome presentation at the WSC about a
>faster cheaper better asteriod mission that boggles the mind.  Launched in
>98 it would go out to a near earth crossing asteriod, (I forget which one) and
>actually go into orbit about it. (it is a small one less than 20 miles in
>diameter)  Then after several months it would leave orbit, do a lunar swingby
>and go out into the belt for a weird grand tour that ends up at Eros in 2008.
>To top it off you get a couple of comets tossed in for free!  I wonder if Bill
>bought the paper on that one.  It was from JPL and was a laugh a minute as
>this guy tossed out several variations of the mission that would take the
>probe to several asteroids and comets.  He spoke in the manner of a vacuum
>cleaner salesman and although he was funnin, it was a joy to hear.  Anything
>to add there Bill?  BTW Bill send me a message I need your snail mail address.

>Dennis, University of Alabama in Huntsville

Might you possibly be refering to Robert Farquar of the JHU Applied Physics
Laboratory (APL).  His style of presentation matches your description.  He
was behind the 1985 Interplanetary Cometary Explorer (ICE) mission to Comet
P/Giacobini-Zinner, which included something like two earth gravity assists
and five from the moon.  He's currently involved with the Near Earth Asteroid
Rondezvous (NEAR) mission (Forgot which asteroid -- the target changed a
couple  months back).  The NEAR spacecraft will orbit the asteroid at
various stand-off distances.

Farquar presented a plan at last year's Montreal meeting of the IAF which
proposed launching dual spacecraft in 2003, arriving at Comet P/Encke
four months later.  Following the Encke encounter both spacecraft
would use Earth gravity-assist maneuvers to reach other targets.  S/C 1
would encounter P/Schwassman-Wachmann-3 in 2006.  S/C 2 is retargeted
to rendezvous with 433 Eros in 2005.

These types of missions are relatively cheap.  The ICE mission was a new
name given to the International Sun Earth Explorer (ISEE-3) spacecraft.
Farquhar keeps his eye open for unused spacecraft at or near the end of their
missions, that he can play billiards with, shooting bank shots about
the solar system.  Parents, do you know where your spacecraft is?

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

Date: 13 Sep 92 18:28:00 GMT
From: Mark Goodman <[e-mail]>
Subject: Clinton and Space Funding
Newsgroups: sci.space

Reply-To: [e-mail]

Gerard Vignes writes:

>        We all know those are empty campaign promises,
>        but we also know that Clinton and Gore are
>        hostile to technology and research spending
>        and especially to projects involving
>        space exploration and astronomy.

You may presume this to be true, but you certainly do not _know_
it.  Judging by their statements, precisely the opposite is true.
You would be hard pressed to find a stronger or more knowledgable
supporter in Congress of research and technology development than
Al Gore.

Henry Spencer writes:

>Of particular note is that John Pike reportedly has major input to their
>space positions and is likely to be head of the Space Council staff if
>C/G are elected.  He basically opposes manned spaceflight and does not
>believe that cheaper launch vehicles (e.g. SSTO) are possible.  Or so I
>am told; those who get to vote in this election might wish to investigate
>further if you care about the future of spaceflight.

John Pike has been a big opponent of military space boondoggles
(SDI), but a big supporter of human space exploration.  His skepticism
about cheaper launchers is based not on hostility to the idea but on
history, as one vehicle after another failed to live up to predictions.

The key to the future of NASA lies with its new Administrator, not
with the next administration.  To vote for President in this
election on the basis of space policy issues is silly, since the
candidates hardly differ.  To urge people to vote on that basis is
irresponsible and dishonest.

Mark W. Goodman

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

Date: 14 Sep 92 08:53:25 GMT
From: Paul Leyland <[e-mail]>
Subject: Clinton and Space Funding
Newsgroups: sci.astro,sci.space

In article <[e-mail]> [e-mail] (Vignes Gerard M) writes:

       Bill Clinton claims he will cut taxes,
       balance the budget, and increase social spending.

...

       If you've not yet done so,
       please register to vote.
       There's still time.

Can you tell me how to register to vote in the US election please?

       When election day comes,
       please get out and vote.
       It's your right AND your duty.

I'd love to 8-)

       Don't stay home that day just because you're disgusted,
       and let a pitifully small percentage of people
       determine our nation's future.

