Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_7/V13_761.TXT

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Subject: SPACE Digest V13 #761

SPACE Digest                                     Volume 13 : Issue 761

Today's Topics:
               Re: Launch failure today
        What is the Cheapest Import from Outer Space?
             Re: Mining El Dorado
               Re: Space heros?
               Re: Mars "face"
                   The USF.
              Re: Fred's Operatic Death
               Re: Mars "face"

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]

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Date: 19 Jun 91 04:57:45 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!bonnie.concordia.ca!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Launch failure today

In article <[e-mail]> [e-mail] (Christopher Neufeld) writes:
>   What was this launch? I wasn't aware of any prospectors due up in the
>next little while. While we're at it, what was the launch vehicle? It
>sure didn't look like a Pegasus.

It was a suborbital microgravity launch, being done by OSC's Space Data
subsidiary.  "Prospector" is the name of the launcher, which I think is
yet another of those slap-some-existing-solids-together things.
--
"We're thinking about upgrading from    | Henry Spencer @ U of Toronto Zoology
SunOS 4.1.1 to SunOS 3.5."              |  [e-mail]  utzoo!henry

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

Date: 17 Jun 91 10:18:05 GMT
From: tristan![e-mail]  (Loren Petrich)
Subject: What is the Cheapest Import from Outer Space?


    I was discussing the question of suitable space projects not
too long ago, and I was told that a study had revealed that the
cheapest import from outer space was information(!). For instance, it
is relatively easy to send back, since one can encode radio waves with
it; simply compare trying to send back a spacecraft module with some
physical object(s) on board. And consider that one wants to keep
weight down. It is significant that the most successful space
applications so far have involved sending back information. These fall
into three main categories: surveillance, communication, and
navigation. Into surveillance falls both optical and radar imaging;
electronic intelligence is a cross between the first two categories;
and the information for navigation is position and information derived
from a signal's travel time. Nearly all of the commercial schemes for
new satellite systems fall into one of these categories.

    I note that all spacecraft sent beyond the Moon have only
returned information; sample returns are still in the proposal stage.

    If one wishes to return physical objects, then it is
appropriate to have ones with high value per unit mass, to get around
launch costs. This has been the philosophy of most space manufacturing
schemes so far, which have tried to utilize microgravity to make
quality materials that are difficult to manufacture under Earth-normal
gravity. These include standard-sized beads, crystals, and certain
biologicals (more properly, their purification). Most proposed schemes
follow this strategy also, involving utilizing either microgravity,
high vacuum, or both, to produce materials with high value per unit
cost.

    It is evident here that sending people up into space is
something of a loser. One needs to send up the astronaut, to keep
him/her alive during the flight, and to return him/her safely. All of
these require LOTS of hardware. Reusing some of this hardware would be
valuable; that is the basic motivation behind the Shuttle, and that
has been the philosophy of the space stations that have been sent up
so far (no need to send up a new one each time). The Shuttle's
disappointing performance indicates that outer-space technology may
not be quite ready for ready access to space by human crews. However,
we excel at tasks of perception and manipulation that are still very
difficult to program into computers, and remote-controlled systems can
sometimes get awkward, so there might be some use for astronauts after
all.

    I think that it is worth comparing to the early voyages of
exploration some centuries back, as I had done in a previous article;
the main articles of trade then, like items brought back from outer
space now, were items with high value per unit mass, such as precious
metals and stones, spices (pepper was one hot commodity), and silk.
One could load a very high value of these aboard one's ship before it
starts to sink, as compared to (say) firewood. So weight costs were
important for those voyages, also. Unlike the present situation,
however, information import was only a secondary interest; the main
information that interested most early Spanish New World explorers,
for example, was the location of gold.

    When one considers what kind of crew, the automated option,
which now scores highly, would not be developed for centuries. I'm not
sure of accomodations aboard the Chinese ships, which were rather
large, but the European ships were small and cramped. Even the captain
didn't get too much room by present-day standards. Thus, the European
efforts came close in spirit to unmanned spacecraft, which can be made
VERY light.

    In my previous article, I had compared Chinese and early
European explorations with regard to how they were supported, and
compared them to current space projects. Big prestige projects with
central supporters are impressive, but VERY vulnerable to political
whim and charges of benefiting some select group of fat cats. Smaller
scale projects with less centralized support have much greater
longevity, and are less dependent on any individual success or
failure.

    A final comment about depictions of space travel. Before it
happened, just about every depiction of space travel featured a human
(or some equivalent sentient) crew controlling the craft. I often got
the picture of a spacecraft as a glorified ship or airplane,
controlled by some human pilot. Automated (remote-controlled and/or
preprogrammed) spacecraft were nonexistent, at least in the sample of
early science fiction I have read. Any counterexamples would be
welcome. The closest I can think of was Arthur C. Clarke's proposal
for radio relays in synchronous orbit.

