Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V15_3/V15NO348.ZIP/V15NO348

Internet Message Format | 1993-07-13 | 31KB

Date: Tue, 27 Oct 92 05:04:15
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #348
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue, 27 Oct 92       Volume 15 : Issue 348

Today's Topics:
            A career in the Space Program - or Forget It!?
   active planetary probes; should someone update the FAQ (2 msgs)
                   Clinton's bad posting etiquette
                       Comet Collision (4 msgs)
                             Dyson Sphere
                 Gore Blames George Bush for Big Bang
                            melting Vesta
                         nasa shake up rumor?
  pocket satellite receivers (was Re: how much is the 95LX) (2 msgs)
                    Putting volatiles on the moon
                       re HRMS for ETI (2 msgs)
            Smith-Tuttle Comet a threat to earth? (2 msgs)
                       Voyager Family Portrait

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Date: Tue, 27 Oct 1992 00:58:27 GMT
From: Jack Romachek <[e-mail]>
Subject: A career in the Space Program - or Forget It!?
Newsgroups: sci.space

I have been trying to get a job at a NASA center for the past two
years, in particular JPL.  I have very good connections there, but
there appears to be no hope soon of gaining employment.  It is
very frustrating and discouraging.  New layoffs in the SoCal
aerospace industry are announced almost every other day, so I get
the bleak picture of thousands of unemployed engineers with $2000/month
house payments milling around the southland in search of work.
In a very recent article in the San Diego Union-Tribune, a 34-year-old
engineer is going to be laid off from General Dynamics Space Systems
Division this Dec.  He was standing in line with 3000 other people
waiting to be interviewed for 800 jobs at a local large Hotel.
His aim was to get in "hotel sales".

I heard another story about an unemployed G.D. engineer who made $80,000 a
year who was learning COBOL so as to be more marketable as a business
programmer.  Stories like this are not encouraging to the hopeful youth
of america yearning for a spot in the Space Program.

Should I try some new approach to job hunting in aerospace, or should
I totally concentrate on my other interest which is molecular biology?

-----------------------
[e-mail]

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

Date: 26 Oct 92 22:17:42 GMT
From: Henry Spencer <[e-mail]>
Subject: active planetary probes; should someone update the FAQ
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Nick Haines) writes:
>Notice that it doesn't mention Ulysses at all...

Somewhat of an omission, although Ulysses is a *planetary* probe only
by courtesy.  It made a very interesting Jupiter flyby recently, but
its mission is solar astrophysics and related topics.

>... or Giotto, which I believe is still active...

It's in hibernation after its second comet encounter, and will probably
not be revived again -- it's too low on fuel to do much more, and its
next Earth gravity-assist opportunity isn't until the end of the decade.

>... I think that those two complete a roster of 10 probes in solar
>orbits (or escape trajectories) from which we still receive signals.
>Can anyone name any others?

Well, the Pioneer Venus orbiter should have rated mention unless the FAQ
was updated very recently, since it only just died.

Pioneer 6 is still alive, and I think one or two of its later siblings
are too, in near-Earth heliocentric orbits.

>The FAQ also mentions the following plans for possible future
>launches:
>
>Mercury Observer : possibly 1997 launch

I would say that it's vanishingly unlikely that there will ever be another
Observer-series mission.

>Mars Rover Sample Return: possible launches 1996 (orbiter), 2001 (rover)

No chance.  There is interest in more modest unmanned Mars missions, but
the big-ticket sample-return mission is only marginally feasible without
on-orbit assembly (something the unmanned people have a paranoid fear of)
and looks way too expensive for realistic near-future budgets.

>Fire and Ice: possible launch 2001, gravity assist Jupiter, to sun &
>    Pluto (reach Pluto 2016)

No longer at all likely, although fast-track non-Jupiter Pluto missions
are being talked about.

>Cassini...

Still pretty much on track although it's been cut a little bit.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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

Date: Tue, 27 Oct 1992 07:14:08 GMT
From: Ron Baalke <[e-mail]>
Subject: active planetary probes; should someone update the FAQ
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Nick Haines) writes...

