Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V13_0/V13_035.ZIP/V13_035

Internet Message Format | 1991-06-28 | 18KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/MbXqDIa00VcJQHYk4l>;
          Sat, 12 Jan 1991 14:30:33 -0500 (EST)
Message-ID: <[e-mail]>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Sat, 12 Jan 1991 14:29:22 -0500 (EST)
Subject: SPACE Digest V13 #035

SPACE Digest                                      Volume 13 : Issue 35

Today's Topics:
           Re: Humankind's Second Off-world Colony
            Re: shuttle was answer
    SPECIAL SOLAR TERRESTRIAL BULLETIN AND STRATWARM ALERT UPDATE
          Re: LOX/LH2 in Shuttle Payload Bay
          Re: Umbra (eclipse shadow) satellite photo
        Re: space news from Dec 10 AW&ST (TIRE DAMAGE)
           Re: Humankind's Second Off-world Colony
               Salyut orbital elements
              HSTMAP for IBM PC

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: 9 Jan 91 22:40:22 GMT
From: swrinde!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!news.cs.indiana.edu!maytag!watmath!watdragon!watyew![e-mail]  (Brian or James)
Subject: Re: Humankind's Second Off-world Colony


    Local power supply on Jupiter's moons? I've seen models
of Europa that give it liquid water under a shell of ice. Perhaps
a heat engine pumping heat from the water to the surface of Europa
could be set up?

    I have this bad feeling the ice is inconveniently thick, though.

    Gee, Jupiter has that big magnetic field. How about using *that*
to generate power. I have this long piece of superconducting cable to
use as the orbiting armature...

    It's been too long since I took electricity in High School,
and I'm rather foggy on the details, so there are probably showstoppers
for that idea, too (and possibly gooched terminology).

                            James Nicoll

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

Date: 10 Jan 91 00:08:48 GMT
From: zephyr.ens.tek.com!tektronix!sequent!crg5![e-mail]  (Nick Szabo)
Subject: Re: shuttle was answer

In article <[e-mail]> [e-mail] writes:
>Henry Spencer quips:
>
>-if the space shuttle was the answer, what was the question-
>
>How about:
>
>what is a bargain compared to many of the other Gov't "spending"
>programs including, but not limited to:
[examples to show NASA is not the only govnt bureaucracy wasting money]

Ah, the good old "they're wasting money so we can waste money too!"
argument.  In private industry, a sure way to go bankrupt. But the
perfect argument for a government bureaucracy seeking to feed itself.
I say it three times I say it three times I say it three times:
LEARN TO BE EFFICIENT.  Pioneers use what they have.  Whiners stay
home.  'nuff said.


--
Nick Szabo            [e-mail]
Embrace Change...  Keep the Values...  Hold Dear the Laughter...

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

Date:    Wed, 9 Jan 91 01:38:36 MST
From: [e-mail] (Cary Oler)
Subject: SPECIAL SOLAR TERRESTRIAL BULLETIN AND STRATWARM ALERT UPDATE
X-St-Vmsmail-To: ST%"[e-mail]"

                        /\/\/\/\/\/\/\/\/\/\/\/\/\

                    SPECIAL SOLAR TERRESTRIAL BULLETIN

                            Information Update
                             08 January, 1991

                        /\/\/\/\/\/\/\/\/\/\/\/\/\


SOLAR CONDITIONS AS OF 08 JANUARY, 1991.

     As was anticipated, Region 6442 (S11W59) began producing M-class flares
on 08 January.  It has produced three M-class flares over the past 24 hours.
The first flare occurred at 04:34 UT and lasted 61 minutes.  It achieved a
class M1.8/1N intensity and was associated with a 640 s.f.u. (solar flux unit)
radio burst at 10 cm wavelengths.  The second flare occurred at 06:56 UT and
lasted 20 minutes.  It was rated as a class M1.1/SF flare and was not
associated with any significant radio bursts.  The third flare occurred at
11:27 UT and lasted 32 minutes.  It was rated as a class M1.2/1N flare and was
associated with a 1,100 s.f.u. radio burst at 245 MHz.  The locations of these
flares were at S11W48, S12W50 and S13W51 respectively.  Region 6442 has begun
to slow in growth and is expected to enter a decline phase after it passes
beyond the west limb on 10/11 January.  However, it is expected to continue to
produce M-class flares throughout the remainder of it's transit over the west
limb.