    I think a good parallel is with robots and computers. Robots,
with essentially human perceptual and motor skills, have been a staple
of science fiction and fantasy for centuries. There were no
anticipations of computers, which may be interpreted as disembodied
brains. However, science-fiction writers had no trouble writing them
into their stories when they started showing up in real life.
Interestingly, the "mental" abilities of computers are the opposite of
ours; they excel in minutely detailed bookkeeping, while failing
miserably in simple perceptual and motor tasks. AI systems could
succeed on college-level IQ tests, while failing on kindergarten-level
IQ tests. This is another thing that was unpredicted. That is one of
the reasons for interest in Neural Nets and related architectures,
which sacrifice the apparent sophistication of rule-based inference
for demonstrable success in pattern recognition.

    On space travel itself, planets were usually pictured as the
primary destinations, with spacecraft taking off from and landing on
them. Spacecraft confined to outer space (no landings possible), space
stations and free-flying habitats were rarely depicted before recent
decades (counterexamples welcome here, also). Here again, the present
time features a lot of reversals, with space-confined spacecraft being
nearly universal and the only extended stays by people outside of
Earth being in space stations (something like miniature free-flying
habitats). The only human visits to another large Solar System object
have been to the Moon, and there, only briefly.  Plans for large-scale
human habitation still seem focused on living on the surfaces of
planets and large satellites, though free-flying habitats have
attracted a lot of interest.

    So one should expect the future to have lots of surprises, if
nothing else. Some analogies form the past will work very well, while
others will not.


$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Loren Petrich, the Master Blaster: [e-mail]

Since this nodename is not widely known, you may have to try:

[e-mail]

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

Date: 17 Jun 91 14:41:37 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew![e-mail]  (James Davis Nicoll)
Subject: Re: Mining El Dorado

In article <[e-mail]> [e-mail] writes:
>
>Some issues here:
>
>* We can't use Earth gravity assist or aerobraking for such a large
>  asteroid and unpredictable propulsion scheme.  Therefore, the delta-v
>  is likely to be quite large (several km/s).
>
>* The energy required to achieve that delta-v would likely disrupt or
>  vaporize the asteroid.  For example, to achieve 4,000 m/s the power
>  output is (1e10 kg)(4,000 m/s)^2/(.01 s) = 1.6e19 watts assuming a
>  propogation time of .01 second.  Of course, we could do multiple
>  explosions, but hundreds to thousands of small nuclear warheads starts
>  to get expensive.

    This is probably a stupid question, but is the change in kinetic
energy (and a power rate based on a time value that appears to me to be
arbitrary, unless I missed something) a particularly useful number to
look at? Hmmm. That is phrased poorly. Maybe an example:

    Take a 1 kilo object and change its velocity by 1000 m/s.
That's a change in Ek of 0.5(1 kg)(1000 m/s)**2 or 5 x 10**5 Joules.

    Now, let's assume we're using a rocket to cause the delta vee
which has an Isp of 400. Mass ratio will be something like:

        M1/M0 = e**delta vee/exhaust velocity
              = e**(1000 m/s)/(4000 m/s)
              = 1.28

        If M0 = 1 kg, then
           M1 = 1.28 kg, so we have to throw .28 kg to get our
        delta vee.

        Ek = .5(.28)(4000)**2
           = 2.24x10**6 Joules.

    To power the system we're using, we have to come up with 2.24x10**6 J,
but the change in Ek in the object is only 5x10**5 J, a bit more than a fifth
of the energy we actually use. The ratio between the delta Ek of the object
and the energy we actually use for a given propulsion system goes up as Isp
increases, of course. In your example up above, while the delta Ek is
1.6x10**17 J, the actual energy we'd need would be higher (How much higher
depends on the Isp of the system we use). As an aside 1.6x1017 J is about
the amount of energy we could produce using all the the world's current off-
the-shelf supply of nuclear explosives (Actually, it's two or three times as
much), so we'll need to build more nuclear explosives to move the above rock,
perhaps much more, depending on hw we use them.

    Anyone out there have an idea how much nukes cost per megatonne?

    If there's some painfully obvious reason you used the delta Ek and
the .01 second values you did, take it as written I pound my head shapeless
in contrition.

                                James Nicoll

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

Date: 17 Jun 91 18:30:07 GMT
From: mintaka!think.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!helios![e-mail]  (Sheaf)
Subject: Re: Space heros?

In article <[e-mail]> [e-mail] writes:
>In article <".7-Jun-91.11:13:48.EDT".*[e-mail]> [e-mail] writes:
>>
>>To obtain the
>>public's support, and therefore, an easier time at obtaining public funding,
>>at least a certain degree of the space exploration should be manned...
>
>This is total BS.  The civilian space program was originally motivated
>by the automated IGY satellites, the first being Sputnik which shocked
>the U.S. into funding spaceflight.  The correlation between astronaut
>flights and NASA funding is negative. NASA funding started to drop in
>1966 after Gemini swung into full gear, and dropped most precipitously
>during the Apollo flights which the American public increasingly opposed.
>Polls have always showed roughly equal public support for "unmanned"
>and "manned" endeavors, even when stated with that falsely dichotomous
>terminology.  The myth that astronauts somehow motivate space funding is
>the last refuge for those who can't find any other rationale for the
>wasteful astronaut toys the NASA leadership (astronauts) are pushing.
>