[List of active spacecraft from FAQ deleted]

>Notice that it [FAQ] doesn't mention Ulysses at all (which I understand is
>the `Solar Polar' mission), or Giotto, which I believe is still
>active. I think that those two complete a roster of 10 probes in solar
>orbits (or escape trajectories) from which we still receive signals.
>Can anyone name any others? Can anyone tell me whether the Pioneers
>are still alive (or give me launch dates)? Can anyone correct any of
>these dates?
>

Sounds like the FAQ needs to be updated to include Ulysses, Giotto, Hiten and
Pioneers 6-8.  Geotail may even qualify since it made a couple of lunar
flybys recently.  As of a couple of weeks ago, the list would of included
Pioneer Venus.

>The FAQ also mentions the following plans for possible future
>launches:
>
>Mercury Observer : possibly 1997 launch
>Mars Rover Sample Return: possible launches 1996 (orbiter), 2001 (rover)
>Fire and Ice: possible launch 2001, gravity assist Jupiter, to sun &
>    Pluto (reach Pluto 2016)
>Cassini: launch October 97, gravity assists from Venus (21.04.98,
>    20.06.99), Earth (16.08.99), Jupiter (30.12.00), arrive Saturn
>    25.06.04, atmosphere probe of Titan, tour of system (35 flybys
>    of Titan etc).
>

A good portion of the future missions section of the FAQ was based on a
posting that I made three years ago.   Some of the information is obsolete,
and I've been meaning to get it updated.  The approved missions are the
Soviet Mars '94 and '96 missions and the Cassini mission.  Proposed missions
include MESUR, NEAR, Pluto Fast Flyby, and Rosetta.  I'll provide more
details when I update the FAQ files.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | If God had wanted us to
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | have elections, he would
|_____|/  |_|/       |_____|/                     | have given us candidates.

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

Date: Mon, 26 Oct 1992 23:47:15 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Clinton's bad posting etiquette
Newsgroups: sci.space

[e-mail] (Eric Loeb) writes:

[on the subject of Clinton positions incorrectly posted]

We did finally get an apology for bad posting etiquette, even if it wasn't the
most polite I've ever seen (could be that the people mentioned deserved it
though). Anyway, I just wanted to pull out this sentance.  It probably wasn't
meant the way it sounds, but it would explain a lot about the human/robots
debate :-)

>This is an official project of the MIT Artificial
>Intelligence Laboratory, so there are naturally a great many bugs to
>be expected.

--
Josh Hopkins                                          [e-mail]

"We can lick gravity, but the paperwork's a bit tougher."  Wernher von Braun

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

Date: 26 Oct 92 17:59:08 GMT
From: Faust <[e-mail]>
Subject: Comet Collision
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] writes:
>In sci.space, article <[e-mail]> <[e-mail]> writes:
>> I caught the end of a newsclip on SKY TV this a.m. which said that NASA
>> "scientists" (probably the techs. that actually do the real work) had
>> tracked a comet on collision course with the earth - I think it was due
>> to hit us in 2016.  Anyone else hear this, or was I just fantasising it!
>
>When I heard this from my office mate, I was thrilled!  Just picture
>it:  mankind is doomed, and only the space program can save us!  THIS
>is why I joined NASA!  I quickly went downstairs to our coffee shop in
>building 1 (run by a blind guy named Tom) and got change so I could
>pick up a Houston Post.  On the front page, above the fold, is a story
>from Reuter News Service with a "Wilson da Silva" by-line.
>
>"A huge comet is on course to collide with Earth in the year 2116, and
>could kill off most forms of life with an explosion more powerful than
>a million atom bombs, [astronomer Duncan Steel of the Anglo-Australian
>Observatory] told a space conference Sunday."  -- Houston Post, 10/26/92
>
>The date given in the Post is 2116, while the date given in the "SKY
>TV" notice and the date my office mate gave me were both 2016.  No
>NASA people involved in the discovery.
>

  Yes.  The TV reports I saw were pretty garbled affairs, with very
  little in the way of hard information or any attribution of sources.
  Still, I should've known better than to rely on TV news for accurate
  reporting on astronomical/science matters (or anything else for that
  matter).

  After posting my original response, I went away to the library and
  did a little research (i.e. I looked at today's Guardian and last week's
  New Scientist) and found two reports concerning the collision.

  While both of them agree largely with the Reuters report, there seems
  to have been some confusion over the date of the hypothetical collision.
  Both the reports I have read state that the target date for the collision
  is the 14th August 2126.

