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Subject: SPACE Digest V10 #275

SPACE Digest                                     Volume 10 : Issue 275

Today's Topics:
          Asteroid strikes and warning times
Access to Playalinda Beach to improve with Pad A operations (Forwarded)
              Galileo Update (Forwarded)
        Re: Asteroid strikes and warning times
         Re: Planetary Society - net address
            Re: Moon Colonies / Ant Tanks?
           Software for planetary positions wanted
              Shuttle Launch Orientation
       Planetary Society - summary of responses to net address
----------------------------------------------------------------------

Date: 22 Nov 89 04:15:38 GMT
From: att!cbnews![e-mail]  (Patrick A. Hillmeyer)
Subject: Asteroid strikes and warning times


From: "Patrick A. Hillmeyer" <[e-mail]>


  I just read an article in the newspaper today about geologists who believe
they have located the crater from the asteroid strike that wiped out the
dinosaurs.  As I was reading this I got to wondering....

    If an asteroid was about to strike the Earth tommorrow, next year, or even
five minutes from now, what amount of warning would we get?  Would NASA, NORAD,
SAC, or the European or Soviet equivalents be able to provide any practical
degree of warning?  If they could give a warning would it be early enough to
do anything?  I'm not talking about enough warning to evacuate people (I don't
think we have anywhere near that amout of warning capability and if we did we'd
also be able to stop the strike).  I'm wondering if there would be enough time
to get out the word that this is a natural disaster and not a first strike.

  After all, if there was very little warning or none at all, the first
indication would detection of a fast moving, inbound object toward the target
area and then reports of massive destruction.  What would keep the unfortunate
target country from thinking it was under attack (especially if tensions were
already high due to other reasons)?  Are there any kind of US/Soviet or
international/UN agreements on this type of thing? Does anybody know what the
military has in the way of detection capability for objects coming in from
space?  Are there any contingency plans for contacting the Soviets immediately
and assuring them that it wasn't a US attack (if it should hit the USSR)?  If
it struck the US is there any way for us to immediately know that it wasn't
a Soviet surprise attack?

  I just don't like the idea that a natural disaster could trigger a nuclear
exchange.  I'd like to think that there are backup plans and failsafes to
prevent this from happening.

                                             -Pat


   P.S. please use sci.military for militarily related followups and sci.space
        for non-militarily related followups - Thank you.
[mod.note:  Followup-to: set to sci.space.  Correct as needed.  - Bill ]

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

     09 NOV 1989   The Wall comes down
     10 NOV 1989   The 214th birthday of the United States Marine Corps

disclaimer : I don't speak for the Navy, I don't speak for the Marine Corps,
             and I don't speak for the U of MN.

  Patrick A. Hillmeyer  ([e-mail])

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

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

Date: 22 Nov 89 21:36:23 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Access to Playalinda Beach to improve with Pad A operations (Forwarded)

[Quick, get out your beach towels! -PEY]

  Bruce Buckingham                                  Nov. 22, 1989

  Release No. 121-89

  ACCESS TO PLAYALINDA BEACH TO IMPROVE WITH PAD A OPERATIONS


       Playalinda Beach will reopen the day after the STS-33 launch
  and remain open until three days before the STS-32 launch in
  December.

       The beach will be closed to the public for shorter periods
  of time when Space Shuttles are being prepared for launch from
  Pad 39-A at Kennedy Space Center.

       Since 1986 Space Shuttles have been launched exclusively
  from Pad-B. The beach access, which lies within a three-mile
  security zone surrounding the pad, is restricted beginning the
  evening before a Shuttle vehicle is transferred to the pad and
  continues until the day following launch, usually a period of
  several weeks or more.

       NASA plans to resume Space Shuttle launches from Pad-A in
  December 1989. Because Playalinda Beach falls outside Pad-A's
  three-mile security zone, beach access will be restricted to a
  period of only three days before launch until the day after.

       The lengthened beach access applies only to launches from
  Pad-A. Pad-B restrictions will continue as before.

       In the likelihood of simultaneous Shuttle launch
  preparations at Pads A and B, the restrictions imposed for Pad-B
  will prevail.

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

Date: 22 Nov 89 22:46:21 GMT
From: cs.utexas.edu!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update (Forwarded)


                      GALILEO WEEKLY STATUS
                        November 22, 1989


     As of Wednesday, November 22, the Galileo spacecraft is 6.97
million miles from Earth (round-trip light time 75 seconds or 1
1/4 minutes); it has travelled 50 million of the 185 million
miles around the Sun to its Venus gravity-assist rendezvous in
February 1990.  The first trajectory correction maneuver (carried
out November 9-11) was very successful; trajectory analysis
indicates a slight over-performance. TCM-2 (planned for December
22) is expected to be less than 1 meter per second; TCM-1 was
almost 16 m/sec, mostly toward the sun and mostly to remove an
intentional bias rather than launch errors.