*Your* nation's future.

Paul

P.S.  sci.astro goes to a lot of non-US people you know.

P.P.S. Please don't take this as anything other than tongue-in-cheek.
I just posted an article about proposed UK legislation which impinges
on the light pollution problem.
--
Paul Leyland <[e-mail]>          | Hanging on in quiet desperation is
Oxford University Computing Service      |     the English way.
13 Banbury Road, Oxford, OX2 6NN, UK     | The time is come, the song is over.
Tel: [phone]  Fax: [phone] | Thought I'd something more to say.

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

Date: Mon, 14 Sep 92 12:26:12 BST
From: [e-mail]
Subject: Clinton and Space Funding

>     A non-vote is not a form of protest;
>     it's a clear signal that you're happy with things
>     just the way they are and you really don't care anyway.
>


And if you find that Bush/Quayle also makes you want to throw up,
there is Andre Marrou/Nancy Lord on the Libertarian ticket. Be
anti-fascist and pro individual liberty.






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

Date: 14 Sep 92 08:39:16 GMT
From: [e-mail]
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

In <[e-mail]> Thomas H. Kunich writes:
>In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>>I've always wondered about logic like this.  I suppose the increasing
>>population in sub-saharan Africa to going to stabilize politics thus
>>making food available?  Sure.  Makes sense to me.
>This is the point I've been listening for. It really doesn't matter what
>the reasons for starvation are. It is happening.

  Au contraire .. It very much _does_ matter what the reasons are. It
is not possible to devise a long term solution to a problem, if you
don't understand what the problem is, or are attempting to solve the
wrong problem.
 -----------------------------------------------------------------
               ** Of course I don't speak for IBM **
Greg Nicholls ... [e-mail] or [e-mail]
                  voice/fax: [phone]

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

Date: Mon, 14 Sep 92 14:35:46 GMT
From: Doug Mohney <[e-mail]>
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Thomas H. Kunich) writes:
>In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:
>>
>>I've always wondered about logic like this.  I suppose the increasing
>>population in sub-saharan Africa to going to stabilize politics thus
>>making food available?  Sure.  Makes sense to me.
>
>This is the point I've been listening for. It really doesn't matter what
>the reasons for starvation are. It is happening.

Garbage. Ignorant hand-waiving garbage. If you want to provide a solution, you
have to know the causes.

In Ethopia, we would have had to overthrow the (Communist) government and
create a new one. In Somalia, we'd have to hunt down all the warring factions
and install a military presence.

Will you two volunteer to be in the army? Kill people in order to feed
villages. That's about what it takes.

Your arguments are flawed. The fundmental problem is that starvation is caused
by thugs and roving gangs. Period. It is NOT caused because the food has run
out, as the POINT to you which all the Club of Romers seem to think.

>>I see, so In ten years, all those green technologies the crazy tree huggers
>>have been working on are going to be suitably conservative for you to use?
>
>Ten years won't be enough time for the political force to be generated
>to spend the money to build these energy resources on a large wnough
>scale. I am afraid that by the time it it plain enough to the man on the
>street it will already be too late to start.

Oh pleaseeeeee. You patronizing bunch of know-it-alls. As soon as oil becomes
too expensive, other substitutes will become available.

>This whole string relates to space. (Believe it or not) This is
>because a space faring species is one with energy independance of
>a large order. We are who we are mostly because of the cheap and
>plentiful energy storage that mother nature was so kind to
>leave laying about. This has turned out to be even more plentiful
>then believed in the 50's but is, nevertheless, of a finite nature.
>
>There _are_ means and methods that could greatly reduce the impact
>of a petroleum-less society, but most of these need to be financed
>heavily and soon.

No. We do not. We do not need a Manhatten-like crash project to get rid of oil.
When the price of oil rises enough to discomfort people, other forms of energy
will become price-competitive. It is a simple economic truth.

The Carter administration tried to fund the synthetic fuels in the late '70s.
Ended up being a big waste of money because the price of oil got cheaper,
rather than more expensive. Plus the waste and inefficency of a
goverment-dictated solution.

> The political enertia of the world's governments
>and the staggering global debts may simply make it impossible for
>the required steps to be taken in time for any meaningful corrections
>to be made.