>
>Of course, the million-nukes and plunge-into-Dark-Ages part of the
>story was front page, but the technical details were on the
>continuation on A-6.  Reading the details, it becomes clear that there
>are no calculations which prove there WILL be a collision, just
>speculation that there MIGHT be a collision on August 14, 2116,
>when Smith-Tuttle's orbit intersects that of the Earth.

  The two reports that I have read propose that the odds against the
  comet colliding with the Earth are 400 to 1.  Still, when facing
  the complete extinction of the race (nay the entire biosphere most
  probably) they're still fairly worrying.

>
>Drat.  I was hoping for the "Comet" movie scenario and a real shot
>in the arm for the space program.  A 2016 collision would be a
>real challenge; 2116 is far enough away that Congress won't feel
>the need for immediate action.
>

  Yeah!  It could have been "METEOR!!!", but for real.  Life imitates
  art once again.

  Square jawned NASA heroes confront the awesome nemesis that threatens
  the very survival of the Earth and of the Human Race.  Steeling
  themselves, they prepare to confront the most deadly part of their
  task:  running the gauntlet of Congressmen hell bent on reducing the
  taxes spent on this 'High Frontier' nonsense.

  If the Comet had been due in 2016 could it have played a part in
  the current Presidential election campaign, which I believe is
  taking place in your fair nation?  How would the three candidates
  have responded I wonder?

  Would the Christian Fundies start claiming it as God's Judgement
  on the human race?  First AIDS...now the Comet!

    ********    ***      **    **   *******   ********  "Quantum Mechanics:
    **         ** **     **    **  **            **      even I don't fully
    ******    *******    **    **  *******       **      understand it."
    **       **     **   **    **        **      **              - Ian Sales
    **      **       **   ******   ********      **    [e-mail]

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

Date: Mon, 26 Oct 92 22:19:45 GMT
From: "John P. Mechalas" <[e-mail]>
Subject: Comet Collision
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (Faust) writes:
>
>  Here are the two reports I managed to uncover concerning the Comet
>  Collision:
>
>  "COLLISION SCENARIO SAYS WORLD TO END IN 134 YEARS"
>
>                                 --  Tim Radford, Guardian Science Editor
>
>  "A huge comet, due to pass close to the Sun in December, could
>  on  its next trip - 134 years from now - collide with the Earth
>  with catastrophic consequences, an Australian astronomer warned
>  yesterday."

               [stuff deleted]

I saw a lot of stuff on this, too.  And it brings up an interesting point.
There have been a lot of scientists in recent years discussing the
possibilities of comets and/or meteors striking the Earth.
   My question:  How hard would it be to deflect an incoming object with,
say, a nuclear explosive?  This theory is one I have heard postulated many
times, and have wondered how easy or hard such a task would be.  The
orbit mechanics aspects could be worked out, I am sure...given enough time.
Plus, the greater the distance, the smaller an orbital perturbation would be
needed to alter the orbit.  But how much warning would we have in such an
instance?

--
John Mechalas                                          "I'm not an actor, but
[e-mail]                                 I play one on TV."
Aero Engineering, Purdue University                     #include disclaimer.h

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

Date: Mon, 26 Oct 1992 22:49:52 GMT
From: Dave Tholen <[e-mail]>
Subject: Comet Collision
Newsgroups: sci.space

In article <[e-mail]>  <[e-mail]> writes:

> I caught the end of a newsclip on SKY TV this a.m. which said that
> NASA "scientists" (probably the techs. that actually do the real work)
> had tracked a comet on collision course with the earth - I think it
> was due to hit us in 2016. Anyone else hear this, or was I just fantasising
> it !

P/Swift-Tuttle has something like a 1/10,000 chance of hitting the Earth
during it's next perihelion passage in 2126 ("the mother of all Perseid
meteor showers").  All depends on how the non-gravitational forces (read
outgassing) adjust the time of its perihelion passage.  July 26 would be
a particularly bad day for the comet to reach perihelion, but it's currently
within the range of possibilities.

