Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v13_7/v13_786.txt

Internet Message Format | 1991-07-04 | 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/ocR2ZWK00WBwEH3E4b>;
          Fri,  5 Jul 91 04:10:10 -0400 (EDT)
Message-ID: <[e-mail]>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Fri,  5 Jul 91 04:10:03 -0400 (EDT)
Subject: SPACE Digest V13 #786

SPACE Digest                                     Volume 13 : Issue 786

Today's Topics:
             Re: Access to Space
               Re: Dark matter
             Re: Mining El Dorado
              GRO status report 5/20/91
             Astro Soc Directory
           Re: Mission status report 6/5/91
               Magellan status reports
              Re: anti-gravity?

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: 22 Jun 91 21:51:08 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Access to Space

In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:

>>No, self-sustaining is not the same thing as profitable...

>Okay, perhaps I missed it in the original post, but how did you come up
>with the statement that comsats aren't self-sustaining?

Let's go back to the original statement. Nick was saying that government
construction of space infrastructure was wrong. He then used the example
of communication satellites as a self sustaining use of space. All I am
saying is that this is not the case; all satellites get lots of subsidies
from those nasty central planners which Nick rails against. Without these
subsidies there would be no space launches at all.

The fact is that there is almost no private launcher development going on
(and the few which are private are dependant on what amounts to government
seed money). Ditto for launch facilites. If the governmrnt dropped all
support the launch industry would colapse. The satellite buisness would
soon follow.

This means that there are no self sustaining space industries today. The
question isn't government support vs no govenrment support rather the
question is how should the government support the creation of an
infrastructure which IS self sustaining. The government has done this
many times in the past and we need to do it the same way today.

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

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

Date: 21 Jun 91 07:48:20 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Dark matter

In article <[e-mail]> [e-mail] (Thomas B MacIukenas) writes:
>[e-mail] (Lloyd E Vancil) writes:
>
>>And I was wondering, why cant "dark matter" be planets, rocks, comets, etc etc?
>
>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.

Bingo! According to the theories postulating dark matter, it has to have
formed around the time of symetry breaking immediately after the Big
Bang. As such, it must be really strange stuff indeed.

Gary

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

Date: 21 Jun 91 07:23:00 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Mining El Dorado

In article <[e-mail]> [e-mail] (Charles (from bbs)) writes:
>How do we mine the El Dorado asteroid ?  Is it one big stainless steel
>nugget, or is it differentiated ?  Either way, I propose blasting it
>to pieces using high explosives.  If it is a homogeneous stainless
>steel nugget I would drill a hole right to the center and insert a
>small nuclear  device.  If it is differentiated, conventional
>explosives might suffice.  Nuclear gives more bang per pound, so
>better than chemical and takes less propellant to send it to El
>Dorado.
>We do not want lots of fragments flying everywhere, all we need
>is to create a powerful shock wave to disrupt the asteroid structure.
>The shock should be small enough that gravity will continue to hold
>the pieces together.   We could literally surround the asteroid with a
>safety net to ensure most of it is retained.    Once shocked the
>pieces can be individually transported or processed by a robot
>smelter.   If it is well differentiated it might be possible to
>visually separate out nuggetts of rare metals, and discard the
>silicates and iron.    A weak acid could dissolve reactive metals (
>alkali earth and alkali metals and iron ) and heavier metals like Gold
>and Platinum would be beneficiated.    If desired the acid solution
>could be electrolysed with low energy to recover the lighter metals.
>Beneficiating by weight might be possible, would have to spin the
> nuggetts in a centrifuge to find out how dense they are.   Each nugget
> could also be scanned by alpha particle back scattering or other
> radio-spectroscopy  means, and then sorted into valuable and less
> valuable bins. Probably cheaper than electrolysis too.  Most efficient
> might be to use minimum size ( ie critical mass only ) nuclear
> charges, and progressively shock parts of El Dorado, that allows more
> margin for error in case we guess wrong about the quantity of shock
> needed - do not want to over do it !    Would need rather a lot of
> diamond drills if it is steel, maybe somebody could design a laser
> cutting torch so we can burn our way in.   How about a deliberate
> nuclear pile meltdown on the surface, the hot pile melts to the center
> via gravity - al la China Syndrome.

