Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_382.TXT

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Subject: SPACE Digest V8 #382

SPACE Digest                                      Volume 8 : Issue 382

Today's Topics:
          A new approach to space Digesting
               Re: Cosmos 1900?
               Re: Cosmos 1900?
               Re: Cosmos 1900?
               Re: Cosmos 1900?
               Re: Cosmos 1900?
           US Elint--useless orbit.  Info?
  Dinosaur extinction compared to others (was: are we terraforming?)
         Re: Are we ready for terraforming???
               Orbit tracking software?
           The Cretaceous extinction event
----------------------------------------------------------------------

Date: Thu, 29 Sep 88 10:27:44 -0400 (EDT)
From: Ted Anderson <[e-mail]>
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Subject: A new approach to space Digesting

This note is primarily of interest to readers of the Space Digest.  For those
who don't know, that is a periodic compilation of messages sent to a list of
recipients throughout the internet.  All the messages in the Digest also
appear on the Usenet bulletin board sci.space, but it is designed so that
people without access to Usenet can receive those messages by direct mail.

The Space Digest has gotten out of hand.  The message queue has reached
three-quarters of a megabyte even though digests have been going out ten times
a week.  Between 6AM and 4PM yesterday 57 Kilobytes of new mail arrived: two
or three digests worth.  Many people are surely getting tired of scanning all
this traffic to find messages of interest.  For the last few months I've been
managing the mailing list, bicoastally: part of the process happens on a
computer in California and part uses the facilities where I am physically
located in Pennsylvania.  This changed last night so everything is now running
on the Andrew system here at CMU.  But the inevitable interruptions caused by
this transition are only going to make the backlog worse.

Starting very soon, I'm going to divide the digest into two parts.  One of
these parts is going to be completely upward compatible with the current
digest.  It will be mailed out often enough to keep the backlog at about a
week and hopefully will be a bit more timely as a consequence.

The second part, which I'm going to tentatively call a magazine, is intended
to be more moderated.  It will be more like a newspaper than a letters to the
editor column.  There will be much less of the followup and discussion that
characterize the Digest.  At the moment this is all vaporware, but I have a
plan.

The plan calls for a collection of topical editors to gather material from
their own sources or by selecting messages from the unedited network traffic.
 They will submit their material to one of two addresses depending on whether
it is "new" or culled from the network.  The magazine will be assembled from
these submissions and mailed out to a list of subscribers.  In addition, the
"new" material will be forwarded to the digests so that the magazine will
contain a proper subset of the material in the digest.

I imagine the editors' domains to be divided by subject matter so that they
can work more or less independently without worrying about duplication.  I
expect editors to be people with access to information about a topic or
special interest or expertise in a topic.  There are people who already submit
material to the digest who fit this description, but there are hopefully
others as well.  Several topics that come to mind are SETI, NASA, the Soviet
program, commercial activities, the Station and Shuttle, Mars, the Moon, and
certainly others.  The list of working topics will depend on the editors
themselves.

I am looking volunteers to be editors.  If you are interested in this
experimental effort send me a note giving me some idea of your interests, any
special expertise you have, what kind of network access you have, and anything
else you think might be relevant.

In addition if you'd like your subscription to be moved from the digest to the
magazine or just want to be added to the magazine let me know.  Keep in mind,
however, that until I get some editors the magazine will be very thin.

    Ad astra per aspera,
    Ted Anderson

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

Date: Thu, 22 Sep 88 11:22:34 PST
From: Peter Scott <[e-mail]>
Subject: Re: Cosmos 1900?
X-Vms-Mail-To: EXOS%"[e-mail]"

>mcvax!enea!kth!draken!chalmers!tekn01.chalmers.se![e-mail]
>   (Mikael Lerner) writes:

>    Sometimes there have been 'horror'-stories in the Swedish news-
>    papers about the Soviet Cosmos 1900-satellite, with which the
>    Russians have lost radio contact, which means that they can't
>    separate the nuclear reactor that powered the satellite.