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

Date: Mon, 26 Oct 92 22:42:55 GMT
From: Nate Smith <[e-mail]>
Subject: Comet Collision
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]> [e-mail] (John Black) writes:
>
>In "New Scientist", a reputable science weekly in the UK, the collision date
>is down as 14th August 2126. The period is about 130 years according to the
>article. It says the chances of a collision are 1 in 400.
>
>                John Black.

this is the date i heard.  here is another example of the media blowing up
a story and siezing on key words to raise interest at the expense of giving
us useful information.  2016? that would get viewer interest, but 2126 is
further away than the national debt....:-)

- nate

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

Date: 27 Oct 92 04:21:53 GMT
From: John Roberts <[e-mail]>
Subject: Dyson Sphere
Newsgroups: sci.space

-From: [e-mail] (Henry Spencer)
-Subject: Re: Dyson sphere
-Date: 24 Oct 92 02:20:25 GMT

-In article <[e-mail]> [e-mail] (Charles Frank Radley) writes:
->Does a Dyson sphere spin or rotate?

-Depends on the level of technology used to build it.  Dyson's original
-concept -- a cloud of smaller habitats individually in orbit -- obviously
-did.  The problem with a solid sphere is, what *holds it up*?  Even if
-you spin it, that only supports the equator -- what keeps the poles from
-falling inward?

Of course there's photon pressure, which is greater than what would be
available at an equal distance from the sun without the Dyson sphere. It's
not enough to hold up anything really massive, but you could at least
make a thin shell, perhaps holding up localized regions of greater density.
The mass per unit area supported should be independent of the radius of the
sphere.

By the way, in my attempted calculations last week for a sphere with a
diffuse partially reflecting inner surface, I came up with the wrong
formula for the usable photon pressure against the inner surface. I'll
try to fix the equations next week.

John Roberts
[e-mail]

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

Date: Mon, 26 Oct 1992 17:50:46 GMT
From: Jeff Bytof <[e-mail]>
Subject: Gore Blames George Bush for Big Bang
Newsgroups: talk.politics.space,sci.space

>The Clinton/Gore Campaign is like a man trying to bed a beautiful virgin. They
>promise anything that they think can woo her to bed. What usually happens is
>that after the conquest the virgin is discarded as trash. Let this not happen
>to our nation.

>Dennis, University of Alabama in Huntsville

I agree whole-heartedly with this example.  It especially fits the facts
on Clinton as presented in the PBS/Frontline biography aired recently
(one of the most helpful media pieces I've seen in helping to decide
who to cast my vote for - better than the debates).  I hope that there's
still time enough for the Clinton/Perot smoke screen to dissipate.

----------------------
[e-mail]

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

Date: Mon, 26 Oct 1992 23:19:16 GMT
From: Bruce Scott <[e-mail]>
Subject: melting Vesta
Newsgroups: sci.space

The moon would have been largely melted during the collision episode
which formed it, assuming this scenario is correct. I have not seen
collision scenarios discussed vis-a-vis the asteroids, but it at least
seems reasonable to concoct one to explain the Vesta/Ceres problem. One
needs a proof-of-principle run from a simulation. Maybe Benz et al, who
did the smooth particle hydrodynamics calculations for the Moon/Earth
and Mercury collision scenarios could get interested.

Gruss,                                  The deadliest bullshit is
Bruce D. Scott                           odorless and transparent
[e-mail]                 -- W Gibson
Max-Planck-Institut fuer Plasmaphysik

--
   The opinions expressed are not necessarily those of the University of
     North Carolina at Chapel Hill, the Campus Office for Information
        Technology, or the Experimental Bulletin Board Service.
           internet:  bbs.oit.unc.edu or 152.2.22.80

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

Date: Mon, 26 Oct 92 18:39:09 -0600
From: [e-mail] (Phil G. Fraering)
Subject: nasa shake up rumor?

Quoth Josh 'k' Hopkins regarding NASA SHAKE UP RUMOR? on 10-22-92:


J'> Goldin is apparently opening
J'>competion for replacements to outsiders, which has some worried that N
J'>be taken over by DoD and DoE types.

>To feed the rumor mill still further, rumor has it that Richard Truly is
>preparing, once Al Gore takes over for Dan Quayle, to take a White House
>position directing NASA.  This may have something to do with the present
>shakeup.

>Justice served, if you ask me.

