Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_1/v15no196.txt

Internet Message Format | 1993-07-13 | 21KB

Date: Sun, 13 Sep 92 05:06:51
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #196
To: Space Digest Readers
Precedence: bulk


Space Digest                Sun, 13 Sep 92       Volume 15 : Issue 196

Today's Topics:
               Bioeffects of magnetic field deprivation
                          Leftover Martians
                        PHONE CELL SATELLITES

    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: 13 Sep 92 06:39:06 GMT
From: Jeff Bytof <[e-mail]>
Subject: Bioeffects of magnetic field deprivation
Newsgroups: sci.space

Since the beginning of the year I've been looking into some rather astounding
results offered by experimenters working in the area of the bioeffects
of magnetic field deprivation.  In view of the relevance to
manned lunar and interplanetary exploration and biological research,
I am posting the following information to sci.space and sci.bio.

I. Quote from "Proceedings of the Sixth Annual Meeting of the Working
   Group on Extraterrestrial Resources", NASA SP-177 (1968), page 6:

          "The possible biological effects of the low lunar
           magnetic field are not known, but recent studies
           summarized by Busby indicate that they may be
           significant.  In an experiment in which mice were
           raised in magnetically shielded cylinders, abnormal
           behavior, loss of hair, and early death were exhibited
           after the fourth generation..."

II. Quote from "Biomagnetics: Considerations Relevant to Manned Space Flight",
    by Douglas E. Busby, M.D., NASA CR-889 (1967), pp. 10-12:

          "...During the past 18 months, these investigators [M.H.
           Halpern and J.H. Van Dyke] have kept Swiss/Webster white
           mice and their progeny in mu-metal cylinders 8 inches in
           internal diameter and 24 inches in length, oriented in the
           East-West direction.  Mu-metal is an austentitic, nickel-
           iron-chromium-copper alloy of high magnetic permeability
           and low corrosion resistance.  The magnetic field intensity
           in the cylinders apparently remained well below the 100
           gamma level.  Control mice have lived in similar aluminum
           cylinders, which do not have an appreciable attenuating effect
           on the Earth's magnetic field.  The floors and end enclosures
           (inset one inch from the ends) of all cylinders consisted of
           non-magnetic, stainless steel, hardware cloth.  The cylinders
           and cages were intermixed and adequate temperature, humidity
           and ventilation of them insured.  The adult population
           of each cylinder was kept under 8 mice.

          "As pointed out in a preliminary, unpublished report, an
           unspecified number of originally four-month-old male and
           female mice were maintained continuously in mu-metal
           cylinders for periods of 4 to 12 months.  Each shield
           originally contained a single mouse family of one male and
           three females (Group I).  Data is not available on the
           number of mouse families this experiment was started with.
           First generation (F-1) mice litters were equally divided
           at weaning time (21 days), one-half (Group II) being
           retained in the mu-metal cylinders and the other half
           (Group III) being placed in the aluminum cylinders.  Group I
           females were continuously re-mated with their original males.

          "In contrast to the normally-thriving control mice in the
           aluminum cylinders, the mice in the mu-metal cylinders have
           presented a characteristic, rather bizarre picture.  Premature
           mating and frequent pregnancies have produced larger but
           apparently normal litters.  By the F-4 generation, repro-
           duction has usually ceased.  Unanticipated cannibalism and
           abortions of newborn mice has been encountered to a greater
           degree in the F-2 generation (and subsequent F-1 generations
           of the original animals) than in the F-3 and F-4 generations.
           At an early age, large numbers of mu-metal mice have become
           docile and inactive.  Many mice have exhibited the highly
           unusual behavior of lying on their backs for prolonged periods
           of time.  About 14 per cent of the adult population has
           developed a characteristic and progressive alopecia over the
           top of the head to at least half way down the back.
           Interestingly, there are no known mice which have the
           genetic trait of developing hair loss as adults.  Coarse hair,
           characteristic of aged mice, has also appeared at an early
           age.  Death has occurred prematurely, often as early as 6
           months of age.

          "Histopathological observations have been made on selected
           organs from 36 Group I mice.  Although the same manifestations
           were not always present in the same organs of all mice at
           the time of sacrifice, positive alterations, either grossly
           or microscopically, were apparent in most of the animals
           studied.  Connective tissue and epithelial tumors, which
           have frequently been found in various loci, remain to
           be studied further microscopically.