Not manually, but there is an automatic system designed to separate
the nuclear reactor when it detects a temperature rise (caused by
atmospheric heating), which is still intact.  They expect that this will
be triggered around 120km and separation will take place at 100km.
Separation increases the chance of the reactor burning up, although I
for one can't see the benefit of having radioactive dust scattered
through the stratosphere or maybe even troposphere compared with having it
all land within a relatively small area.

Peter Scott ([e-mail])

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

Date: 23 Sep 88 15:43:36 GMT
From: att!cbnews![e-mail]  (William B. Thacker)
Subject: Re: Cosmos 1900?

In article <[e-mail]> [e-mail] (Peter Scott) writes:
>Separation increases the chance of the reactor burning up, although I
>for one can't see the benefit of having radioactive dust scattered
>through the stratosphere or maybe even troposphere compared with having it
>all land within a relatively small area.

I would suppose that, if the reactor burns up, the radioactive dust is
scattered so widely as to be indistinguishable from background. If,
however, it lands in a small area, it could pose a health hazard (suppose,
for example, it lands in a town reservoir).

Plus, landing in one chunk, it could hit someone in the head, which could
also present a bit of a health hazard... 8-)



------------------------------ valuable coupon -------------------------------
Bill Thacker                        cbosgd!cbema!wbt
    "C" combines the power of assembly language with the
     flexibility of assembly language.
Disclaimer: Farg 'em if they can't take a joke !
------------------------------- clip and save --------------------------------

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

Date: 23 Sep 88 17:03:28 GMT
From: attcan!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Cosmos 1900?

In article <[e-mail]> [e-mail] (Peter Scott) writes:
>I for one can't see the benefit of having radioactive dust scattered
>through the stratosphere or maybe even troposphere compared with having it
>all land within a relatively small area.

We've coped with radioactive dust in the stratosphere in the past, since
the US and the USSR put up quite a lot of it in the 50s, and the Chinese
and the French are still doing so on a smaller scale.  There isn't enough
in one of those little satellite reactors to be a dire problem that way.
Having it come down in one small area is great if the area happens to be
in the Sahara, but not so great if it's in Manhattan.
--
NASA is into artificial        |     Henry Spencer at U of Toronto Zoology
stupidity.  - Jerry Pournelle  | uunet!attcan!utzoo!henry [e-mail]

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

Mon, 26 Sep 88 14:31:34 EDT
Date: 26 Sep 88 16:01:46 GMT
From: beta![e-mail]  (William Johnson)
Subject: Re: Cosmos 1900?

In article <[e-mail]>, [e-mail] (Peter Scott) writes:

[Re: the "feature" of Cosmos 1900 that (they hope ...) will cause its
core to re-enter separately and burn up in the upper atmosphere]

> Separation increases the chance of the reactor burning up, although I
> for one can't see the benefit of having radioactive dust scattered
> through the stratosphere or maybe even troposphere compared with having it
> all land within a relatively small area.

The advantage is this: much (in the first few hours after re-entry, an
extremely large fraction) of the radioactivity associated with the core
consists of fission products.  These characteristically have short half
lives, of the order of hours or days, although there are a few that do
last longer.  If the core burns up in the upper atmosphere, the
short-lived isotopes decay away before they make it to the ground (it
takes quite a while for stuff to cross the tropopause) and therefore
pose no hazard at all.  If a chunk of core made it to the surface in one
piece, there would be some potential for exposing the public to
radiation from the short-lived isotopes in the chunk before they
decayed.

Your concern would be well founded if the core didn't disperse until it
had penetrated the tropopause (i.e., made it to the troposphere),
because stuff in the troposphere gets washed out much more quickly than
stuff in the upper layers of the atmosphere.  However, if the core is
going to burn up at all, it is most likely to do so farther up.

Incidentally, this seems like a good time to plug for creation of a
group like sci.meteorology or sci.weather.  I can speak with
considerable expertise on the physics issues (like what isotopes a
reactor core contains), but it might be interesting for someone more
knowledgeable on meteorology to provide figures on washout times of
material entrained in the stratosphere and/or troposphere.  Anybody
that's listening got those?