     Of perhaps equal importance were the events which have transpired over the
eastern solar limb.  Region 6444 (N14E65) has rotated into better view now and
has revealed numerous additional trailing spots.  It is not yet clear whether
the trailing spots are associated with Region 6444 or with old Region 6412
(which produced two powerful X-class flares just prior to it's passage beyond
the west limb two weeks ago).  This determination will be made clear over the
next 24 hours as the eastern regions rotate into better view.

     An eruptive prominence occurred on 08 January from behind the east limb.
This event was associated with a long-duration class C7.5 x-ray burst, which
peaked in intensity at 18:48 UT.  The event lasted 72 minutes and managed to
push the background X-ray flux for 08 January to a class C2.3 level (well
above the C1.5 background levels measured on 07 January).  In addition, this
eruptive prominence was associated with a strong Type II radio sweep.

     It will be interesting to observe the emergence of these eastern active
centers over the next several days.  The threat for M-class flaring is
expected to remain high for at least the next 48 hours, and likely throughout
the next week.  The current sunspot number is 145, but is expected to climb
quite dramatically over the next 48 hours, before levelling off.  The
disappearance of Region 6442 beyond the west limb will produce a drop in the
sunspot numbers, but Regions 6444 and the active area's just beyond the eastern
limb are expected to keep sunspot numbers elevated.


STRATOSPHERIC WARMING ALERT UPDATE - 08 JANUARY, 1991.

     The stratospheric warming alert is being continued.  This alert will
likely remain in effect for at least the next 7 to 10 days.  The stratospheric
warming has become very intense with a center over Greenland.  The affected
area's are continuing to expand and spread northeastwards.

     For those who are unfamiliar with stratospheric warming alerts, here is a
brief explanation of these events.  A stratospheric warming alert is issued
whenever abnormally high temperatures are observed in the earth's stratosphere,
which is the atmospheric transition zone between the trophosphere (the lower
atmosphere we live in) and the ionosphere.  Large area's of intense
stratospheric warming can cause atmospheric expansion sufficient to increase
drag on satellites.  There is also some evidence that intense stratospheric
warming events can cause changes in atmospheric circulation and weather
patterns.  This area is still being researched however, and is far from
conclusive.

     Intense solar activity can cause atmospheric expansion.  However,
stratospheric warming events are more often associated with natural processes
occurring in the earth's atmosphere.  Stratospheric warming tends to occur most
often during the winter months and can appear quite suddenly and intensify
quite rapidly.  Abnormally high temperatures in the stratosphere cause changes
in stratospheric circulation patterns and other characteristic changes.  They
pose no threat to man, but do warrant attention.

     Stratospheric warmings are relatively rare.  The last stratospheric
warming alert was issued on 08 February, 1990 and lasted for over two weeks.
This event is expected to be of a similar duration.  We are in day 6 of the
"Stratwarm Alerts" as of 08 January, 1991.


**  End of Bulletin  **

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

Date: 9 Jan 91 16:54:12 GMT
From: swrinde!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: LOX/LH2 in Shuttle Payload Bay

In article <[e-mail]> [e-mail] (Christopher Neufeld) writes:
>>Why not mount the Centaur upside down? ...
>  ... pictures of objects leaving the cargo bay
>always show the rocket nozzle of the Centaur or IUS pointing at the
>floor of the payload bay, which would make the rocket horizontal in the
>launch stack configuration. Is there a gimbal which swings the whole
>thing to vertical...