The asteroid would have so little self gravity that it wouldn't be
able to hold on to pieces blasted loose, nor would a melted pile
sink to the center in less than geologic time. After a nuclear meltdown,
or even a nuclear explosion, the gold, platinum and nickel iron
would find no market on Earth, and likely no use in orbit for at
least 500 years. Using nukes in this way means you better consider
your investment *very* long term.

In general, I wouldn't want you as mining engineer on my project. :-)
Mining something this big in space is really novel. Nobody's ever
done anything similar and totally new techniques will have to be
developed. Don't let me dampen your speculations, this is really
fresh ground and really practical ideas may sound wild at first
glance.

Gary

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

Date: 23 Jun 91 00:02:02 GMT
From: cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!mp.cs.niu.edu!ux1.cso.uiuc.edu!rs6000.cmp.ilstu.edu![e-mail]  (Eric Behr)
Subject: GRO status report 5/20/91

[even though the reports are supposed to be "weekly", this is the newest
one on SpaceLink...   E.B.]
-----

GRO Weekly Status 5/20/91

NOTE:  This will be the last regularly scheduled status report. GRO
news will be released when significant scientific discoveries
have been made or when it is warranted by the performance of the
spacecraft.



       GAMMA RAY OBSERVATORY (GRO) WEEKLY STATUS REPORT #5
                          May 20, 1991

    The Flight Operations Team in the Payload Operations Control
Center, Goddard Space Flight Center, Greenbelt, Md., reports the
Gamma Ray Observatory (GRO) is performing well.   GRO orbits
Earth at an altitude of 287 x 280 statute miles (462 x 451
kilometers).
    All four of GRO's instruments have been calibrated.  Science
operations began Thursday May 16, 1991 with the observatory
pointed toward a pulsar in the Crab Nebula.  The Phase 1 viewing
plan of the science operations is a full-sky survey expected to
last fifteen months.
    Analysis of the propulsion system pressure transducer and
valve misconfiguration anomalies continues.  The system is stable
and the observatory will continue to be operated in its present
configuration for an indefinite period.  The propulsion system
anomalies do not affect the spacecraft's operation.
        Four detectors in the Imaging Compton Telescope (COMPTEL)
instrument have not been activated at this time, leaving the
instrument at 67% of full efficiency.  The detectors are
experiencing high levels of noise associated with out-gassing.
Out-gassing is a normal process.  One of the detectors will be
activated this week and all four are expected to be activated by
the end of May.  The Flight Operations Team anticipates that
COMPTEL will be functioning at 100 percent efficiency once the
equipment is activated.

--
Eric Behr, Illinois State University, Mathematics Department
Internet: [e-mail]    Bitnet: ebehr@ilstu

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

Date: 22 Jun 91 07:21:22 GMT
From: agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!spool.mu.edu!munnari.oz.au!bruce!monu0.cc.monash.edu.au!vaxc.cc.monash.edu.au![e-mail].
Subject: Astro Soc Directory

Hi, me again.  I'm an inquisitive mathematics honours student, and find
myself often reading scientific papers formy project and other areas of
interest.  Since I last requested help in finding two American scientists,
I was e-mailed by several people giving me their e-mail addressess from
The American Astronomical Society 1991 Membership Directory.  To save me
bugging people all the time, I was wondering if it was possible for me to
get hold of a copy, perhaps there is a version in the form of a datafile
that could be e-mailed to me???

Thanks in advance, The Gryphon...........


    Mick Pope
    Dept of Applied Mathematics, Monash University, Clayton 3168, Victoria
    Australia
    e-mail [e-mail]

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

Date: 21 Jun 91 04:30:27 GMT
From: ucivax!p4tustin!ofa123!p201.f208.n103.z1.fidonet.org![e-mail]  (Mark Perew)
Subject: Re: Mission status report 6/5/91


 > >  [...deleted section...]                    and whether the
 > > seal poses any threat to payload bay doors closing has yet to
 > > be determined.  However, that possibility is considered doubtful.

