Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_0/V10_033.TXT

Internet Message Format | 1991-07-08 | 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/usr1/ota/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/YZ3NmUK00jaS422E42>;
          Tue, 12 Sep 89 20:17:37 -0400 (EDT)
Message-ID: <MZ3Nm=[e-mail]>
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Tue, 12 Sep 89 20:17:15 -0400 (EDT)
Subject: SPACE Digest V10 #33

SPACE Digest                                      Volume 10 : Issue 33

Today's Topics:
           Voyager's Interstellar Itinerary
     Re: Galileo Jovian atmospheric probe -- is it sterilized???
             Jumping on the moon
               Re: Face on Mars
        Was Voyager another damaging Apollo one-shot?
             Private launch costs
      Re: Was Voyager another damaging Apollo one-shot?
             RE: Voyager's images
             Re: Message on Mars
----------------------------------------------------------------------

Date:     Fri, 1 Sep 89 11:15 EST
From: <[e-mail]>
Subject:  Voyager's Interstellar Itinerary

Terry Hancock writes:
>>The answer was that in 8,000 years it will fly by Barnard's Star, in 20,000 or
>>so it will pass Proxima Centauri, and then the Oort cloud.
>
>    Okay, so this is completely wrong.

        No, it isn't.  Just incomplete to the point of near
incomprehesibility.  But then, what do you expect from TV commentators.
Their info has been regurgitated and digested so often, there is nothing
left from which anyone can learn anything.  The following is the detail
missing in the above statement, taken from The Planetary Report:

 Year         Event

  8571       Closest approach to Barnard's Star - 4.03 ly away!
             0.42 ly from the Sun.
 20319       Closest approach to Proxima Centauri - 3.21 ly away.
             1.00 ly from the Sun.
 20629       Closest approach to Alpha Centauri - 3.47 ly away.
             1.02 ly from the Sun.
 23274       Closest approach to Lalande 21185 - 4.65 ly away.
             1.15 ly from the Sun.
 26262       Enter Oort cloud.  This seems real fishy to me, especially
             since no one agrees where the Oort cloud actually is located.
 28635       Exits Oort cloud and Solar System.
129084       Closest approach to Ross 154 - 5.75 ly away.
             6.39 ly from the Sun.
296036       Closest approach to Sirius - 4.32 ly away.
             14.64 ly from the Sun.
442385       Closest approach to 44 Ophiuchi - 6.72 ly away.
             21.88 ly from the Sun.
957963       Closest approach to DM+27 1311 - 6.62 ly away.
             47.38 ly from the Sun.

        Personally, I wouldn't trust the numbers past about 60000 years -
there are still too many unknown possibilities for gravitational influences.

 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
|  Arnold Gill                          |
|  Queen's University at Kingston       |
|  BITNET:    gill@qucdnast             |
|  INTERNET:  [e-mail]  |
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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

Date: 1 Sep 89 22:43:31 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Galileo Jovian atmospheric probe -- is it sterilized???

Re: the Galileo contamination threat, I agree it would be a terrible
mishap to infect Jupiter (and buddy, if there ARE beings there do you
want to get them mad at Earth?!!), but I suspect the worriers are
missing the event sequence.  My understanding is that most agree any
exterior microbes will be 86'd en route and during entry; that the
surviving ones would be in the probe interior.  The probe will pass
through possibly viable zones, and will also be crushed in the
atmosphere so as to breach the interior, BUT it will long since have
left the viable zones before being crushed.  In the viable zones it'll
just be a falling cone of metal whizzing by between lethal gases.  There
shouldn't be too much opportunity for infection at that point.

I also think we shouldn't take too much responsibility for keeping
Jupiter pristine.  Junk flies all over the solar system, as witness the
Mars "sample return missions" to the Ross ice shelf.  Jupiter's probably
seen it all before.

Let's just hope we don't get a huge JOVIAN probe cone-ing down into
our atmosphere in retaliation a couple of years from now! :-)
--
Annex Canada now!  We need the room,    \)    Tom Neff
    and who's going to stop us.        (\    [e-mail]

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

Date: Fri, 1 Sep 89 19:50:34 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Jumping on the moon


Several people have recently posted calculations of how far it would be
possible to hit a golf ball on the moon. A more interesting (to me :-) problem:
how high would it be possible to jump on the moon? Assume a pressurized
gymnasium with a solid floor, and ignore wind resistance. (If that bothers
you, assume a pure oxygen atmosphere at 1/5 standard pressure, which would
greatly reduce resistance.)

By experimentation, I have estimated that it would not be too difficult for
a typical healthy person on earth to make a standing jump of 1.5 feet (raising
the center of gravity by that amount. A person jumping on the moon and leaving
the floor at the same velocity could jump about six times as high, or about
9 feet. However, much of the energy of a jump on earth goes into counteracting
the force of gravity during the initial acceleration, while this effect would
be greatly reduced on the moon. There is a limit to how fast the legs could
extend even under a reduced load, but I estimate that it should not be too
difficult to double the initial velocity, which would make it possible to
jump about 24 times as high on the moon as on earth, or about 36 feet (!)

