Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_7/V13_720.TXT

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Subject: SPACE Digest V13 #720

SPACE Digest                                     Volume 13 : Issue 720

Today's Topics:
               Re: NASA Budget
         Earth Gravity Assist and Aerobraking Safety
            Re: orbiter production
    LOW LATITUDE AURORAL ACTIVITY WARNING UPDATE - 10 JUNE
                Microgravity?
      Re: Microsat-EOS (Was:  Re: Fred's Operatic Death)
               Re: Pet Projects
              Re: Microgravity?
     sci.space.policy (was Re: RFD:  talk.politics.space)
      Re: Microsat-EOS (Was:  Re: Fred's Operatic Death)

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: 10 Jun 91 05:28:53 GMT
From: agate!lightning.Berkeley.EDU![e-mail]  (Frank Crary)
Subject: Re: NASA Budget

Nick Szabo implied that the 1957 International Geophysical Year program
contributed to the Sputnik launch and the genisis of the space program.
However, the Sputnik launch was the result of years of Soviet development
of a balistic missile. S. P. Korolyov, who designed both the "Sapwood"
missile and modified it into the SL-1 "Sputnik" orbital launch vehicle
was working towards creating a space program LONG before the 1957 IGY was
planned. The Soviet government was committed to building the missile
lang before the IGY. I do not see how this program (which DID have many
important contributions to science) had ANY impact on the launch of
Sputnik.

                     Frank Crary

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

Date: 10 Jun 91 07:39:24 GMT
From: munnari.oz.au!ariel!ucsvc.ucs.unimelb.edu.au!luga!latcs1![e-mail]  (Jonathan Burns)
Subject: Earth Gravity Assist and Aerobraking Safety

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

> There are several techniques for using Earth to change the orbital
> trajectory of objects:
>
> * fast aerobraking (eg Shuttle, Apollo)
> * slow aerobraking (eg Hiten)
> * gravity assist (eg Galileo)
>
> All three of these can play important roles in reducing the costs of
> capturing space materials from comet fragments and asteroids into
> various Earth orbits.  The delta-v savings are roughly up to an order
> of magnitude for gravity flyby, and up to two orders of magnitude for
> aerobraking.

Apologies for quick, no-research reaction, but:

Is there any percentage in magnetic braking, in which a conducting
body passes transverse to the geomagnetic field, and experiences
drag as the field does work generating eddy currents?

The drag might be << gravitation, but the effect is non-conservative:
the body would lose a little extra kinetic energy on every close pass.

The magnitude of the work is of the same order as that for the conducting
tethers that were lately mentioned here.

A possibly useful complication would appear if the body could be strung
out along a cable like beads, and connected by conducting wire, so as
to intercept more flux.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jonathan Burns        |      Next week this show having new name
[e-mail]|          ! RONOMOTO, ATOMIC GUMSHOE !
Computer Science Dept |     and no Buddhist scriptwriters either....
La Trobe University   |                        -Firesign Theatre
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

Date: 10 Jun 91 12:47:44 GMT
From: sdd.hp.com!usc!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: orbiter production

In article <[e-mail]> [e-mail] (Frank Crary) writes:

>>>Also, I think you are allowing your preference for the
>>>Titan to cause you to ignore the differences between the Titan II, with no
>>>solid fuel strap-ons, and the Titans flying today.

>>Not at all. Which of the differences do you consider relevant?

>SOLID FUEL STRAP-ON [ROCKETS]
>These are a big safty problem (as the space shuttle program found out.)

Unlike the Shuttle, a capsule with an escape rocket whould survive many
failures of solids. At any rate this is a non issue. As I have pointed out
many times the record of the Titan is for all practical purposes just as
good as the Shuttle. If the Shuttle is 'safe enough' then Titan should also
be safe enough.

>In any case, I do not follow the interest in Titan-launched manned capsules.

Because it is a hell of a lot cheaper.

>There are good engineering studies that demonstrate that a 4-man capsule
>should mass only 7 tonnes. If you extrapolate this datum linearly (a bad
>way to do things, but...) then a 20-tonne Titan-launched capsule would
>carry 12 people.

I agree that we will need to build smaller capsules which hold more people.
I use Soyuz and other capsules as an existance proof to show that we can
do the same things for far less cost.

>Do you really need this many? Wouldn't a smaller capsule do better?

At the moment, no. Eventually we will. In the meantime we can use the
extra room to transport bulk supplies.

