Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_7/V13_748.TXT

Internet Message Format | 1991-06-30 | 16KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/kcPLC4600WBwQ1uk49>;
          Sun, 30 Jun 91 02:00:36 -0400 (EDT)
Message-ID: <[e-mail]>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Sun, 30 Jun 91 02:00:31 -0400 (EDT)
Subject: SPACE Digest V13 #748

SPACE Digest                                     Volume 13 : Issue 748

Today's Topics:
               Re: Solar Flares
            A Thousand Points of Darkness
               Slingshot effect
               Re: The Un-Plan
      Re: Excavating (mining) gold in the space by NASA.
   Solar Terrestrial Bulletin - Administrivia & Proton Event Alert
            NASA is not the space program

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]

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

Date: 14 Jun 91 17:09:09 GMT
From: mvb.saic.com!astech![e-mail]  (Ken Seymour)
Subject: Re: Solar Flares

In article <[e-mail]> [e-mail] writes:
>A front page article in the British "Independent" newspaper today warns of the
>dangers of severe magnetic storms (as pointed out by the regular solar flare
>postings on this newsgroup).
>
>The British Geological Survey in Edinburgh reported the detection of the shock
>wave produced by an extra large solar flare.
>
>Any reports of actual disturbance from anywhere else on the ground ?
>[We have one (possibly true) story of a Computer Scientist being transformed
>into a Psychologist due to a bit flipping in an admin computer.]
>
>The article also mentions that international computer networks could be
>affected since they rely on satellites to route me%^#.)*{|{@
>
>STF
>--
>[e-mail]                        ...ukc!cs.hw.ac.uk!sfleming
>[phone] x553
>"I saw Sean Connery eating mushroom soup and watching the Repulican march."

Most network communications (including satellite based) are protected by
CRC or similar error detection).  In addition, the transport layer will
retransmit portions of data detected as bad.

Translation:

If a bit gets flipped while travelling through the net, the receiving
host rejects it and requests a resend.  This repeats until the correct
data gets through or the net link is declared down (from two many
errors/to little good data).

Ken Seymour
[e-mail]

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

Date: Fri, 14 Jun 91 10:34:29 PDT
From: [e-mail] (Jim Bowery)
To: crash![e-mail]
Subject: A Thousand Points of Darkness

Herman Rubin writes:
> Radley and Szabo have illustrated my point that the government should
> not be in the business at all.  Different people want different things,
> and have different priorities, and it is important that governments not
> decide what should and should not be done.  Let those who wish to support
> exploration support exploration, those who wish to support man is space
> support it, and those who wish to support welfare project support them.

The most important policy problem in space activities, as well as in many
other policy areas, is distinguishing between genuine market-failures
and pseudo-market-failures that are trumped up by porkbarrel interests
so they can promote communism while wrapping themselves in the flag.

The "thousand points of light" concept of science and welfare is fallcious
for the same reason Jimmy Carter's approach to conservation got him booted
out of office:  When something in the common welfare requires support,
to rely on individual volunteers to provide that support is to sacrifice
the strength of your most altruistic individuals on the alter of the
greedy.  This is an intolerable injustice.  This doesn't mean government
isn't in need of reform.  It is, and desperately so.  It just means
there are some places where we have to bite the bullet and reform
the way government disburses our tax dollars, rather than everyone
turning into flaming libertarians.

On the other hand manned space entertainment certainly deserves zero
government support.  Let the Russians placate their people with State
Circuses and Cosmonauts.  Let's get on with being Americans.

I happen to be something of a socialist because I do believe the
government should provide funding, and lots of it, in areas pertaining to
our "common heritage" such as discovering the properties of nature.
I don't, however, think that just because someone claims, or even
demonstrates, the existence of a market failure, that this is sufficient
justification to start throwing money around.
-----------------------------------------------------------------------------
Jim Bowery      619/295-3164               The Coalition for
PO Box 1981                                   Science and
La Jolla, CA 92038                             Commerce
-----------------------------------------------------------------------------

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

Date: 14 Jun 91 20:31:58 GMT
From: mcsun!ukc!dcl-cs!gdt!brispoly!gould2![e-mail]  (Les Carleton)
Subject: Slingshot effect

Hello all, I am posting this for a friend who has no net access( he's
not convinced by my arguments ... and if truth were known I don't
think i'm putting it across all that well :-) . I will forward replies
to him (both email and followup).

