Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_7/V13_745.TXT

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Subject: SPACE Digest V13 #745

SPACE Digest                                     Volume 13 : Issue 745

Today's Topics:
               Re: Dark matter
             Re: Slingshot effect
        Re: The economics of flooding a market
              Re: Mars or bust!
            Re: Stafford Commission Report
      Re: Excavating (mining) gold in the space by NASA.
                Re: Space Link
              Re: Mars or bust!

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: 15 Jun 91 03:11:34 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!m.cs.uiuc.edu!ux1.cso.uiuc.edu!uxa.cso.uiuc.edu![e-mail]  (Thomas B MacIukenas)
Subject: Re: Dark matter

[e-mail] (Lloyd E Vancil) writes:

>And I was wondering, why cant "dark matter" be planets, rocks, comets, etc etc?

>  Just  a question...

Well, let's see--
Planets.  These are only a small fraction of the mass of solar systems,
   which are already accounted for, so they can't be the dark matter.
Rocks.  I don't see any reason why not.
Comets.  These are just rocks which get too close to stars, so the same
   comment applies.

The only thing I can think of is that since rocks/comets are formed of
matter which comes from dead suns, maybe what we know about star life
cycles says that not enough rocky material could have been formed already.
--

__ ____ ____ ________ __ __ __ [e-mail]_________________
   \_  _\  _ \  _  _  \  \  \  \  "Does the falcon a creature of the skies
     \   \  \ \  \  \  \__\__\__\   Mourn the passing of it's prize?"
______\__ \____\__\__\__\__\__\__\____________________-Animator____________

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Date: 15 Jun 91 03:21:46 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!spool.mu.edu!snorkelwacker.mit.edu!news.media.mit.edu!media-lab.media.mit.edu![e-mail]  (Marvin Minsky)
Subject: Re: Slingshot effect

In article <[e-mail]> [e-mail] (Les Carleton) writes:
>
>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?).

When a probe passes around a planet the effect is a bit like bouncing
off the planet and, if the planet is coming toward you then you will
leave with (in the limit, which requires a very close passage) an
additional twice the relative velocity.

However, for planetary visits, bouncing off the sun is no use because
it has zero velocity with respect to the solar system, more or less by
definition.   Nevertheless it can be very useful for changing your
direction without comsuning any fuel.

And also there's another way to use the sun, if you're carrying fuel:
fall into the sun and fire the rockets at perigee.  The fuel has
gained potential energy in the fall, and you don't have to carry it

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

Date: 15 Jun 91 03:27:54 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!ub!galileo.cc.rochester.edu!rochester![e-mail]  (Paul Dietz)
Subject: Re: The economics of flooding a market

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

> increases faster than its price decreases.  For example, there are
> greater revenues from corn, wheat, iron, oil etc. in our economy today
> even though the per unit prices of these are lower than in previous
> centuries.  For platinum, this will probably also be true, since it is
> widely used in oil refining, environmental cleanup technology, and
> other important industrial applications.A drop in price could increase
> demand by a much larger factor.

One very interesting application of platinum would be in fuel cells.
For a variety of reasons, cheap platinum would make fuel cell
powerplants for electric vehicles considerably more practical.  In
particular, one could use a direct methanol/air fuel cell, avoiding
the need to handle hydrogen, scrub air of CO2, or thermally reform the
methanol.

Ford was looking at methonal/air fuel cells some years back, but
abandoned the effort when they could not reduce the platinum loading
requirements enough for it to be economical.

    Paul F. Dietz
    [e-mail]

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Date: 14 Jun 91 13:56:42 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!caen!ox.com!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Mars or bust!

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

>    Could any one tell me how to get hold of a copy. Note that I'm in New
>Zealand so there may be some export of technology problems

I doubt very much that there are any ITAR restrictions on the report so you
should have no trouble.

>We won't
>take your nuclear ships and you want to give them to us :-).

Hmmm... they are proposing nuclear rockets.

I would say to get a copy write to the Synthesis Group at:

   Synthisis Group
   1225 Jefferson Davis Highway
   Suite 1501
   Arlington VA 22202

US citizens should write or call their senators or representative. If you
go through them I suspect you can get it for free.

  Allen

--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |   DETROIT: Where the weak are killed and eaten.         |
|   [e-mail]   |                                                         |
+---------------------------------------------------------------------------+

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Date: 14 Jun 91 14:21:33 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!malgudi!caen!ox.com!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Stafford Commission Report

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

>* The panel was dominated by Apollo-era astronauts and engineers.