"One thing they don't tell you about doing    | Bill Johnson
experimental physics is that sometimes you    | Los Alamos Nat'l Laboratory
must work under adverse conditions ... like    | Los Alamos, NM, USA, Earth
a state of sheer terror." (W. K. Hartmann)    | ([e-mail])

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

Date: 26 Sep 88 22:29:29 GMT
From: beta![e-mail]  (William Johnson)
Subject: Re: Cosmos 1900?

In article <[e-mail]>, I (Bill Johnson @ somewhere) wrote:
[Re: the "feature" of Cosmos 1900 that (they hope ...) will cause its
core to re-enter separately and burn up in the upper atmosphere, and someone's
question of why one would want this to happen]
>
> The advantage is this: much (in the first few hours after re-entry, an
                                                            ^^^^^^^^
    (Excuse me; I should have said "reactor shutdown".)

> extremely large fraction) of the radioactivity associated with the core
> consists of fission products.  These characteristically have short half
> lives, of the order of hours or days, although there are a few that do
> last longer.  If the core burns up in the upper atmosphere, the
> short-lived isotopes decay away before they make it to the ground (it
> takes quite a while for stuff to cross the tropopause) and therefore
> pose no hazard at all. [...]

Paul Dietz correctly pointed out via e-mail [did you get my reply, Paul?] that
the advantage here would be largest only if the reactor was operating all the
way up until re-entry.  However, even if it was shut down some days or weeks
ago, the same principles apply; things can stay entrained in the upper
atmosphere for months if not years, and one year of entrainment is worth
a factor of FIFTY in radioactivity reaching the surface.  Inquiring minds might
look at a paper in the journal _Health Physics_ (Tracy et al., H. Phys. v. 47,
p.225, 1984) that talks comprehensibly about the health impact from Cosmos 954,
another Russian reactor satellite that came down ten years ago.

--
"One thing they don't tell you about doing    | Bill Johnson
experimental physics is that sometimes you    | Los Alamos Nat'l Laboratory
must work under adverse conditions ... like    | Los Alamos, NM, USA, Earth
a state of sheer terror." (W. K. Hartmann)    | ([e-mail])

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

Date: 6 Sep 88 19:55:42 GMT
From: pikes!udenva!isis!scicom![e-mail]  (Bruce Watson)
Subject: US Elint--useless orbit.  Info?


On 1988 Sep 2 in the EDT am, an early warning elint was launched from
the Cape on a Titan 34D toward a geosynchronous orbit.  The final burn
to circularize at 22,300 miles failed.  The resulting orbit of approx 100
by 22,300 miles renders the mission useless.

If I had the time of launch and the current inclination I could come up
with approximate elemeents and times and angles for observation.

Any info?

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

Date: 13 Sep 88 22:15:49 GMT
From: [e-mail]  (Jim Giles)
Subject: Dinosaur extinction compared to others (was: are we terraforming?)

From article <[e-mail]>, by [e-mail] (Mike Trout):
> [...]
> Why did so many non-dinosaur reptiles survive?  Snakes, turtles, lizards,
> crocodilians, and such appear to have suffered no such losses at the time.
> And it doesn't have anything to do with size, either.  Although most of the
> "big" dinosaurs get all the attention, most dinosaurs actually were not all
> that large--many were no larger than modern-day lizards, and their average size
> seems to be little different from today's crocodilians.  Yet not one single
> dinosaur, regardless of size, survived whatever it was.  It's difficult to
> come up with a plausible scenario in which all dinosaurs die and most lizards
> live, even though biologically they are extremely similar.  A baffling
> mystery, to say the least.

Too much attention is paid to dinosurs.  The iridium even marks a significant
mass extinction event.  Over half the families of marine mollusks, flowering
plants, echinoderms, etc. were killed off (for half the _families_ to
disappear, more than 90% of the species must be killed off).

The question is not: why did the dinosaurs die off?  The question is: how
did all these others survive.  Actually, they probably didn't.  Mammals
are probably all derived from only one or two dinosaur contemporaries.
The same goes for birds.  Each family of living reptiles and amphibians
probably owes its existance to only one or two survivor species.  In fact,
the asteroid theory is quite adequate to explain all the extinctions -
the robustness of life is necessary to explain the survivors.