If the problem is that horrible, you declare war and usurp resources. When you
declare war, you don't worry about debt but do you damnedest to win by any
means necessary.

The (alleged) problem is not that bad.

If we really really needed to, we could rebuild a heavy lift vehicle, and
launch power-sats within ten years.

No, I am not kidding.

We got to the moon within 10 years from ground zero. We have the knowledge
base from those experiences. We will build a space station within 10 years on a
slow boat and tight budget.

If the problem was really really really really bad, we could purchase heavy
lift from the Russians and put up our first power sat within 5 to 7 years.

IF we needed to. If the money and need was there.


                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: Mon, 14 Sep 92 14:57:03 GMT
From: Doug Mohney <[e-mail]>
Subject: NASA working on Apollo rerun
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Nick Szabo) writes:

>The missions would have a crew of four instead of a crew of three, in
>an enlarged Apollo-style capsule.  The craft would land directly on
>the surface instead of doing Apollo's lunar-orbit rendesvous, increasing
>costs but allowing the craft to land at lattitudes higher than the
>equator.  The system requires -- get this -- a launcher 1.5 times the
>size of Saturn 5!

Actually, the reason given was you could hit any interesting point on the Moon
with a direct launch.

>The function of these missions is an extension of Apollo.  Geology
>treks using an Apollo-style rover (again made larger to hold four
>astronauts) would be the main justification.

It's important to know what what's there before you mine it.

> They would try out
>tiny experiments in making LOX and lunar soil bricks, as a sop to
>those who want a real lunar base.  No production plants, no
>mass driver, and no biosphere.

You build small to test concepts. Could you show me a company which didn't test
all of its concepts, then built a pilot plant? Followed by a full commercial
plant. Get real.

> Most time at the "base"
>would be spent by the astronauts huddled in their capsules,
>studying each other.  There would be no revenue or commercial
>interest in the project.

None have been solicited or offered.

>No estimate of cost was given, and perhaps none is needed, given
>the political unviability of the project.  The project requires
>a new upper stage, a new habitation capsule, a new 4-propellant lander,
>a new rover, new spacesuits, along with the various experiments.  They
>propose a monster rocket 1.5 times the capability of Saturn 5, which
>would not be used by anybody outside NASA.  Thus, I would give a
>conservative guestimate of the cost of Apollo plus the cost of SSF,
>or $270 billion.

Well, you're full of it. Golden et al are VERY price sensitive. This is all a
moot point since Congress won't even fund something like the Lunar Resource
Mapper.

> In an attempt to mollify Congress, NASA proposes
>to take the money out of other NASA projects, but this cost

Your estimated cost (Done by the Shezer Accounting Method: If it's not my baby,
we make it look as big as possible).

> is 19
>times the entire annual NASA budget, and NASA already admits to having
>more projects than it can fund. NASA has already cut the planetary exploration
>budget down to $300 million per year, one-one-thousandth (1/1,000) the
>cost of this project to study the geology of one body.

Sure. The one body we KNOW we can get to and work on.

>  No doubt clever
>accountants will give us a lower number in an attempt to make the project
>politically viable, but that number will deserve a critical look.

Now you're condemming it before seeing ANY real price figures. Can you quote
any NASA official on a price tag yet or are you going to wave around billions
and billions of dollars?

                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: 14 Sep 92 10:22:11 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Old data formats (was New lunar spacecraft)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Frederick A. Ringwald) writes:
> NASA has implemented a highly cost-effective science program to mine
> overlooked gems from old astronomy satellites, called the Astrophysics
> Data Program (ADP). This program funds preservation of old data sets
> and updating them into new formats, as well as science.
>
> So, isn't there also a corresponding program for archival data from old
> planetary science probes? It's worrisome that no one in sci.space came
> up with its name - does this mean such a program does not exist?

Not that I know of.  This would be a good question to ask the folks at
the National Space Science Data Center or the Lunar and Planetary
Institute.

I did meet somebody at the World Space Congress who was involved in an
informal effort to recover the Lunar Orbiter data.  The data are
stored in analog format on magtapes.  They've located a machine which
may be capable of playing them back, but nobody knows whether the
tapes are in good enough shape to read all the pictures.  The hope is
to get the data into nice digital form so modern computers can digest
them.  There are at least two serious lunar-mapping spacecraft
projects underway in the U.S., and at least one in Japan, so there is
real interest in access to these pictures.