          "The skin has been found to be hyperplastic, but only in
           areas of alopecia, and characteristically has an undisturbed
           basement membrane, excessive mitotic activity in the basal
           layer, columnar-shaped granulosa cells, a hyperkeratotic
           stratum corneum, and hair follicle plugging with hyper-
           plastic squamous epithelium.  The livers of all experimental
           mice studied have shown the presence of hemosiderin crystals
           in the Kupfer cells to a variable degree.  In addition,
           liver tissue from these animals has clearly exhibited nuclear
           changes characterized by increased numbers and noticeable
           enlargement of their nucleoli, suggesting perhaps some
           alteration in the metabolism of ribonucleoproteins.
           Periperal blood smears showed very noticeable deposits of
           hemosiderin within polymorphonuclear leucocytes, and a very
           high incidence of reticulocytosis.

          "Most kidneys studied were polycystic to some degree, the
           cysts often markedly compressing adjacent cortical parenchyma.
           Many experimental mice, especially those examined after
           spontaneous death, had their urinary bladders distended with
           urine and apparently a white precipitate.  In at least a
           third of these mice, the bladder mucosa was markedly hyper-
           plastic, forming trabeculae and polypi.  The combined findings
           of the polycystic kidneys and bladder precipitate suggested
           that certain of these animals might have succumbed from uremic
           poisoning.  Notably, no bladder parasites have been found in
           either the experimental or the control mice.

          "The ovaries had numerous large, persisting corpus lutea,
           which often entirely encapsulated this organ.  Few follicles
           were in evidence, in spite of the high incidence of pregnancy
           in these animals.  In many mice, the uterus has been somewhat
           enlarged having numerous epithelial cyst formations in the
           endometrium.

          "Van Dyke and Halpern have pointed out that what they are
           observing in the mu-metal mice is a diffuse, hyperplastic
           condition.  They cannot foresee any possible cause of this
           condition other than the chronic exposure to the extremely
           low-intensity magnetic field.  It is suggested that a
           detailed evaluation of the protocols and conditions of
           this experiment should be made for the possibility of
           infectious, genetic or other factors being responsible for
           these unusual results.  At present [1967], none of these
           protocols have been made available to other investigators
           or this reviewer."

III. In January, I contacted Dr. Myron Halpern, now retired.  I
     questioned him about his experimental results.  I asked him
     about the possibility of mu-metal poisoning, which he held to
     be very unlikely.  The experiments ended in the late sixties
     when funding ceased.  The Apollo project was apparently satisfied
     that there were no problems with short-term (two week) exposure to low
     magnetic field strengths.  Halpern was adamant that his work
     had brought up many questions that remained unanswered and was
     anxious to see others do additional experiments to check his results
     and to determine the mechanisms by which the absence of a magnetic
     field would affect organisms.  Halpern still retains his mu-metal
     cylinders.

IV.  I next contacted researchers in NASA's Life Sciences Division at
     Ames Research Center.  One recalled an early short-term
     experiment with low magnetic fields, but there are no experiments
     ongoing or planned within NASA.

V.   A literature search came up with this title:

     "Magnetic Shielding Induces Early Developmental Abnormalities
      in the Newt, Cynops pyrrhogaster", M. Asashima, K. Shimada, and
      C. Pfeiffer (Bioelectromagnetics 12:215-224 (1991)).

     Quote of the abstract:

     "Developing larvae of the Japanese newt, Cynops pyrrhogaster, were
      subjected for 5 days to a shielded environment in which the static
      magnetic field was about 10,000 times weaker (5 nT) than the
      geomagnetic norm, which ranges between 30 and 60 micro Teslas
      at the earth's surface.  Larvae from non-cleavage to neurula stages
      were exposed under shielded or normal (control) conditions and
      then examined for evidence of developmental abnormalities either
      1 day or 20 days after treatment.  The magnetic shielding was
      associated with an increased incidence of somatic defects,
      especially in larvae that were examined 20 days after shielding.
      Bi-headedness and intestinal protrusion were observed in
      magnetically shielded larvae but not in controls. Other abnormalities
      more frequently observed in shielded larvae were spinal curvature,
      malformed eyes, and retarded or blocked development.  These data
      are among the first to illustrate the effects of magnetic-field
      deprivation on a developing animal."