So? They are all competent engineers well qualified to do the work.

>* The panel made the the first recommendation in any major
>  space commission report that the earth-crossing asteroids could
>  also be a good target for astronaut and automated exploration.
>  The Plan does change, even if much more slowly than the real
>  world.  I'll take good news wherever it comes from.

These quys want to make extensive use of extra-terestrial resources.
Earth-crossing asteroids are a good source.

They will also be using trips to these asteroids as their 'Apollo 8'.
It will be a test run for Mars and demostrate the ability to operate
outside the Earth-moon system.

>* The group recommended revival of Saturn/Apollo technology, as
>  has been discussed in this newsgroup.

What can I say? Great minds think alike :).

>Aside from some details (nuclear power, asteroids) these guys are
>still living in the 60's, I'm afraid.

They are using 60's technology because that is what works best and
cheapest. A desire to use the cheapest technology and then continuously
improve it is not 'living in the 60's'.

>Geezers rocking back and
>forth on the patio, reminiscing about the good ol' days, when
>rockets were big, budgets were bigger, and astronauts had the
>Right Stuff.  Thanks for the memories, gramps.  :-)...

You concluded all that from a two paragraph summary of a 180 page
document? Would it be too much to ask that you actually read it
before forming an opinion about it?

>Any real space buff is also worried about the costs.

What makes you think they aren't? I have spoken with Synthesis people
and others connected with them. They are ALL concerned with reducing
cost.

>>"It's no accident there are no dollars attached to it," said John E.
>>Pike, associate director for space policy at the Federation of
>>American sientists. "People would have sticker shock at the price."

There are a number of good estimates far below the commonly given
estimates. It can be done for less than the cost of Freedom.

>I reccomend yesterday's Wall Street Journal and this week's Aviation
>Week & Space Technology for more complete coverage of the report.

You might also get and read the report itself. Of course, those who
prefer to make up their minds in advance can skip this step.

  Allen

--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |   DETROIT: Where the weak are killed and eaten.         |
|   [e-mail]   |                                                         |
+---------------------------------------------------------------------------+

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Date: 14 Jun 91 20:59:30 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: Excavating (mining) gold in the space by NASA.

{I hate to do this but.....}

In article <[e-mail]>, G E Derylo writes:
>
>  Today's Washington Post reports that an asteroid has been found orbiting the
>Sun at a distance of about 20 million miles from Earth (closest point).  It
>apparently contains 10000 tons of gold and 100000 tons of platinum, as well as

>
>    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.

Yes, it would. But then people would do all kinda nifty things with gold and
platinum, assuming the refined stuff came back in one piece.

>tomarrow in the middle of Nebraska, would do really nastiy things to our
>gold-based (?) economy.

We ditched the Gold Standard years ago. Our currency (as well as those of many
other nations) operates on a "floating" principle of trade in relation to other
nation's supply and demand for our greenbacks (and us for their currency).

I'm not sure any country has its cash backed by gold these days. The Soviets
are looking at backing the ruble in this fashion but they will prob'ly peg
their currency to the Yankee Dollar or let it float as well.

I do not have my econ texts at hand, so you only get the Reader's Digest
version here....


     Signature envy: quality of some people to put 24+ lines in their .sigs
  -- >                  [e-mail]                        < --

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

Date: 14 Jun 91 10:47:29 GMT
From: mcsun!hp4nl!sara5!hasara11![e-mail]
Subject: Re: Space Link

You can also try ames.arc.nasa.gov
anonymous entry
it's got lot's of astro-stuff including software and text/gif
Also the space link
directory: pub\SPACE\SPACELINK
get the index first before you list this directory since it
takes ages (it's DAMN long...)

Bjorn

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

Date: Fri, 14 Jun 91 13:23:34 SET
From: [e-mail]
Comment: CROSSNET mail via MAILER@CMUCCVMA


Date: 14 June 1991, 13:22:51 SET
From: Mike M. Skala             ++39-6-94180-293     MSKALA   at ESRIN
To:   [e-mail]
      [e-mail]



  ESA Press Release No.19; Paris, 14 June 1991

  INVESTIGATION INTO OLYMPUS SATELLITE FAILURE STARTED

  The European Space Agency, ESA, has started an  investigation into the
  origins  of the  loss, early  on 29  May 1991,  of orbit  and attitude
  control of its Olympus Satellite.  In  parallel, ESA  has succeeded in
  gaining additional  evidence on  the status  of the   spacecraft, thus
  improving the  chances for  recovering the  mission  in  a  few weeks.
  Olympus is an advanced  telecommunications satellite  featuring direct
  TV  broadcasting, distance  learning,  various  business  networks and
  several other experimental payloads.