I didn't ask exactly where the tapes are.  LO was a NASA Langley
project, but I don't know where the data-management end was.  A
reasonable guess would be that there is at least one set at NSSDC at
Goddard.

As Dennis Wingo has pointed out, the pictures are also available on
microfiche from the Planetary Image Facilities.

Bill Higgins, Beam Jockey              | "I'm gonna keep on writing
Fermi National Accelerator Laboratory  | songs until I write the song
Bitnet:           [e-mail]  | that makes the guys in
Internet:       [e-mail]  | Detroit who make the cars
SPAN/Hepnet:           43011::HIGGINS  | put tailfins on 'em again."
                                            --John Prine

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

Date: Mon, 14 Sep 92 14:45:41 GMT
From: Doug Mohney <[e-mail]>
Subject: overpopulation
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Josh 'K' Hopkins) writes:
>[e-mail] (Don Roberts) writes:
>Fine.  So it's their fault.  That makes everything OK.
>
>I actually thought the post was reasonable, factually based and quite rational
>until I came to this line.
>
>>The trick is technological and economic development, not forcing
>>Africans at gunpoint not to have babies.
>
>Coments like this blow me out of the water.  Yes, making everyone a first world
>citizen is the long term solution, but you can cut growth drastically without
>using guns.  Contraception is _not_ available in Africa.  A very large
>percentage of women would prefer to have fewer children if that was an option.

<chuckle>. Some very BROAD statements. Which part of Africa do you refer? There
are some countries which are quite "civilized." Why, they even have running
water and color TV in the cities!

Furthermore, the traditional Third-World family has more children because it's
the only "resource" it can produce. More hands means more workers. And more of
a chance for someone to take care of you when old age comes along. Less chance
of having your whole family wiped out by disease or starvation.

>Given that population growth negates much of the progress made by foreign aid
>shouldn't we be encouraging family planning rather than giving out short term
>help?

We are. Both Planned Parenthood and the World Health Organization have programs
to get family planning information out to "poor" countries. No big secret. It's
been done since the '70s, with varying results.

                 Play in the intelluctual sandbox of Usenet

  -- >                  [e-mail]                        < --

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

Date: Mon, 14 Sep 92 12:55:40 BST
From: [e-mail]
Subject: RL-10

> The first one was thought to be ice, or something, in the turbopumps
> interfering with startup.  I haven't heard any verdict yet on the second
> one; I know they were taking pretty stringent precautions against pump
> contamination in the wake of the first one.
>

One of the oldest tricks in the book :-) Similar problem made Gary Hudsen's
Percheron test flight into a lovely on the pad firecracker back in 1980 or
so. Water ice is the bane of all cryogenic engines.


Also a comment on the failures cited for various old ICBM's. The statistics
stated so far tell me little about the failure rate of RL-10 engines. Serious
failures are followed by booms because the RSO decides to MAKE them go boom.
Just because a few Centaurs have failed over 25-30 years, doesn't say much of
anything about the engines themselves. If a tank ruptures, a flight computer
glitches, or any of a thousand other things occur that have nothing to do
with the RL-10, an RSO will push a little button.

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

Date: 14 Sep 92 13:35:54 GMT
From: Gary Coffman <ke4zv!gary>
Subject: RL-10
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>On Atlas' first flight, June 11, 1957, it went boom. On Atlas-Centaur's
>>first flight, May 8, 1962 the Centaur went boom....
>
>Sure they go boom. If one does, the crew will die. If you have
>a problem with that, we can all be thankful that you whern't
>around in the early days of avation.
>
>For the state of the art, they are a hell of a lot more reliable than
>aircraft where at a similar time. That's good enough.

As I noted in the part you deleted, after 30 years they are still going
boom. After 30 years, the Wright Flyer was replaced by the DC-3. There's
a limit to how many times you stretch old designs before you get out a
clean sheet of paper and start over. Atlas, Delta, and Titan are well
past that point. Instead of stretching them again, it seems better to
me to start with a new design for a HLV, one that employs lessons learned
about rocket propulsion over the last 40 years.