     The maneuver was conducted in the dual-spin mode, with the
4100-lb main section of the spacecraft rotating at about 3 rpm
while the 700-pound lower section and the 750-pound atmospheric
probe are counter-rotated to stay sta-tionary.  In this mode,
Galileo's camera and other remote sensors can be precisely aimed
during a planetary flyby.  The spacecraft remained in this mode,
so that turns to keep it Sun-pointed can be done automatically.

     Spacecraft communication equipment was switched on November
15 from Low Gain Antenna 1 (looking toward the Sun)
to LGA 2 (looking the opposite way) to keep up with the
changing Sun-spacecraft-Earth geometry. On the 19th, the
data rate was reduced from 1200 to 40 bits per second to free
the DSN 70-meter antenna briefly for other projects. The rate
goes back up today.

     The spin rate is currently just over 3 rpm, and the
spin axis is being moved nearly every day to keep the
spacecraft Sun-pointed within a degree.  The RTGs continue to
deliver about 570 watts of electric power. All temperatures
and propulsion system pressures are within acceptable ranges,
although the dust detector instrument is significantly
cooler than expected.

     The magnetometer and heavy ion counter are the only
instruments powered at present.  A four-day science checkout
is scheduled for December 27-30 in preparation for the Venus
science encounter in February.



 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

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

Date: 23 Nov 89 18:02:28 GMT
From: cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!ists!yunexus!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Asteroid strikes and warning times

In article <[e-mail]> [e-mail] (Patrick A. Hillmeyer) writes:
>    If an asteroid was about to strike the Earth tommorrow, next year, or even
>five minutes from now, what amount of warning would we get?

Possibly a few days if the astronomers happened to see it.  More probably,
essentially zero.

>Would NASA, NORAD,
>SAC, or the European or Soviet equivalents be able to provide any practical
>degree of warning?

Not unless the asteroid helpfully came in on a fairly northerly trajectory,
and even then warning would be measured in minutes, not days.  Against
small distant targets with no unusual reflection characteristics, radar
effectiveness is an inverse *fourth power* function of distance -- the
inverse-square law gets you once each way -- and so the effective detection
range is short.  The sort of interplanetary radar work that the radar
astronomers do is very specialized and depends very much on the target
being in a known place.

In the Southern Hemisphere, there are no big radars at all.

>If they could give a warning would it be early enough to
>do anything?  ...  I'm wondering if there would be enough time
>to get out the word that this is a natural disaster and not a first strike.

If it came in on the right sort of trajectory and was recognized for what it
was, maybe.  I wouldn't put a large bet on it myself.
--
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry [e-mail]

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

Date: 23 Nov 89 18:10:48 GMT
From: mailrus!jarvis.csri.toronto.edu!ists!yunexus!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Planetary Society - net address

In article <[e-mail]> [e-mail] (Joel Haynes) writes:
>... In their field they do act, as an
>example they have been actively promoting the manned exploration of
>Mars and have even been pushing for a joint US-Soviet mission and
>sponsored events to bring this about...

In certain limited areas of their field they do act.  Last I heard, their
position on the Moon was "six landings is enough", notwithstanding the
long we-need-more-data wishlists of lunar scientists.

Some people (e.g. me) smell political motives in their determination that
a Mars mission *has* to be international.  I.e., one might suspect that
promotion of international cooperation is the big agenda item, and the
possibility of getting more science return cheaper (e.g. from the Moon)
be damned.
--
That's not a joke, that's      |     Henry Spencer at U of Toronto Zoology
NASA.  -Nick Szabo             | uunet!attcan!utzoo!henry [e-mail]

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

Date: 22 Nov 89 07:45:17 GMT
From: mentor.cc.purdue.edu![e-mail]  (Mark Gellis)
Subject: Re: Moon Colonies / Ant Tanks?

All right, you engineer types, here are a few questions...

O'neill claims that you can build a space colony (cylinder-type) with a
radius of 3.2 km. and a length of 32 km. and a surface density of 7.8 tons/
meter if you allow 150,000 psi of tensile strength in your building
material (the reference is his article on space colonies in--I think--
the September 1974 issue of PHYSICS TODAY)--and spin it to get about
one Earth gravity on the interior surface.

I would be grateful if anyone could answer a few questions about this
design...

First, I know that you can build much larger structures if you have
stronger materials.  (I understand graphite "whiskers" have a tensile
strength of 3 million psi--please let me know if I'm wrong here, I'm
using Forward's book FUTURE MAGIC (he means technology, so forgive
the goofy title) as a reference.)  But this means you have to have
carbon as an initial material.  How common is carbon in the solar
system (not counting hard to reach places like the core of the sun)?
Could it be, say, extracted from the ice/junk surfaces of the moons
of the gas giants?