  As already reported, all services have been interrupted since the loss
  of control.  The satellite rotates once every 90 seconds or so, and it
  is drifting eastwards at five dgrees a day.

  Since Olympus  continues to  send short  streams of  telemetry data to
  Earth,  more information   on its   attitude and   the status   of its
  subsystems  has been  obtained in  the meantime.   The  telemetry data
  indeicate in particular that, for the time being,  the solar  array is
  receiving rays from the Sun at a  very oblique  angle; in  a few weeks
  this situation will improve, and it might then be possible to recharge
  the batteries and get commands into the satellite.

  Because  of the  present unfavorable  orientation of  the solar array,
  attempts to  get commands  into the  satellite from  NASA's high-power
  ground station at Robledo near  Madrid (Spain)  were unfortunately not
  successful.

  The Enquiry Board set up to investigate the  cause of  the failure met
  for the first time on 11 June 1991 under the chairmanship of Professor
  Massimo Trella,  ESA Inspector  General.  It  reviewed in   detail the
  events immdeiately  before  and  after  the  loss  of  control  of the
  satellite.

  For reasons that are still not known and are currently  the subject of
  a technical investigation, the satellite ceased to point at  the Earth
  at 0321 hours GMT and went into Emergency Sun  Acquisition Mode, which
  is an on-board automatic safety procedure  that is  activated whenever
  the satellite loses  the Earth  reference signal.   In recovering from
  the emergency to the normal mode, commands were sent to  the satellite
  that  did  not  conform  to  standard  procedures.   It  appears  that
  modifications to those procedures had been introduced in an attempt to
  have the satellite back in normal mode by  0900 EST  for the  start of
  the  broadcasting operations,  but instead  a sequence  of  events was
  initiated thet eventually led  to loss  of control.   However, another
  contributing factor was  the technical  status of  the satellite:  one
  solar array  had not  been active  since January,  and had   the solar
  generator been fully operational the spacecraft would most likely have
  recovered on its own.

  The team specially set up to lead activities to rescue the mission has
  started work, and has been analyzing all  the available  data from the
  satellite  and the  conditions onboard   resulting from   the abnormal
  attitude and  power situation.   At this  time,  it  is  believed that
  salvaging Olympus might  be feasible.   Detailed procedures  are being
  agreed, and the actual  recovery telecommands  will be  initiated in a
  few weeks, when solar illumination will have improved.

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

Date: 14 Jun 91 20:32:35 GMT
From: cbmvax![e-mail]  (Mark Ricci - CATS)
Subject: Re: Mars or bust!

In article <[e-mail]> [e-mail] writes:
>>  concerns among critics who are worried about the huge cost, put at $500
>>  billion or more by some analysts. The report, issued after 10 months of
>>  study, did not mention a price tag.
>
>Numbers like this always make me laugh.  They sound SO BIG!!!  Let's say that
>100 million Americans had to carry the cost in their tax (I don't know the
>exact tax-paying population of America).  We are talking $5000 each.  OK,
>maybe that's quite a lot to wear all at once.  But we are talking over
>20 years before the mission gets off the ground.  Is $250 a year average too
>much to ask?  Heck, I pay more than that (the equivalent Australian amount)
>each year on computer equipment and software alone (and I'm a VERY low-volume
>buyer).  My yearly bus pass costs around that as well.  And not all of the
>cost will be borne by the taxpayer if they get industry support, etc.
>
>Sheesh.

Sheesh yourself, Rhys.  You seem to forget that the US budget is bloated
with far more than NASA's toys.  The $250/year you cite would be added
to the gouging that's already occurring.  For that reason alone, it IS
too much to ask.

Mark
--
=============================================================================
  Mark Ricci - CATS              | "I don't think so! Homey don't play dat."
  Commodore Applications and     |
  Technical Support              |    - Homey the Clown
  [e-mail]     |         In Living Color
==============================================================================

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End of SPACE Digest V13 #745
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