Gary

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

Date: 14 Sep 92 13:02:12 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Shuttle Replacement (was: One Small Step...)
Newsgroups: talk.politics.space,sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:

>So instead you want to stretch designs, Titan and Delta, that are
>already 30 years old one more time.

1. The designs in question all have safety factors of 2.0; nothing
   is being stretched anywhere.
2. The existing Titan and Delta are very different from what they
   where 30 years ago. 30 years of continuous improvement will do
   that.

>No thanks. We can count on
>general technology advances in the next 12-35 years that will allow
>us to build something *better* than those roman candles when we
>actually *need* them.

Except that we can't do the research to develop this technology because
people like you have made a virtue out of wasting money on the existing
systems.

    Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------222 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Fri, 11 Sep 92 07:53:36 PDT
From: Jim Bowery <[e-mail]>
Subject: Solar Ram Jet
Newsgroups: sci.space,sci.aeronautics

Ron Peterson writes:
>I'd like to know if it would be possible to build a micro-sized
>platform that could lift itself in the air powered by a solar cell
>or very small battery.  I thought that perhaps a tiny ion motor
>with a solar cell painted on its exterior might be capable of
>lifting itself off the ground.

You're on to a very interesting idea here.  Since solar flux is
about a kilowatt and you need about 50 watts per kilogram "work rate"
to overcome gravity, some scheme for turning solar energy into
thrust might be workable.  If a derivation of ion engines could
use rarified gasses in the upper atmosphere as reaction mass, the
implications could be profound.

A related idea is a solar ram jet.  I haven't really given this much
thought but it is probably good enough for science fiction:

The basic principle is that energy efficiency of a thruster is
inversely proportional to its exhaust velocity due to the velocity^2
term of kinetic energy vs the velocity^1 term of the mass flow rate
equation.  You'd like infinite reaction mass to throw away at almost
zero delta velocity to have the ultimate in thruster efficiency --
something like walking.

Therefore, a thruster that can entrain a large mass of air relative
to its weight, say a simple cylinder ala ram jet, do little to impede
the air passing through it and and then add a small velocity to it
through thermal expansion from solar heating might be able to sustain
itself in flight especially if the cylinder walls can be made light
enough, transmissive enough on the sun-side and black-body-radiative
enough on the shadow side.  It would probably end up looking more like
a blimp than a ram jet engine and would need a lot of help getting
off the ground.  The circular shape might have to be modified to make
the "engine" into a lifting body as well.

If such a craft achieved Mach 1.1, it could sustain itself
in flight indefinitely by exactly countering the earth's rotation
and always staying where it is "noon".  With such a simple structure
and no moving parts, reliability wouldn't be much of a problem.  Throw
in some tethers to pick up and leave off payloads and you have a system
that pimply-faced boys with crushes on budding econazi girlfriends might
like to read about in Analog.

--
INTERNET:  [e-mail] (Jim Bowery)
UUCP:   ...!ryptyde!netlink!jim
NetLink Online Communications * Public Access in San Diego, CA [phone]

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

Date: Mon, 14 Sep 1992 15:06:58 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Solar Ram Jet
Newsgroups: sci.space,sci.aeronautics

[e-mail] (Jim Bowery) writes:

... Throw
>in some tethers to pick up and leave off payloads and you have a system
>that pimply-faced boys with crushes on budding econazi girlfriends might
>like to read about in Analog.

First, less seriously: Jim, stop the personal attacks, it does
nothing useful. I'm not pimply faced and I don't read Analog.

Second, I don't think there are any budding econazis around under
the age of 10. By 11 I think they're all at the pro level...

;-(
--
Phil Fraering [e-mail] where the x is a number from 1-5.
Phone: [phone] SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560

           --> Support UN military force against Doug Mohney <--

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

Date: 14 Sep 92 08:55:13 GMT
From: [e-mail]
Subject: Terraforming needs to begin now
Newsgroups: sci.space