Second, for anyone who knows anything about fusion reactions, also
related to carbon.  If you have controlled fusion power (which we
should have sometime in the next hundred years), can you simply make
carbon from helium?  (As I understand, fusion reactions in the core
of a star can do this...if we had controlled fusion, could we simply
make all the carbon--and other elements--we want?  I've heard yes
and no on this question from various sources; I would be interested
in hearing various views on this one).

Third, besides the carbon whiskers, does anyone have other suggestions
about what kind of materials could be used for large space habitats
(titanium has a tensile strength of 40,000-200,000 depending on alloys,
and I beleive kevlar has one of 400,000)?  What other composite materials
could be used?  What kind of problems would be involved?

Fourth, O'neill has his space habitat as a 6.4 km x 32 km. cylinder.
Is there any reason why a cylinder in space could not be made longer?
Could you build a 6.4 km. x 320 km. cylinder, for example (which would
give you ten times the living space at, one might think, no additional
structural problems, aside from just fitting the big pieces together)?
Or would stress increase with the length as well as the diameter of
a rotating structure in space?

I, and I think others on the news group, would be interested in hearing
other ideas about how you could design a space colony.  It is true that
the early ones will be uncomfortable, but once we have an economic base,
I see no reason why second-generation and later-generation ones would need
to be.  You have room, energy, and abundant resources; the real problems,
I think, are going to be engineering problems.  (And, of course, convincing
someone to build it, which is why I have a feeling we'll have to wait
about one hundred years--until we have smart, self-replicating machines
and practical fusion power and a few other things that are possible but
haven't been invented yet--before we see self-sustaining space colonies;
it simply won't be economically feasible to do it until then, I fear.)

Thanks in advance for your help, and your interest.

     Mark Gellis
     f3w%mentor.cc.purdue.edu

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

Date: 20 Nov 89 13:35:36 GMT
From: mcsun!ukc!strath-cs!cs.glasgow.ac.uk!memex![e-mail]  (Peter Ilieve)
Subject: Software for planetary positions wanted

I am looking for some software that will report the positions of the planets
for a given time. The person who is looking for this (not me, I hasten to add)
actually wants to use the results for astrological purposes, so they also
want the positions of the various "houses" according to one or more of
the standard astrological conventions (which I know nothing about).

Please send mail, I will summarize.

    Peter Ilieve        [e-mail]

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

Date: Wed, 22 Nov 89 10:23 EST
From: Mark C. Widzinski <[e-mail]>
Subject: Shuttle Launch Orientation
Supersedes: <[e-mail]>

OK - time out!!!

Before I get any more hate email, I retract the question.
Apparently this topic was discussed already.  However, my mailer
has the AI Embarrassment Package (t) installed and it saw fit to
filter out all Space Digests containing any references to this
discussion.  In private messages, several respondents have
satisfactorily explained the issue at length through gritted teeth.

I apologize to anyone and everyone who was disturbed enough to have
to send me messages like: "AAAAAAAAARRRRRRRRRRGGGGGGGGHHHHHHH!"

Anyway, I have another question.  Why don't we resurrect the Saturn
V booster program?  ;-)

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

Date: 23 Nov 89 04:51:47 GMT
From: gem.mps.ohio-state.edu!samsung!munnari.oz.au!bruce!goanna!minyos!saturn![e-mail]  (Andrew Kemp)
Subject: Planetary Society - summary of responses to net address

Hello netland,

Here is what I have found out regarding my previous posting looking for the
net address of the Planetary Society.

As Tom Neff kindly pointed out, this information might be of interest to
the net as a whole, hence the posting.

As far as I have been able to find out, the Planetary Society does NOT have
a net address. I am unsure as to whether or not there are moves afoot to
correct this. We will have to stay tuned to find out.

With regards to membership renewals expiring, I believe that the Society
will still accept renewals for a "reasonable period" after the due date, due
to the delays in mail and because they really value peoples membership.

So, those like myself who have been getting numerous renewal forms even
though they have sent their renewal in, take heart it will be processed.

Certain individuals out there in netland (I won't name them as I leave it up
to them whether or not they wish to come forward) mailed me with offers of
taking my plight to the Society directly from over there in America.

These individuals were from other space societies, regional coordinators
for the Planetary Society, and helpful individuals. I would like to thank
them for their help. Also, I would like to encourage them to come forward and
make it know that they will provide a means of letting the people of the net
get in contact with the Society.

Finally, I also received queries from a few people who were asking how to
join the Society. As has been stated already, the Planetary Society does not
have a net address, but below is their actual mail address for those who
want it.

    The Planetary Society
    65 North Catalina Avenue
    Pasadena. CA91106

I hope that this helps the people of the net. I know it has helped me. If
anyone has anything further to help people like myself out in regards to this
matter, then please post it.

Regards,

Andrew Kemp
([e-mail]  - ACSnet)

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

End of SPACE Digest V10 #275
*******************