   Allen


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

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

Date: Mon, 10 Jun 91 09:53:15 MDT
From: oler <@BITNET.CC.CMU.EDU:[e-mail]> (CARY OLER)
Subject: LOW LATITUDE AURORAL ACTIVITY WARNING UPDATE - 10 JUNE
X-St-Vmsmail-To: st%"[e-mail]"

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

                    LOW LATITUDE AURORAL ACTIVITY WARNING

                        UPDATED: 15:30 - 10 JUNE, 1991
                             VALID: 10 - 11 JUNE

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


ATTENTION:

An interplanetary shock from the large class X12+/3B flare arrived at the
earth near 07:00 UT on 10 June.  Major to severe geomagnetic storming
promptly followed.  Activity has continued at major storm levels since then.
A major auroral storm developed during this period and is in progress at the
present time.

There is a relatively high risk for low-latitude auroral activity being
observed over the next 24 hours.  Conditions have materialized which may be
favorable for lower latitude auroral observations.

These conditions should remain for approximately the next 18 to 24 hours.  By
12 June, conditions should decay and become unfavorable for low latitude
auroral observations.


**  End of Watch  **

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

Date: 4 Jun 91 18:33:59 GMT
From: news-server.csri.toronto.edu!torsqnt!lethe!telly!moore!eastern!egsgate![e-mail]  (Herman Rubin)
Subject: Microgravity?


In article <[e-mail]>, [e-mail] (Bev Freed)
writes:

            .....................

> A 710-meter shaft set deep into the Earth forms the centerpiece of a
> new microgravity experimentation facility which will open in July.
> The center is expected to make a significant contribution to
> biotechnology, metallurgy, ceramics, and other space related
> research.

            ..................

I must be missing something.  How do we get microgravity at this depth?
The formula I recall would have the gravitational force there approximately
.9999 g.
--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)   {purdue,pur-ee}!l.cc!hrubin(UUCP)

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

Date: 11 Jun 91 03:56:13 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!acm.rpi.edu![e-mail]  (Greg Moore)
Subject: Re: Microsat-EOS (Was:  Re: Fred's Operatic Death)

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]> you write:
>>
>>       Nick, do you really think we can get 77 microsat-sized and valuable
>>space-rated environmental monitoring sensor packages for only $1 billion?
>
>I am no expert in this field, but at least one environmental monitoring
>satellite, called SeaStar and based on the Orbital Sciences Corp. PegaStar
>bus, is being is being built as we speak.  The satellite costs $10 million,
>and the launch $7 million.  Naively assuming no economies of production

>Using Bozlee's rule for the satellite manufacturing, and keeping the
>launch cost at $7 million each, gives us a total cost of $626 million.
>The cost of the 77 Iridium phone cell satellites (plus about another 10
>for test and replacement) is also projected in the $600-$1,300 million
>range.   If we can use the Iridium bus after Lockheed has already
>designed it and tooled the assembly line we get even more savings.
>
>Note that Iridium includes a very powerful communications package
>which allows for small automobile radio antennas to pick up the signal.
>If we go to a much weaker signal we can use standard backyard satellite
>dishes equipped with automatic fast sky tracking gear, and open up a
>large amount (100 kg?) of payload for the environmental instruments.
>3 dishes in each of 7 planes gives 21 total ground stations.  I suspect
>that won't cost more than a few $million.  We get savings not only
>from a large production run of launchers and microsats, but also from
>retrofitting standard, $5,000 satellite dishes.  Can somebody comment
>on what it takes to get a standard TV satellite dish to track a
>low-earth-orbiting satellite?
>
>
>
>--
>Nick Szabo                [e-mail]
>"If you understand something the first time you see it, you probably
>knew it already.  The more bewildered you are, the more successful
>the mission was." -- Ed Stone, Voyager space explorer

  Nick, aren't we forgetting one major thing here? DATA ANALYSIS!
It doens't matter how you get the data if you can't analyze it.  That
in itself is a costly endevaour.  It's also not one that I can where the
costs can be cut easily.