 > Wow, this biological studies mission seems to have gotten out of hand.
 > Imagine a loose seal blocking the payload bay doors - bark, bark!!  :-)

Wow, these unmanned planetary probe missions seem to have gotten out of hand.  Imagine a partially deployed antenna blocking high-speed communications back to Earth and no astronaut on board to fix the problem - bark, bark!!  (smiley omitted).

- Mark Perew   [e-mail]


--
Mark Perew
Internet: [e-mail]
Compuserve: >internet:[e-mail]
--------------------------------------------------------------------------

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

Date: 22 Jun 91 23:58:37 GMT
From: att!linac!mp.cs.niu.edu!ux1.cso.uiuc.edu!rs6000.cmp.ilstu.edu![e-mail]  (Eric Behr)
Subject: Magellan status reports

Someone asked me to upload some info on planetary missions (from the NASA
SpaceLink BBS). It might be of interest to others, so I'm posting it here.
Some of the reports are quite old, but they are the latest available ones.

-----


MGN REPORT 6/17

                                                      AJS
                                                      6-17-91
                                                      9:00 AM


                    MAGELLAN STATUS REPORT



1.  The Magellan spacecraft is continuing to perform
    nominally.

2.  Electrical power was down in the Denver Mission Support
    area so subsystem engineers are still checking the
    engineering telemetry from the weekend.

3.  The star invalid counter incremented by only three,
    indicating that most STARCALs and DESATs continue to be
    very successful.

4.  Magellan is currently operating in a mode which includes
    two 55-minute hide periods, and using a right look radar
    approach in order to map area around the South Pole.  This
    will continue for the next ten days.


MGN REPORT 6/18

                                                      AJS
                                                      6-18-91
                                                      9:00 AM


                    MAGELLAN STATUS REPORT



1.  The Magellan spacecraft and its radar system are
    performing nominally.  All starcals and desats were
    successful.

2.  The weekly command sequence M1170 will be sent to the
    spacecraft later today.  It will continue the two 55-
    minute hide periods for thermal control, and mapping of
    the area from 45 degrees south latitude to the South Pole.

3.  The next command sequence, M1177,  will shift to left-
    looking radar mapping and 32 minute hide periods as we
    begin to fill in the Superior Conjunction Gap.



MGN REPORT 6/19

                                                      AJS
                                                      6-19-91
                                                      9:00 AM


                    MAGELLAN STATUS REPORT



1.  The Magellan spacecraft and its radar system are
    performing nominally.  All starcals and desats were
    successful.

2.  The weekly command sequence M1170 was successfully
    uplinked to the spacecraft yesterday.  It continues
    the two 55-minute hide periods for thermal control,
    and mapping of the area from 45 degrees south
    latitude to the South Pole.

3.  Next week's sequence, M1177, will shift to left-looking
    radar mapping and 32-minute hide periods as we begin to
    fill in the Superior Conjunction Gap.



MGN REPORT 6/20

                                                      AJS
                                                      6-20-91
                                                      9:00 AM



                    MAGELLAN STATUS REPORT



1.  Magellan spacecraft performance continues to be excellent.

2.  All STARCALs and DESATs yesterday were successful except
    for one star reject on orbit #2415.

3.  Tomorrow spacecraft controllers will perform the routine
    update to the Radar Control Parameter File.

4.  Magellan is now in its 1934th mapping orbit, with over 200
    since we switched to right-look mapping.


--
Eric Behr, Illinois State University, Mathematics Department
Internet: [e-mail]    Bitnet: ebehr@ilstu

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

Date: 23 Jun 91 05:24:53 GMT
From: wdl30![e-mail]  (Donald Ekman)
Subject: Re: anti-gravity?

In article <[e-mail]> [e-mail] (John Stach x6191) writes:
>In article <[e-mail]> [e-mail] (Brett Kottmann) writes:
>>
>>    A researcher in Scotland has developed a device that harnesses
>>gyroscopic energy to lift a device against gravity--antigravity for all intents
>>and purposes.
>>
>> [... details deleted]

Has David Tiberio moved to Scotland recently?

--
Donald E. Ekman, Space Systems/Loral, Palo Alto, CA  [e-mail]

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

End of SPACE Digest V13 #786
*******************