----------------------cut here----------------------------------------

Can you please explain the "slingshot" effect as used on recent
probes. I understand that it increases the velocity of the vehicle by
making passes around the sun. I'm not a physics or Astrophysics major
so it may seem a naiive question. What I don't understand is why the
velocity increases.  Surely if a pass of the sun is made, the energy
conservation law will come into play and the vehicle will end up with
the same velocity at its original distance from the sun as it had when
left there (after launch?).

Pete
[e-mail]1

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

Cheers

...Les...
"Surprisingly happy"
--
+---------------------------+--------------------------------------------+
| Les Carleton              | [e-mail]2 (JANET) |
| MCI#4 Bristol Polytechnic | "My Life - My Opinions - ALL MINE!!!"      |
| Brissle, England          | "I love children ... but I couldn't eat a  |
| "UNIX troubleshooter"     | whole one"                                 |
|    Moving soon ... redirect to [e-mail] after July 1st    |
+---------------------------+--------------------------------------------+

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

Date: Fri, 14 Jun 91 09:28:52 PDT
From: [e-mail] (Jim Bowery)
To: crash![e-mail]
Subject: Re: The Un-Plan

Nick Szabo writes:
> * What is the maximum size and composition that can be safely
fast-aerobraked
>   in Earth's atmosphere.  Currently, the Shuttle (c. 100 tons?) does

At present, I'd say anything that the asteroid mining company can afford
to insure against aerobrake liability.  In practice, that probably means
anything that doesn't rise the present risk from meteors/asteroids to
human population centers by more than a factor of 10 to 100.  It's going
to be pretty difficult to underwrite even that risk.  If, at vertical
reentry velocities, the stuff will really break up and vaporize rapidly
enough to not turn into a stupendous pattern of high velocity shrapnel
on the ground, Loyds might be able to underwrite more than a few tons at
a time.

BTW, I'm not at all convinced this limited liability stuff is the
right way to go on things like airlines, nuclear power plants, etc.
Reform the insurance industry and securities laws before you behave
as though there is an incorrectable failure in the capital/insurance
markets.  Also, as with nuke plants, keep in mind it may be the
thing you are insuring that is the problem.

Earth gravity-assists should be treated the same way.

> >2) Delta-V isn't the overriding consideration -- round-trip mission
> >time is.  As with airlines, costs are dominated by amortization rates
> >on the flight equipment.

> I disagree. "Money-time" is easily computed by the cash flow equation.
> This can be found in a good business calculator, or start up your
> nearest spreadsheet.
>
> Here is a cash flow analysis for a mission that takes 4 years of
> round-trip time.  ...

Thanks for the analysis, Nick.  I can't respond completely right
now because I based my statement on the conclusions of a paper published
in Space Power by Andrew Cutler at the UofA at Tuscon -- a paper I don't
have at my finger tips and which I read several years ago.  I'll dig it
up and try to find the difference between your analysis and his.  You
might also give him a call at 602/322-2997 and talk to him about the
issue.  He will be happy to publish your analysis in "Space Power,
Resources, Manufacturing and Development" if it is correct (he's the
current editor).

I recall Cutler's analysis used optimization algorithms to determine
figures of merit based on observed asteroids.  I think he did make
special mention of 1982DB.  He used one of those scientific/
engineering mathematics programs like MathCAD to model the whole system.

BTW:  It's good to discuss a technical issue that actually promotes
"permanent manned presence in space".  Such opportunities are all too
rare on the net.

> >Due to the probability of our achieving economical fusion in the near
> >future, I seriously doubt SPS will ever be important.
>
> We certainly should not _count_ on it, just as we should not count
> on any other single speculative space industry...
> We need to be ready for another
> Amgen to come along and spoil our plans.   Keep our options open, and
> keep looking for new options.  That's why I called this the "Un-Plan".

I agree wholeheartedly.  I regret if I gave the impression that we should
abandon ANYTHING (except the "big plans" like Tokamak and Fred).  We
do need to be careful about SPS, however.  Especially in the current
environment that is making noises about "economic conversion."  We
could end up with s trillion dollar Fred-like abortion if we aren't
careful.
-----------------------------------------------------------------------------
Jim Bowery      619/295-3164               The Coalition for
PO Box 1981                                   Science and
La Jolla, CA 92038                             Commerce
-----------------------------------------------------------------------------

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

Date: 15 Jun 91 05:26:20 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!news.arc.nasa.gov!skipper![e-mail]  (Mary Shafer)
Subject: Re: Excavating (mining) gold in the space by NASA.