VI. I wrote a letter to Dr. Makoto Asashima, Dept. of Biology, Yokohama
    University, one of the authors above.  He replied, "I have a plan
    to conduct more extensive low magnetic shielded experiments."
    They have a much different method of producing low magnetic
    fields than Halpern and Van Dyke.  They are using a magnetically
    shielded facility of the Japanese Institute of Space and Astronautical
    Science at Sagamihara.  I believe Dr. Asashima also has some
    responsibility for life experiments on the current or a future
    shuttle flight.

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

Jeff Bytof
[e-mail]

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

Date: 13 Sep 92 07:27:14 GMT
From: Nick Janow <[e-mail]>
Subject: Leftover Martians
Newsgroups: sci.space

[e-mail] (brad thornborrow) writes:

> I havn't been following the entire conversation here, but it seems to me
> everybody is missing the gravity problem.  Last time I checked, Mars' gravity
> was not strong enough to keep oxygen molecules from escaping into space over
> time.  So, even if one could start plant-life on Mars, you'd have to have a
> heck of a lot of it to keep the oxygen from just "floating away"!!!

The reference material I have says that Mars can lose oxygen through
non-thermal means (such as splitting ozone), but it doesn't seem to indicate a
very fast loss mechanism.  The oxygen is replenished by the photodissociation
of water and the loss of that hydrogen.

Actually, life on Mars evolved to handle the loss of oxygen partial pressure.
They grew silica terrariums enclosing photosynthetic material, air and water.
During the day, it turns the CO2 into O2; at night or when covered by sand, it
utilizes the stored O2.  As the surface conditions worsened, the plants growing
the tallest silica projections (light pipes) survived.

Now, the bubble plants live deep beneath the surface, with roots that dig into
the permafrost layer.  Some plant colonies store the air in deep chambers, so
that the loss of leaves (air bubbles) to sandstorms is not so critical.  In
fact, the loss of those air bubbles is their form of propagation; bubbles
immediately start forming roots and fibres, hoping to form a link between water
ice and light before their reserves run out.

Now, what about predators...   :-)

--

[e-mail]

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

From: Nick Szabo <[e-mail]>
Subject: PHONE CELL SATELLITES
Newsgroups: sci.space

Message-Id: <[e-mail]>
Date: 13 Sep 92 06:30:15 GMT
Article-I.D.: techbook.1992Sep13.063015.19520
Organization: TECHbooks --- Public Access UNIX --- [phone]
Lines: 149
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]


PHONE CELL SATELLITES

Current cellular phones use a network of thousands of ground-based
towers each projecting a radio "cell" a few miles across.  Service is
largely limited to cities in developed countries.

Phone cells can greatly expand this service, while developing the
critical technology of miniature spacecraft components for the 21st
century.  The biggest markets are travellers and wealthy third worlders,
who number 10's of millions despite being a small % of the total -- in
Russia, India, China, Brazil, Mexico, Iran, Indonesia, Thailand, Turkey,
Eastern Europe, etc. that have no cellular service.  Cellsats can also
usefully serve international air and ocean lines.   At least initially,
it won't compete with existing cellular service.  The market is
universally (well, globally :-) available cellular service, at a higher
cost.  How much higher depending on how many people sign on...the old
chicken & egg story.  If everybody signed on, it would actually be much
cheaper than the current local cell system, but these companies do not
count on that to happen initially; the systems can pay for themselves
by opening new niches.

The cost of the most publicized system, Iridium, is projected at
$3 billion.  If one out of every five thousand people on our
planet make $300 worth of phone calls a year for ten years, the
system pays for itself.  Initially this would be mostly business,
not personal use (as was the case for city cellular when
it started out).  For this market the price will be about twice as
high as the current city cellular.  If the market expands well beyond
1/5,000 of the world population, the price can go below that of current
urban markets, supplanting the thousands of towers with a more efficient
set of radio cells projected from space.   Concievably, with
an expanded set of satellites the price of cellular service could drop
well below the price of current international long distance, replacing
GEO satcoms altogether for this $10 billion/year market.  Initially, the
technology will be quite properly marketed at the 90% of the
Earth's surface currently without cellular service.