 I agree 100%, Nick, I think the general public (at least from waht I could
 see), was more taken with the VOYAGER encounters than anything else we've
 done since Apollo 11.  The Viking landings as well.  At least to the
 non-scientific people that I know, the results of these missions are
 better known than anything thats been done with the shuttle.  In fact,
 if the Challenger hadn't exploded, most of them wouldn't give the shuttle
 program a second thought now.  I think too many of us think that the public
 is awed by technologies like the shuttle that seem to bring science fiction
 closer to reality, but its been my experience that this isn't really true.
 If anything, they now take it for granted.  I'd say part of the shock of
 the Challenger was that so many people no longer felt that it was still an
 experimental and risky technology.  But the stunning images sent back from
 the outer solar system, that was something that no too many of them (or us)
 could have imagined.  The spirit of discovery isn't just for scientists, and
 the general public is going to see more obvious payoffs from these types of
 missions than from a space station where the payoffs will be much less
 accessable to non-scientists.  Besides, the pricetag on unmanned exploration
 is an awful lot easier for all of us to take.

 S. Sheaffer  -   [e-mail]

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

Date: 17 Jun 91 19:15:26 GMT
From: agate!lima.berkeley.edu![e-mail]  (Bradley K. Sherman)
Subject: Re: Mars "face"

I wonder if there are Martians poring over images of the Grand Tetons
trying to ascertain the meaning of this message from the Earthlings.
----------------------
    Brad Sherman ([e-mail])

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

Date: Tue, 18 Jun 1991 16:50 EDT
From: Is it Friday yet? <[e-mail]>
Subject: The USF.
X-Organization: Southeastern Massachusetts University, North Dartmouth, MA, USA
Comments: A VAX cluster with VMS 5.3-1, PMDF V3.2-19, JNET V3.5 & UCX V1.3A


    Rather than clog up sci.space with more long posts about your charter,
why not post some facts that many of us who might be potentially interested in
joining your organization would need to know first:

    1)  What is the current membership?  What is the composition of this
membership?  You claim to be an international organization, how many members do
you have abroad?

    2)  What governments currently recognize your organization?  Any
international authority you might have is going to have to be acknowledged by
the governments involved, especially if your organization intends to be
militarily neutral.

    3)  What resources does your organization currently possess?  You seem
to have some very grandois plans, do you have the means to carry them out?

    4)  What activities has your organization already begun?  Do you have
any accomplishments to show other than a wordy charter?

    If you have concrete answers to these questions, I would be very
interested in hearing them.  If not, I think you are just wasting bandwidth by
repeatedly posting your charter without actually contributing anything to the
newsgroup.

                        --Matthew Setzer
                          Undergrad Math/CIS Major
                          Southeastern Mass Univ
                          [e-mail]

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

Date: 17 Jun 91 05:53:44 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!mintaka!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: Fred's Operatic Death

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

>The kind of arrogant attitude you project with statements like "astronaut
>groupies" and implying that pro-manned space people call finaciers "Bean
>counters"  makes me discount your arguments.

"Astronaut groupie" is a description based on observations of people
flocking out to Edwards to watch the Shuttle land, getting astronaut's
autographs, and worshipping deceased astronauts as martyrs.  This is
very similar to the behavior of a rock band groupie.   I don't see
any reason to make my language less descriptive of reality.

Some of these people do in fact call the politicians who fund their
programs, and people who keep track of those funds, "bean counters".
_That_ is arrogance.  There have been at least 3 examples of this
perjorative in this newsgroup during the last year.  I encountered it
repeatedly as a member of NSS.   Many do in fact discount scientist's
opinions while claiming that their projects are for "science".   That is
hypocrisy.

The fact that your employer, JSC, gets its revenues via the IRS
for astronaut projects makes me discount your "pro-manned"
statements.  Quit wasting my tax money making self-serving posts to the
net.  Quit wasting my money on engineer-welfare projects like Fred.  Get a
real job.


--
Nick Szabo            [e-mail]
Embrace Change...  Keep the Values...  Hold Dear the Laughter...
These views are my own, and do not represent any organization.

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

Date: 17 Jun 91 12:48:34 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!ptimtc!nntp-server.caltech.edu!sol1.gps.caltech.edu![e-mail]  (Carl J Lydick)
Subject: Re: Mars "face"

In article <[e-mail]>, [e-mail] (Alan Filipski) writes:
>Instead of a bunch of amateur interpretations of this picture, it would
>be interesting to get a professional's opinion.  There are people who
>spend their entire careers interpreting satellite and aerial recon
>photos.  Most of them work for the government, but many are retired.
>Have any of these people given an opinion on the photos?

I've talked to two of them.  I won't try to fit a transcription of about 15
minutes of laughter into this message.  At the end of the laughter, the
comments were something like "I shouldn't laugh.  There are some people who
actually take this SERIOUSLY".
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: [e-mail] | NSI/HEPnet: SOL1::CARL

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

End of SPACE Digest V13 #761
*******************