In article <[e-mail]> G E Derylo
writes:

   I'm no economist, but wouldn't the introduction of that much gold
   and platinum into the market *drastically* decrease its value,
   making this a questionable financial venture? Sure, I know these
   materials also have crutial industrial applications, so we're not
   just dealing with jewelry here.

   But we're talking about a cubes of pure gold and platinum 25.53 and
   53.09 feet on a side respectively. I would think this kind of find,
   if it were dug up tomarrow in the middle of Nebraska, would do
   really nastiy things to our gold-based (?) economy.

   Can anyone with some econ background comment on this?

The gold and silver that the Spanish brought back from the New World
messed up the European economy quite greviously.  Galloping inflation,
with too much money (precious metals, of course) chasing too few goods.
This caused a lot of instability, first economic and then political.

The diamond cartel (de Beers) very stringently limits the supply of
diamonds, to keep the price high.
--
Mary Shafer  [e-mail]  ames!skipper.dfrf.nasa.gov!shafer
           NASA Ames Dryden Flight Research Facility, Edwards, CA
                     Of course I don't speak for NASA
            "Turn to kill, not to engage."  CDR Willie Driscoll

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

Date: Sat, 15 Jun 91 00:37:08 MDT
From: oler <@BITNET.CC.CMU.EDU:[e-mail]> (CARY OLER)
Subject: Solar Terrestrial Bulletin - Administrivia & Proton Event Alert
X-St-Vmsmail-To: st%"[e-mail]"

                /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

                        SOLAR TERRESTRIAL BULLETIN

                              15 June, 1991

                          PROTON EVENT RECURRED

                /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\


ADMINISTRIVIA

     Effective immediately, the Solar Terrestrial Dispatch will begin
providing messages with subject headers in upper and lower case.  All
upper-case lettering in the subject headers will only be used for urgent or
important bulletins, alerts or warnings.


SATELLITE PROTON EVENT IN PROGRESS

     A satellite proton event at greater than 10 MeV recurred at 23:40 UT on
14 June.  The flux increased above event thresholds of 10 pfu and is
presently near 20 pfu.  Decay is expected to occur on 15 June, barring
possible proton flaring from Region 6659 (which is now nearing the western
limb).  This proton event should end later this UT day (15 June), provided
major proton flaring does not develop from Region 6659.


**  End of Bulletin  **

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

Date: 15 Jun 91 07:04:17 GMT
From: sequent!muncher.sequent.com![e-mail]
Subject: NASA is not the space program

In article <[e-mail]> [e-mail] (Bill LaSor) writes:

>NASA, warts and all, is the only agency with the facilities
>to launch anything into orbit.

I can hardly believe somebody wrote this.  Wow.  The "NASA is the
space program" myth lives on in the minds of many.  In fact, there
is only one NASA launch vehicle, the Shuttle.  It is illegal (with
loopholes) to launch commercial payload on this vehicle.  There is also
a law called the Launch Services Purchase Act which requires NASA itself
to use commercial launchers whenever possible.   There are extensive
USAF and foreign launch operations.  In all, NASA launches less than 5%
of the satellites going into space.  Welcome to the 1990's!

Here is a short list of non-NASA folks with launch capabilities.  I
am sure I will leave out some:

United States:

* USAF spaceport facilities and the following commercial launch services:

    McDonnel Douglas Corp. (Delta)
    Martin Marietta Corp. (Commercial Titan)
    General Dynamics Corp. (Atlas)

* Air-platform commercial launch services
  (from NASA or USAF B-52 or commercial 747):

    Orbital Sciences Corp. (Pegasus)

* USAF spaceport facilities and launch services:

    Scout (LTV Corp., contractor)
    Titan IV (Martin Marietta Corp., contractor)

Europe:

* French Guinea spaceport and Ariane commercial launch services to
  LEO, GTO, SSO, or deep space.

Soviet Union:

* Glavkosmos launch services (Proton) to LEO, GTO, SSO, or deep space.

China:

* Great Wall launch services (Long March) to LEO, GTO, SSO, or deep space.

Japan:

* Spaceport & H-1 launcher, small satellites to LEO, GTO, SSO, or deep space.


All of these services are less costly for automated payloads than
the Shuttle, which is only economical for carrying astronauts and
astronaut-tended experiments.


>We just may have to continue funding as planned, and hope the
>organization starts to come together in response to public pressure.

Instead of trying to continue "funding as planned", why don't we start
improving those plans and applying that pressure.



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

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

End of SPACE Digest V13 #748
*******************