It is also apparent that it would be much easier to get injured or killed
trying this experiment on the moon, since the total "hang time" would be
increased from about .6 seconds to about 7.4 seconds, allowing plenty of
time to rotate and land sideways or upside down, at a velocity of about
20 feet per second. Visitors to the moon will have to learn free-fall
maneuvers before they attempt gymnastic routines.
                                        John Roberts
                                        [e-mail]

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

Date: 1 Sep 89 21:39:52 GMT
From: agate!codon1.berkeley.edu![e-mail]  (Mary K. Kuhner;335 Mulford)
Subject: Re: Face on Mars

In article <[e-mail]> [e-mail] (James P. Galasyn) writes:

>I was not impressed by the abstract posted here awhile back.  A couple
>year ago, _Omni_ printed an article about the Face, full of beautiful
>computer-enhanced images of the thing, but I figured that it could be
>an accident if that's all there was:  a Face in the desert.  Also, it
>was _Omni_.

There is a big problem with computer enhanced images of the Face,
as pointed out by an article in _Skeptical Enquirer_ last year.
The original transmission was digital; it gave a darkness for
each pixel in the screen.  If you see an original it is clear that
certain pixels came out black for transmission-failure reasons.

Logically, what can computer enhancement do with such a picture?
It can fill in the black pixels with their adjacent color, which
definately makes the picture look better.  Other than that, it is
not obvious that the picture can be improved.  Where is the new
information coming from?  Computer enhancement is good at removing
regular static or at making small differences of shade larger,
but that's not what is wrong with the Face picture--it just doesn't
have enough pixels in it to show the object very clearly.

Mary Kuhner
[e-mail]

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

Date: 1 Sep 89 22:32:40 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Was Voyager another damaging Apollo one-shot?

This is an heretical thought, but I wonder if the Grand Tour wasn't
the unmanned equivalent of the Kennedy space race and its resulting
one-shot lunar landing program -- in the sense that, having rushed
ahead to grab the dessert, we found ourselves in no mood to continue
eating our vegetables, i.e., building a solid and lasting program.

I mean after all, think about it -- NOW what can JPL do that will grab
the attention of the man in the street?  We've crammed the joy of
discovery of every major planet into the space of about 15 years.
Everything else from now on is going to look boring or repetitive by
comparison -- oh, ANOTHER picture of Jupiter on the front page, Martha,
didn't they do that a couple of years ago?  The Apollo 16 Syndrome.

Now impressing the man in the street isn't the #1 priority of planetary
exploration, natch -- it's scientific knowledge.  But the bucks could
be hard to come by.  I'm just a little afraid that NASA has managed to
outsmart itself by doing such a comprehensive job with a couple of
probes.

Just pray *we* don't pull a FOBOS number or things will get VERY tough.

--
Annex Canada now!  We need the room,    \)    Tom Neff
    and who's going to stop us.        (\    [e-mail]

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

Date: Fri, 1 Sep 89 20:23:06 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Private launch costs


>From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
>Subject: Re: Re: Contractors

>In article <[e-mail]> [e-mail] (John Roberts) writes:
>>still considerably different from the claims by some people that the
>>expansion of private launch services will almost immediately cause launch
>>costs to drop by a factor of 50 (or 100 or 1000).

>Have you heard anyone claiming that?  I haven't.
By the more responsible contributors to the list, trying to make a serious
estimate, no. As wild exaggerations, or as a necessary corollary to some of
the proposals (such as growing food crops in orbit for use on earth), yes.
There sometimes seems to be an implicit assumption that nearly all of the
cost of a government launch is from bureaucratic red tape, "excessive" safety
and reliability measures, and deliberate overpricing (all of which may be
somewhat true), and that private launch companies (being entirely free of all
of these problems :-) would immediately lower launch costs to a tiny fraction
of their current rates. I get the impression that those on the list who have
given the matter more thought hope that prices will go down by a factor of
ten or so within a few years, which I would consider very optimistic but
still possible. Since private launch services are really just getting started,
price trends should be a lot more obvious in two or three years.

>What I have heard, and
>have claimed, is that such cost reductions are well within the bounds of
>possibility within, say, a decade, given a solid competitive market with
>volume, say, comparable to that of the USSR's normal launch schedule.
>We don't have that yet.
Those who like to describe the advantages of the Soviet space program point
out the extreme importance of economies of scale in obtaining inexpensive
launch services. Looking at unmanned launches (the market for private launch
services in the forseeable future), the USSR owes nearly all of its launch
volume to military missions. What are the most plausible scenarios for
increasing the US launch volume to a high level in the near future? An
increased military presence in space such as SDI is one possibility, but
many space enthusiasts would find it distasteful to push for this in the
hopes of lowering launch costs. The commercial market is still fairly limited,
though lowering launch prices *before* launch costs come down (in other words,
subsidies from the government or from existing large corporations) could
increase its rate of expansion. Using private launches for most of the parts
of a space station (NASA or other) is another possibility. Perhaps NASA could
concentrate on putting together a large number of inexpensive space probes
(rather than a few expensive ones) in order to raise the total volume (they
may be thinking about this already).