Why is Truly good? Are you one of the people who actually enjoys
aspace program that for ten billion dollars a year does nothing but
inflate the price of entering space beyond the reach of private
individuals and "proving" that the cheaper programs we had before,
like Apollo, are impossible?

If Clinton/Gore does this, in ten years we won't have a space program,
just more of these Space Shuttle rides, 1/2 billion for half a dozen
entertainee/astronauts.

And I hope the US remains the third world nation it so obviously wants
to be, wallowing in the mud while the Europeans, Russians and
Japanese, who spent 1/10 the money we did on ASRM to make Gore happy
on liquid air cycle engines instead, go on to the stars.

---

> ~ WinQwk 2.0 a#299 ~ "I can feel it, Dave; my mind. It's
going. Stop, Dave."

--

Buddy, in four years, you're going to _want_ an insanity defense.
Or you'll qualify for one, being one of the happy demented who
think the Space Scuttle program counts as real space exploration,
not remembering that you voted for the party that has said that
they'll shut down all alternative programs.

--
Phil Fraering [e-mail] where the x is a number from 1-5.
Phone: [phone] SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560
---------------------
Disclaimer: Some reasonably forseeable events may exceed this
message's capability to protect from severe injury, death, widespread
disaster, astronomically significant volumes of space approaching a
state of markedly increaced entropy, or taxes.

    The world will end tomorrow.
    NASA scientists note that this was the way the system was
    designed to operate.

    - From the Nov. Focus in Sky and Telescope, on a hypothetical
      NASA press release on something hitting the Earth...

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

Date: 27 Oct 92 03:46:46 GMT
From: Burn Hockey <[e-mail]>
Subject: pocket satellite receivers (was Re: how much is the 95LX)
Newsgroups: comp.sys.hp48,comp.sys.palmtops,sci.space

: There is a GPS receiver for the 95, it probably also uses the serial
: port and would work with other serial devices.
:
Can someone point me to information on this GPS receiver please?

Burn Hockey  [e-mail]

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

Date: 27 Oct 92 04:46:08 GMT
From: Anthony J Stieber <[e-mail]>
Subject: pocket satellite receivers (was Re: how much is the 95LX)
Newsgroups: comp.sys.hp48,comp.sys.palmtops,sci.space

In article <[e-mail]> [e-mail] (Burn Hockey) writes:
>: There is a GPS receiver for the 95, it probably also uses the serial
>: port and would work with other serial devices.
>:
>Can someone point me to information on this GPS receiver please?

Sure.  Since there doesn't seem to be much interest in this elsewhere,
I'm setting followups to comp.sys.palmtops.

GESSA
USA:    615-988-8900, 615-988-6619 fax
CH:    [phone], 3427805 fax

This is from a posting in comp.sys.handhelds in July, I don't know
anything else.  I'm sure there are other GPS receivers with serial
ports with varying degrees of portability.
--
<-:(= Anthony Stieber    [e-mail]   uwm!uwmcsd4!anthony

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

Date: Mon, 26 Oct 92 21:40:50 GMT
From: Dave Jones <[e-mail]>
Subject: Putting volatiles on the moon
Newsgroups: sci.space

Donald Lindsay ([e-mail]) wrote:
>
> I haven't followed all the let's-mine-comets discussions, so maybe
> this one's been done to death already, but:
>
> Why not get rid of earth-crossing objects by deliberately crashing
> them into the Moon?
>
I'd hate to try that and be off by 2.5e5 miles....

> There may be residual volatiles on the Moon, or there may not be. But
> the chances sure would go up if we dumped a six-mile ball of ice
> there.
>
Assuming the debris didn't just splash up into orbit....  Large impacts
at 40 mi/sec don't always do what you want.

--
||Dave Jones ([e-mail]) | Eastman Kodak Co. Rochester, NY   |

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

From: Nick Haines <[e-mail]>
Subject: re HRMS for ETI
Newsgroups: sci.space

Originator: [e-mail]
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References: <[e-mail]> <[e-mail]>
    <[e-mail]> <[e-mail]>
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Date: Mon, 26 Oct 1992 23:03:45 GMT
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Source-Info:  Sender is really [e-mail]

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:

   In article <[e-mail]> [e-mail] (Henry Spencer) writes:

[...]