J. Giles

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

Date: 12 Sep 88 22:09:26 GMT
From: brspyr1![e-mail]  (Mike Trout)
Subject: Re: Are we ready for terraforming???

> > >(Jim Giles) writes:

> > Well, it does appear that a single asteroid hitting Australia wiped
> > out the dinosaurs.

It's my understanding that this theory is highly questionable at best.  While
there is substantial circumstantial evidence to support it (layers of iridium,
apperance of chronological time-scale catastrophe, mathematical climatological
models, etc.), there is one major problem...

Why did so many non-dinosaur reptiles survive?  Snakes, turtles, lizards,
crocodilians, and such appear to have suffered no such losses at the time.
And it doesn't have anything to do with size, either.  Although most of the
"big" dinosaurs get all the attention, most dinosaurs actually were not all
that large--many were no larger than modern-day lizards, and their average size
seems to be little different from today's crocodilians.  Yet not one single
dinosaur, regardless of size, survived whatever it was.  It's difficult to
come up with a plausible scenario in which all dinosaurs die and most lizards
live, even though biologically they are extremely similar.  A baffling
mystery, to say the least.

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

Date: 13 Sep 88 18:04:41 GMT
From: att!mtuxo!mtuxj![e-mail]  (Thomas E. Kenny)
Subject: Orbit tracking software?

What software is used for tracking the man-made satilites? Does the
software run on MSDOS or UNIX? Does anybody have source? Are graphics
displays of the orbit included? Any information would be appreciated,
thanks in advance!

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

Date: 13 Sep 88 06:42:50 GMT
From: cca![e-mail]  (Richard Harter)
Subject: The Cretaceous extinction event

In article <[e-mail]> [e-mail] (Mike Trout) writes:
>> > >(Jim Giles) writes:

>> > Well, it does appear that a single asteroid hitting Australia wiped
>> > out the dinosaurs.

    Location not known, several candidates.


>It's my understanding that this theory is highly questionable at best.  While
>there is substantial circumstantial evidence to support it (layers of iridium,
>apperance of chronological time-scale catastrophe, mathematical climatological
>models, etc.), there is one major problem...

    Debatable, and hotly debated, but not highly questionable.  The
competing theories are (a) multiple cometary strikes over an extended period
of time (Oort cloud perturbation), (b) extended vulcanism, and (c) ecological
collapse due to changes in geography.  Theory (a) is an alternate catastrophe
theory, theory (c) postulates a much longer time frame for the extinction,
and (b) is somewhat of a hybrid as far as time is concerned.

>Why did so many non-dinosaur reptiles survive?  Snakes, turtles, lizards,
>crocodilians, and such appear to have suffered no such losses at the time.
>And it doesn't have anything to do with size, either.  Although most of the
>"big" dinosaurs get all the attention, most dinosaurs actually were not all
>that large-many were no larger than modern-day lizards, and their average size
>seems to be little different from today's crocodilians.  Yet not one single
>dinosaur, regardless of size, survived whatever it was.  It's difficult to
>come up with a plausible scenario in which all dinosaurs die and most lizards
>live, even though biologically they are extremely similar.  A baffling
>mystery, to say the least.

    Not all that difficult.  One note -- the minimum size for dinosaurs
(adult) was about the size of a large chicken.  It is a matter of debate
whether dinosaurs were "warm blooded" in the sense of having a fully regulated
body temperature; however this is no real doubt that they had much higher
metabolisms (and corresponding continuing high food requirements) than
reptiles. As such they were much more sensitive than reptiles to a
catastrophic ecological collapse with a wide destruction of the food chain.
The Cretaceous extinction was very broad -- it hit all the large animals
(including the large reptiles), large numbers of sea life forms, and a
fair bit of the plant kingdom.




--

In the fields of Hell where the grass grows high
Are the graves of dreams allowed to die.
    Richard Harter, SMDS  Inc.

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

End of SPACE Digest V8 #382
*******************