Another problem: the USSR has just one "company" to supply all its launch
needs. If the US has 10 private launch companies, will it have to have 10
times the USSR's launch volume for all the companies to have good economy
of scale?
                                   John Roberts
                                   [e-mail]

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

Date: 2 Sep 89 03:28:56 GMT
From: uhccux![e-mail]  (Jeff Goldader)
Subject: Re: Was Voyager another damaging Apollo one-shot?

In article <[e-mail]> [e-mail] (Tom Neff) writes:
>This is an heretical thought, but I wonder if the Grand Tour wasn't
>the unmanned equivalent of the Kennedy space race and its resulting
>one-shot lunar landing program -- in the sense that, having rushed
>ahead to grab the dessert, we found ourselves in no mood to continue
>eating our vegetables, i.e., building a solid and lasting program.
>
>I mean after all, think about it -- NOW what can JPL do that will grab
>the attention of the man in the street?
>
>Now impressing the man in the street isn't the #1 priority of planetary
>exploration, natch -- it's scientific knowledge.  But the bucks could
>be hard to come by.  I'm just a little afraid that NASA has managed to
>outsmart itself by doing such a comprehensive job with a couple of
>probes.
>
>--
>Annex Canada now!  We need the room,    \)    Tom Neff
>    and who's going to stop us.        (\    [e-mail]

Fer cryin' out loud, Tom, **WHAT DO YOU WANT**?!?!?

Would you prefer that we never learned anything about anything just
because someone would then figure we knew it all about everything?

We have just *barely* scratched the surface with the Voyagers.  You
saw those Triton images, right?  Well, that is only *25%* of the
surface of the satellite.  We barely looked at Nereid.  We haven't
obtained decent resolution (sub-km) for almost all of the satellites
Voyager saw.  We haven't done any long-term studies of the weather
of the Jovian planets, we haven't (yet) sent probes into any of
their atmospheres, we haven't snooped around their ring systems with
orbiters, we haven't obtained any in-situ infrared imaging.
We haven't sent landers down to any of the moons yet (and have
plans to do so only in Titan's case)...

I could go on for hours!

These are all *incredibly* exciting things!  Comprehensive?  Heck,
this is just a first tantalizing glimpse!

I think (from some of your previous postings) that you would
really like to see these things; I'm not accusing you of
being against exploration, far from it.  I am just trying
to give some reasons that, not only are we not finished, we
have just barely started.

Anyone want to see a Neptune orbiter in 2018?  We can do it if
we launch in 1998, according to Andy Ingersoll (sp?) of the Voyager
imaging team.  If you want some action, call your congresscritters,
thank them/press them for their support of CRAF/Cassini, and tell
them that, with a duplicate of Cassini, we can have a Neptune orbiter.

It takes a long time to get to the planets.  Now that we have
Galileo and Magellan going, and very probably CRAF/Cassini, we
need to start looking at follow-on missions.  Voyager was the
initial reconaissance; now, let's do the real work!

Jeff Goldader                        University of Hawaii
uhifa.ifa.hawaii.edu                 Institute for Astronomy

"So, Lonestar, now you see that Evil will always win- because Good is stupid."
-The Dark Lord Dark Helmet, _SPACEBALLS_

Disclaimer: The opinions expressed herein are my responsibility alone.
The University of Hawaii and the Institute for Astronomy neither support
nor are in *any way* responsible for these opinions.

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

Date:         Fri, 01 Sep 89 11:01:26 EDT
From: Walter Giesbrecht <[e-mail]>
Subject:      RE: Voyager's images

In response to the query regarding the availability of Voyager images
from NASA, there was mention in the June 1988 issue of Byte that some
of this stuff was available on CD-ROM. Specifically, there are two
discs -- one featuring images of Uranus, and the other featuring data &
images from all over the solar system. The product is (was?) known as
"Planetary Data System Space Science Sampler", and is available from

NASA JPL
4800 Oak Grove Dr.
Pasadena, CA 91109
[phone]

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

Date: Fri, 1 Sep 89 10:03:56 PDT
From: Peter Scott <[e-mail]>
Subject: Re: Message on Mars

In article <[e-mail]>, [e-mail] (William Baxter) writes:

> I have before me a post card which bears the profile of John F. Kennedy.
> The startling likeness is a rock formation on the island of Maui,
> Hawaii.

JFK certainly gets around.  There is a rock near Colorado Springs which looks
just like him.  I don't know if there are postcards, but it is signposted.

There are many rock formations on Earth that resemble real objects much better
than anything on Mars (town near here: "Eagle Rock"; guess why).  Just
wind and water erosion.  Same elements are/were available on Mars.

Peter Scott ([e-mail])

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

End of SPACE Digest V10 #33
*******************