In <[e-mail]> [e-mail] writes:
>Ahh. I might point out that someone already owns the outback so it
>might be nice to ask them first. Not that anyone often bothers to ask
>the Australian aborigines what they want. I got an earful from one
>with whom I reached a state of Irish nirvana with (ie we didn't keel
>over until 7am)
 This keeps cropping up among the uniformed. Let me see if I can
phrase this succinctly. Parts of OZ are privately owned, the rest is
crown land. That means it is owned by _all_ Australians, not just by
 a minority group. The Aboriginies do _not_ , except in their
imaginations, own Australia any more. They ceased to own it some
200 odd years ago. They are one small part of a multi-cultural society,
and they're going to have to accept this fact and learn to love it.
  Guilt trips over events which happened hundreds of years ago, under
far different conditions than any of us can understand, serve no
useful purpose.
 -----------------------------------------------------------------
               ** Of course I don't speak for IBM **
Greg Nicholls ... [e-mail] or [e-mail]
                  voice/fax: [phone]

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

Date: 14 Sep 92 11:45:46 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: Who went to Rio?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Patrick Chester) writes:
> I'll make this brief. I just would like to know if any spaceflight advocacy
> groups like the L-5 Society or the Lunar Society made it to the Earth Summit
> in Rio last June. I was hoping someone tried to inject some other views on
> saving the environment there (like moving some industry off Earth and getting
> resources from the asteroids, etc.) Just wondering.

To my knowledge, no.  I think I have a fair chance of having heard
about it if any such people had attended the Rio summit.

There does seem to be a sizable community of international users
interested in remote sensing from space and its application to
environmental problems.

At the moment, "moving some industry off Earth," as a method of
"saving the environment," must be viewed as pure science fiction.
Industries which have been moved off Earth to some extent have
replaced microwave relay towers, submarine cables, radio navigation
transmitters, and reconnaissance aircraft, none of which contribute
much to the environmental strain humans place on our planet.

     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [e-mail]
   -   -       Internet:  [e-mail]
     ~         SPAN/Hepnet:      43011::HIGGINS

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

Date: 14 Sep 92 10:44:39 GMT
From: Bill Higgins-- Beam Jockey <[e-mail]>
Subject: With telepresence, who needs people in Earth orbit?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Thomas Clarke) writes:
> In article <[e-mail]> [e-mail]
> (Roger Arnold) writes:
>> It's absurd to tie teloperation in low earth orbit to a communication
>> path involving two round trips to Clark orbit.  Build a necklace of
>> co-orbiting microsats to relay signals from the facility to whichever
>> satellite is currently in position to downlink.
>
> Easier still, use the Motorola Iridium constellation of 77
> satellites for teleoperation.  Iridium should work just as
> well for LEO as for "cellular phones" on the ground.

Almost true.  I talked to one of the Iridium team, Dr. Peter Swan,
about this after sci.space discussed this point last fall.

If I understood him correctly, the Iridium satellites will have
down-pointing antennas covering overlapping cells on the ground.  At
altitudes above the ground, the antenna beams from adjacent satellites
won't necessarily overlap.  Think of each satellite as riding on top
of a big cone with its base on the Earth's surface.  People on the
ground are always inside at least one cone, but spacecraft a few
hundred miles up may break through the wall of a cone and be between
cells for a while.

Swan said that short-duration Iridium calls might be possible for
spacecraft orbiting lower than his satellites, as long as the
spacecraft took responsibility for managing its own antenna-pointing
to stay in touch with the Iridium network.  We were discussing this in
the context of a spacecraft doing brief data dumps to Earth.  You
could run a small scientific satellite or packet BBS this way without
having to maintain an elaborate downlink network.  It would be like
some of the Amsat satellites, without benefit of hams.  Maybe we could
call it Phreaksat.

This doesn't sound as though it could be adapted to teleoperation very
well, except for brief periods, unless there is a good way to solve
the problem of interruptions. (I have an image of our telepresence
operator frantically pumping dimes into an Iridium handset to prolong
contact during some crucial task...)

Also note that if you're using Iridium for teleoperation-- let's say
you're driving a bulldozer in Antarctica from your office in Florida,
or vice versa-- your delay may change as the moving cell
configurations give you a variable number of hops in your signal.  (I
could be wrong about this.)

Bill Higgins          |  If we can put a man on the Moon, why can't
Fermilab              |  we put a man on the Moon? -- Bill Engfer
[e-mail] |  If we can put a man on the Moon, why can't
[e-mail]   |  we put a woman on the Moon? -- Bill Higgins

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End of Space Digest Volume 15 : Issue 201
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