IRIDIUM

Here are the Iridium specs.  Note that the constellation has
been redesigned for larger satellite and cell size, reducing
the number of satellites from 77 to 66:

satellite: 386 kg
user handset: 3 lbs
voice,data,fax
digital & encryptable
global digital switch network
markets:
- general aviation and business aircraft
- maritime communications
- rural, Eastern Europe & Third World locations
$3/minute
- 1/2 to local providers
- 1/2 to Iridium members
370 mi. dia. cell * 37 * 11 * 7 (100K mi.^2)
66*4 cross-link antenae, each 20 Ghz
adjacent planes move in opposite directions

Some tasks the Iridium people are working on:

* Building the satellites.  Since the scale is small, new technology
can be incorporated and tested with small risk.  Thus, there is
no need to stick with old electronic technology used in the larger
GEO satcoms.  Lockheed will be in charge of developing the satellite
bus and choosing the launcher.  Motorola will develop the communications
payload and make and market the cellular phones.

* Choosing a launcher capable of boosting test and replacement
satellites into their unique orbits for less than $10 million,
as well as a launcher for the main satellites, from one to seven
at a time, for less than $8 million apiece.  Currently Pegasus
costs $10 million and fits the first bill, although with only one
good launch under its belt it needs to prove its reliability.
Delta or Atlas launching Iridium in groups of 6 could fit the
second bill, and a rumored Russian competitor to Pegasus might
be able to launch singlets for less than $8 million.  OSC needs
to finish the Pegasus' hydrazine stage to improve the orbital
insertion accuracy.  The development of Pegasus' low entry-level-cost
capability was a main driver behind the inspiration and genesis of
Iridium and several other emerging small satellite industries.

* The Iridium Consortium must obtain a set of frequencies in all
the countries in which it wants to market its service.  Phone
cell satellites have obtained frequency from WARC and now each
proposal must compete at national government levels.

* New members must be added to the Iridium consortium; Motorola and
Lockheed probably won't pay all the $3 billion on their own.
The finance folks are busy talking to people like AT&T, NTT,
and dozens of other deep pockets.  Whoever puts in the most money
could very well gain control over the world's cellular phone
industry.

GLOBALSTAR

This information is from Klein Gilhousen of Quallcomm, Inc., which is
teamed with Loral and several European companies on Globalstar:

There will be 24 satellites in LEO (750 nm) in the initial deployment
with coverage optimized for the U.S.  Later, when international agreements
are in place, the constellation will be expanded to 48 satellites, providing
global coverage and improved coverage and capacity over the U.S.

The system uses NO intersatellite relays.  (I believe that these relays
are a prime cost driver of the Motorola approach and that they would
solve a non-existent problem.  The problem is to connect mobile users
into the network.  Period.  Global routing of phone calls is something
that we already have.)  By virtue of have no crosslinks, the satellite
is significantly smaller and cheaper than the Iridium system.

Total launch mass of one satellite is 262 kg.  Eight satellites would be
stacked and launched at once by a Delta, Ariane, or other standard
launch vehicle.

Airtime charges are projected to be in the same range as cellular
service.  According to the filing, initially, the airtime would be
$0.31/minute with a monthly access fee of about $24.  Later on, charges
would fall to about $0.22/minute.

The mobile phones will be based on CDMA digital cellular phones with
RF adaptors to make them work in the L and S bands of the satellite
system.  Thus, the cost would be that of a CDMA cellular phone, plus
maybe 10-20 percent for the adaptor.

The system would offer call capacity comparable to that of the Iridium
system's satellite network with many fewer and less costly satellites through
the use of the CDMA technology.  Because a much smaller investment is
required, the service cost will be correspondingly smaller.

CONCLUSION

Thinking small -- thinking at the optimum economical scale of
technology, instead of the idealistic scale of technology --
is one of the major paradigm advances of phone cell satellites.
The Iridium and Globalstar breakthrough is a good example of why
industry is needed to set the standards for space technology,
instead of government dictating to industry.  Private industry
is far more in tune both with the advance of technology and
the needs of people.  Government civilian programs have practically
ignored -- spent less than 1% of their budgets on -- the technology
needed for this lucrative market.  Private industry is putting up
its own money to fill this gap.


--
[e-mail]        Tuesday, November third  ##  Libertarian  $$  vote
Tuesday  ^^ Libertarian  --  change  **  choice && November 3rd @@Libertarian

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

End of Space Digest Volume 15 : Issue 196
------------------------------