For large payloads, the sort that go up on an IUS (or would have gone up
on a Centaur), the nozzles point at the rear of the bay during launch.
The IUS is held in a mounting ring which pivots to point the assembly out
of the payload bay for separation.  Centaur was similar.

Mounting such an assembly upside down wouldn't entirely solve the problem,
and would add some new ones.  The payloads aren't built to carry external
loads.  What you really want is a more complex cradle system that would
support payload and upper stage independently.
--
If the Space Shuttle was the answer,   | Henry Spencer at U of Toronto Zoology
what was the question?                 |  [e-mail]   utzoo!henry

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

Date: Wed, 9 Jan 91 22:36:22 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Umbra (eclipse shadow) satellite photo


>From: swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
>Subject: Re: Could weather sat snap umbra 11-7-91?

>In article <[e-mail]> [e-mail] (David Cortesi) writes:
>>There are these fine weather satellites looking down on the west
>>coast and pacific.  Would it be possible for one of them to take
>>pictures of the umbra, a 300 kilometer oval of shadow, as it
>>sweeps over Baja or Mexico on that day?

>I suspect that the answer is no.  The trouble is that the Clarke-orbit
>metsats typically spend about half an hour doing a raster scan of the
>Earth for each image.  They're not built for stop-motion photography,
>even motion as slow as this.

>"The average pointer, statistically,    |Henry Spencer at U of Toronto Zoology
>points somewhere in X." -Hugh Redelmeier| [e-mail]   utzoo!henry

I recently saw a published satellite photograph of an umbra, with an
explanation that ordinary weather satellites couldn't do it. Unfortunately,
I can't remember the name of the satellite or where I saw the picture. :-(
      John Roberts
      [e-mail]

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

Date: 8 Jan 91 14:56:39 GMT
From: mcsun!ukc!tcdcs!swift.cs.tcd.ie!ccvax.ucd.ie![e-mail]
Subject: Re: space news from Dec 10 AW&ST (TIRE DAMAGE)

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> Langley engineers pleased:  Atlantis's tires showed neither a spin-up gouge
> nor excessive wear after the KSC landing Nov 20.  The changes to the runway
> surface, meant specifically to reduce tire damage, appear to have been
> successful.

I thought about this for a while (tire damage on landing) the last time it was
mentioned, but then forgot about it - the thing that sprang to mind at the time
was:
  why not spin-up the tires (whoops - american spelling) BEFORE landing - maybe
by using ducts attached to the wheels to harness the 230mph.ish winds (230mph I
think ?)



Neil Conway
Physics Dept.
Univ. Coll. Dublin
Ireland
[e-mail]

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

Date: 9 Jan 91 19:53:24 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Humankind's Second Off-world Colony

In article <[e-mail]> [e-mail] (Jon Monsarrat x6227) writes:
>Where should Man's first colony after a moon colony be?
> OUR GUESS: Ganymede because of its water supply and proximity to Jupiter
>  which is a good source of gases possibly used in fusion...

Ganymede has the unfortunate problem of being in the outer fringes of
Jupiter's Van Allen belts, as I recall.  Callisto would be a better bet.

>What would the motivations for having a colony be?

Historically, colonies are motivated either by money or by the desire to
escape oppression.  The obvious economic motive for a colony on a Jovian
moon is exploitation of Jupiter's resources.  In particular, given cheap
transport, the smaller Jovian moons might be the most convenient sources
of volatile materials -- notably water -- for space activities elsewhere
in the solar system.  (Carbonaceous-chondrite asteroids are an alternative,
but if transport is cheap enough, the problems of extracting volatiles from
them might exceed their advantages of being closer in.)  This requires
sufficiently major space activity for there to be a lot of customers.
Smaller amounts would be brought back by self-contained expeditions; only
when these started becoming common would it be worth starting a base; only
when supplying the base and rotating personnel started to be a nuisance
would it be worth starting a colony.

At an earlier stage of space activity, a Jovian moon might be a good place
to start an escape-from-oppression colony.  Such folks generally want
isolation, the more the better, or else they'd just find somebody here
on Earth willing to take them in.  They wouldn't move in next to a thriving
mining operation.  However, they might find such an operation growing up
next to them after a while.  Interesting plot possibilities there.