Carpe Diem                             [e-mail]
                                       [e-mail]
"All that is gold does not glitter."   [e-mail]

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

Date: 10 Jun 91 15:57:41 GMT
From: mentor.cc.purdue.edu!mace.cc.purdue.edu![e-mail]  (Perry G Ramsey)
Subject: Re: Pet Projects

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>>...your pet projects are toast anyway.
>
>Amazing that after hundreds of postings from dozens of people in
>--
>Nick Szabo                [e-mail]

While all this talk of reorganization is hot,
I would like to propose one more group:

sci.space.allen&nick

That way, they can scream at each other all they want. (-:

Seriously, guys, I often appreciate your comments, but I think you're
going overboard.
--
Perry G. Ramsey         Department of Earth and Atmospheric Sciences
[e-mail]  Purdue University, West Lafayette, IN USA
perryr@purccvm
N9LFF

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

Date: 4 Jun 91 21:48:29 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!torsqnt!lethe!telly!moore!eastern!egsgate![e-mail]  (Bob Pendleton)
Subject: Re: Microgravity?


In article <[e-mail]>, [e-mail] (Herman
Rubin) writes:
> In article <[e-mail]>, [e-mail] (Bev Freed)
writes:

             .....................

> > A 710-meter shaft set deep into the Earth forms the centerpiece of a
> > new microgravity experimentation facility which will open in July.
> > The center is expected to make a significant contribution to
> > biotechnology, metallurgy, ceramics, and other space related
> > research.

             ..................

> I must be missing something.  How do we get microgravity at this depth?
> The formula I recall would have the gravitational force there approximately
> .9999 g.

Not a problem. You put the experiment in a high density streamlined
container and you DROP it 710 meters. During the fall you get
microgravity. At the end you get macrogravity. :-)

                Bob P.

--
              Bob Pendleton, speaking only for myself.
   [e-mail] or decwrl!esunix!bpendlet or hellgate!esunix!bpendlet

                         Tools, not rules.

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

Date: 10 Jun 91 06:18:56 GMT
From: rochester![e-mail]  (Brian Yamauchi)
Subject: sci.space.policy (was Re: RFD:  talk.politics.space)

In article <[e-mail]> [e-mail] (Ronald E. Graham) writes:

>This is a Request for Discussion for a proposed new group,

>talk.politics.space

>Charter:

>This group will exist for the purpose of discussion of the politics
>of space exploration, development, and scientific research.  Topics
>could include, but not be limited to:

>o   activities of space activists;
>o   space policy in general, and applied to programs in particular;
>o   funding levels and other non-technical considerations;

[ SETI item deleted ]

While I think separating policy-related postings from technical
postings might be a good idea, the name talk.politics.space sounds
like an invitation to a flamewar.

It would be nice to have a place for rational discussion of space
policy issues related to both government programs and private
enterprise -- sci.space.policy would be one alternative.

As to whether this group belongs in the sci.* hierarchy...  Any
discussion of space exploration and development will be intimately
connected to issues in both science and technology, so this seems like
a reasonable choice -- just as sci.edu and comp.society are not purely
technical groups, but nevertheless deal with science/computer-related
topics.
--
_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Department of Computer Science
_______________________________________________________________________________

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

Date: 10 Jun 91 21:53:10 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!mips!cs.uoregon.edu!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: Microsat-EOS (Was:  Re: Fred's Operatic Death)

In article <[e-mail]> you write:
>
>       Nick, do you really think we can get 77 microsat-sized and valuable
>space-rated environmental monitoring sensor packages for only $1 billion?

I am no expert in this field, but at least one environmental monitoring
satellite, called SeaStar and based on the Orbital Sciences Corp. PegaStar
bus, is being is being built as we speak.  The satellite costs $10 million,
and the launch $7 million.  Naively assuming no economies of production
volume, we get $1,300 million for building and launching 77 satellites.
Using Bozlee's rule for the satellite manufacturing, and keeping the
launch cost at $7 million each, gives us a total cost of $626 million.
The cost of the 77 Iridium phone cell satellites (plus about another 10
for test and replacement) is also projected in the $600-$1,300 million
range.   If we can use the Iridium bus after Lockheed has already
designed it and tooled the assembly line we get even more savings.

Note that Iridium includes a very powerful communications package
which allows for small automobile radio antennas to pick up the signal.
If we go to a much weaker signal we can use standard backyard satellite
dishes equipped with automatic fast sky tracking gear, and open up a
large amount (100 kg?) of payload for the environmental instruments.
3 dishes in each of 7 planes gives 21 total ground stations.  I suspect
that won't cost more than a few $million.  We get savings not only
from a large production run of launchers and microsats, but also from
retrofitting standard, $5,000 satellite dishes.  Can somebody comment
on what it takes to get a standard TV satellite dish to track a
low-earth-orbiting satellite?



--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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

End of SPACE Digest V13 #720
*******************