   Yah, the Fermi paradox is undeniably the more interesting issue
   right now, especially as opinion is converging on planetary systems
   being common and plenty of planets per.
   There is of course the question of evolution of intelligence,
   but I think the dominant factor is lifetime of _communicating_
   civilization - interestingly our single number statistic puts
   the lifetime of order 100 yrs which implies one per galaxy at
   any one time :-(
   But then the inevitable problem is that with that many samples one
   of them should make it to many mean lifetimes and take over
   and we recover the paradox. Curioser and curioser.

I think the P(life evolving) is the least known, or even guessable,
factor in the Drake eqn. From my reading on that, the evolution of a
complex self-reproducing system such as earth life looks very
unlikely. A good introductory book to the current thinking about the
complex process involved is:

A.G.Cairns-Smith, `Seven Clues to the Origin of Life: A Scientific
Detective Story', Cambridge University Press, Canto imprint, 1990,
ISBN 0 521 39828 2.

My guess for P(life evolving | suitable planet) is 1e-12.

Nick Haines [e-mail]

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

Date: 26 Oct 92 16:39:21
From: Steinn Sigurdsson <[e-mail]>
Subject: re HRMS for ETI
Newsgroups: sci.space

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


   In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:

      In article <[e-mail]> [e-mail] (Henry Spencer) writes:

   [...]

      Yah, the Fermi paradox is undeniably the more interesting issue
      right now, especially as opinion is converging on planetary systems
      being common and plenty of planets per.
      There is of course the question of evolution of intelligence,
      but I think the dominant factor is lifetime of _communicating_
      civilization - interestingly our single number statistic puts

   I think the P(life evolving) is the least known, or even guessable,
   factor in the Drake eqn. From my reading on that, the evolution of a
   complex self-reproducing system such as earth life looks very
   unlikely. A good introductory book to the current thinking about the
   complex process involved is:

 ...ref deleted...

   My guess for P(life evolving | suitable planet) is 1e-12.

Well, I disagree, I'd put it at 0.1-1.0 (formally I'd actually
put it at 0.5 if really pressed) but then we have very poor
sampling on that. Maybe further discussion on that line should move
out of sci.space

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

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

Date: 27 Oct 92 02:06:29 GMT
From: "J. D. McDonald" <[e-mail]>
Subject: Smith-Tuttle Comet a threat to earth?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:


>Speed relative to Earth is 50 km/s
Lord Almighty! 1/6 the speed of light!!!!!! ???????

Doug McDonald

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

Date: 26 Oct 92 23:56:11
From: Brian Yamauchi <[e-mail]>
Subject: Smith-Tuttle Comet a threat to earth?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
>In article <[e-mail]> [e-mail] writes:

>The current best solution has it missing the Earth in July 2126,
>but a 15 day delay places it on collision on August 14th.
>As a matter of interest, the best orbit fit for its return once
>it was realised which returning comet it was off by 17 days.

>Swift-Tuttle is
>virtually certain to hit the Earth at some point during the next
>few million years

>As is we can't even rendezvous with
>the thing, would be nice to put a transceiver on it for future
>reference ;-)

Maybe this would be a good justification for reviving CRAF -- complete
with penetrator. :-)

Of course, it's too late for Swift-Tuttle, but surely we can find
another Earth-crossing comet which is posing an imminent threat to
all life on the planet...
--
_______________________________________________________________________________

Brian Yamauchi            Case Western Reserve University
[e-mail]    Department of Computer Engineering and Science
_______________________________________________________________________________

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

Date: 26 Oct 92 22:07:15 GMT
From: Henry Spencer <[e-mail]>
Subject: Voyager Family Portrait
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>>on one of the walls of Von Karman Auditorium across from Voyager 3.
>
>Voyager 3?  A third probe whose mission got cancelled after it was built?
>What would its mission have been?

There was a fairly complete Voyager spare built, I believe -- the last time
NASA did that -- and there was some discussion of the possibility of putting
it into a Jupiter-Saturn-Pluto (I think) trajectory if neither of the "flight"
Voyagers had a launch failure.  It was never an approved mission; remember
that Voyager was originally "Mariner Jupiter-Saturn" -- nothing beyond Saturn
was part of the Voyager primary mission.
--
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  [e-mail]  utzoo!henry

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End of Space Digest Volume 15 : Issue 348
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