Most other possible motives for a colony, e.g. dangerous research, are
better satisfied by inner-system asteroids.  One major nuisance of a
colony on a planetary body is that solar energy is much less available,
because it's night half the time.  The Jovian moons suffer in this regard
because they are (as I recall) tidally locked to Jupiter, so their day/night
cycle matches their orbital cycle, and is inconveniently long.

>What would be the basic physics of the colony?

A major aspect of this is, where does the power come from?  Choices boil
down to solar or nuclear, unless you can find geothermal activity.  (There
is lots of that on Io, but it's not good real estate.  Not likely to be
much on the outer moons.)

>How dependent would such a colony be on Earth?

This is slightly dependent on the colonists' motives; an isolationist colony
will try to be independent in ways that a commercial colony would not bother
with.  Trace elements will probably have to come from Earth, ditto complex
biochemicals and advanced semiconductors.  An isolationist colony might try
to get along without the last two, but would probably need very occasional
trade for trace elements -- recycling systems always lose some, and even
on Earth you can work long and hard to find ores of the rarer ones.  A
commercial colony, especially one based on cheap transport, would probably
not try to be independent except in basic life support and bulk materials.

>How might a Ganymede-Earth communication system work?
>How often and when are there Earth-sun-Jupiter eclipses? How long are they?

Earth is behind the Sun for a week or two about once a year.  A Jovian moon
is behind Jupiter for a small slice of each orbit.  It might not be worth
doing anything about either one.  An isolationist colony, in any case, might
want only occasional communication with Earth.  A commercial colony would
possibly want a comsat to avoid having Jupiter get in the way of local
communications, and given that would probably use it to avoid Jupiter
eclipses of Earth communication as well.

>What are the long term effects of living in Ganymede's 1/7th gravity?

Totally unknown.  One very interesting possibility is shorter (!) lifespan;
if I recall correctly, mice live longer in centrifuges than at one gee.
(Yes, this is very counterintuitive, but lifespan issues abound with such
surprises:  slight under-nutrition also lengthens lifespan.)

>If low gravity was inhospitable to man, what would be the solution?

Build a space colony in orbit around Ganymede or Jupiter, or tied up to
one of the really small moons (for easier access to resources).

>Ganymede has a low pressure atmosphere, but what's it composition?
> OUR GUESS: 5 millibars water vapor??

It will be vacuum for almost all practical purposes.
--
If the Space Shuttle was the answer,   | Henry Spencer at U of Toronto Zoology
what was the question?                 |  [e-mail]   utzoo!henry

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

Date: Wed, 9 Jan 91 12:16:32 PST
From: [e-mail] (Troy T. Pummill)
Subject: Salyut orbital elements


Does anyone plan to increase the frequency of orbital element update
releases as Salyut gets closer "touch down" :-)

trop (Troy)

-------------------------------------------------------------------------------
|  Troy T. Pummill         |  [e-mail]                              |
|  Sr. Technical Instructor      |  ...uunet!lanslide.hls.com!trop            |
|  Hughes LAN Systems            |                                            |
|  [phone]                |  1225 Charleston Rd., Silicon Gulch        |
|  Mountain View, CA  94043     |  The preceding drivel is entirely my own!  |
------------------------------------ ------------------------------------------

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

Date: 10 Jan 91 02:56:59 GMT
From: att!emory!athena.cs.uga.edu![e-mail]  (Roggie Boone)
Subject: HSTMAP for IBM PC

I few days ago I read about a program called HSTMAP, apparently a program
that allows one to follow the Hubble Space Telescope via a graphical
representation of its orbit on a computer screen.   This program was for
the Macintosh computer.  Is there am IBM PC version of this program
available?

Please email replies to [e-mail]

Thank you.

Roggie Boone
University of Georgia

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

End of SPACE Digest V13 #035
*******************