Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_1/V10_152.TXT

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Subject: SPACE Digest V10 #152

SPACE Digest                                     Volume 10 : Issue 152

Today's Topics:
             A small voice, a small plan
     Re: Trying to build a fluxgate magnetometer -- help!
        Re: More whining about Galileo (nope)
            Re: More whining about Galileo
             re: plutonium aboard galileo
        Re: Galileo--- history repeats itself
          Amroc Helium Pressurization system
               Re: Leap Second
         Re: Titius Series / Quantum orbits?
----------------------------------------------------------------------

Date: 13 Oct 89 23:40:41 GMT
From: oliveb!mipos3!omepd!inteloa![e-mail]  (David P. Schneider)
Subject: A small voice, a small plan


[I originally posted this under the subject line,
"Subject: a small step for a goal-setter, a giant leap for planning..."
but  decided  afterwards that  that  was  too facetious.  Since I apperent-
ly screwed up the distrbution, I can still hope that you see only this copy.

                                                    dps, Friday          ]

My own space  goals  are  to  experience  the  adventures  Robert  Heinlein
described  so  beautifully  to  teen-agers of the 50's and 60's (I was into
aircraft then, too, and I have yet to take a flying lesson).   But  to  ad-
dress a more practical set of goals, how about the following?

Design the space station for intermittent occupation.
        Perhaps the Spacelab module could be  modified  to  provide
        crew  quarters for visits of 2-6 weeks, assuming provisions
        seperately launched.  Permanent parts of the station  would
        be  for  maintaining orbital stability, power, and untended
        experiments.  Actually, the untended experiments  are  most
        likely to go up in medium-term modules.

        I've had wild pictures of plugging the Spacelab module into
        an  ET,  then  filling  the  tank  with water for shielding
        (cosmic rays). But what  could  be  done  realistically  to
        shield Spacelab to a reasonable level?

        The current space station plans are based on not losing any
        shuttles  or station components over a lengthy construction
        period.  It would be a good idea if  we  could  reduce  the
        risk  to the project by making components replacable (e.g.,
        reducing their cost) and by reducing the number of  flights
        required to make a stable platform.

Re-assign the shuttle fleet.
        Assign N-1 shuttles to manned  flight  support  (currently,
        N=3).   Assign  the  Nth shuttle for experimental equipment
        tests.  That is, it would be used to test new SSME designs,
        new  control  equipment, etc.  If the design change is suc-
        cessful, roll it back into the support pool, and  pick  the
        most  out-of-date  orbiter  to try the next change on.  One
        problem with this is that structural changes  probably  re-
        quire a new airframe.

        Already there has been some of this going on.  Remember how
        each  new  orbiter has been better than the previous?  Such
        as using thermal protection blankets to replace many  areas
        of tiles?

        Question:  could the current shuttle be adapted to  a  hor-
        izontal  launch  system, or is better lift required than is
        available?

Of course, I want to continue planetary probes.  I don't have any  specific
suggestions,  but the current trend to smaller satellites may also help the
probes.  The idea is to launch a fleet of small, specific, and hence  cheap
probes  by  pointing  out  how  each one saves money over a general purpose
multi-mission unit.  Of course, the  cumulative  costs  may  not  be  lower
(probably  higher), but if funding is cut for 50% of a fleet, you're better
off than if funding is cut for a  single  multi-mission  unit.   Also,  the
design trade-offs become easier.

Anyway, a shot from someone with no deep insights and no inside  knowledge.
I don't even have an regular science subscriptions outside of the net.

                                                David P. Schneider
                                                     BiiN (tm)
                                                  Tuesday, 10.10

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

Date: 13 Oct 89 18:42:27 GMT
From: rti!tijc02![e-mail]  (John Leroy )
Subject: Re: Trying to build a fluxgate magnetometer -- help!

From article <[e-mail]>, by [e-mail] (Mark A. Haun):

>
> I am trying to build a fluxgate magnetometer sensitive enough to
> monitor variations in the Earth's magnetic field, mostly to observe
> magnetic storms caused by big flares on the sun (March 13, 1989
> stuff especially :-) !).
>
> I would appreciate hearing from anyone who has built any sort of
> fluxgate magnetometer, anyone who has seen a construction article
> for one, or anybody with suggestions/ideas/etc. on the feasibility
> of this project.  Please email to any of the addresses below.

My email to you bounces, so I'll post this.
I just stumbled across "Simple Magnetometers or How to Measure Your
Own K-Index" by Russell G. Wicker, W4WD in the Proceedings of the
22nd conference of the Central States VHF Society (1988). If you
want a copy and can't find the proceedings let me know.
--

        -John LeRoy

Packet Radio:     WA4VLV @ WX4S
Compuserve: 74136,401
UUCP:   rti!tijc02!jkl141
Phone: [phone]

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

Date: 16 Oct 89 04:13:24 GMT
From: gem.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!jhunix![e-mail]  (Ta06)
Subject: Re: More whining about Galileo (nope)

In article <[e-mail]> [e-mail] (Christopher John Rapier) writes:
>Actually, The Christic Institute is more than an environmental impact
>group. They are actually a liberal law frim doing what they consider
>good work on a pro-gratis basis. They are a lot like, from what I
>understand, the ACLU. They are voicing a valid concern. 40 pounds of
>plutonium ain't just a chest X-Ray. A couple mics will give your brain
>them funky tumors.

Yes.  Al you have to do is cut open someone's head, put the plutonium in, and
close them up, and they might get brain tumors from it.

Alpha particles are not very penetrating.

_Why_ do so many people post from ignorance?

>I personally don't agree with them on this BUT I do
>support them in their investigations into the actions of the CIA and the
>government in Nicaragua and the Palenca bombings ...

La Penca.
--
"The workers ceased to be afraid of the bosses.  It's as if they suddenly
 threw off their chains." -- a Soviet journalist, about the Donruss coal strike

Kenneth Arromdee (UUCP: ....!jhunix!arromdee; BITNET: arromdee@jhuvm;
     INTERNET: [e-mail])

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

Date: 16 Oct 89 03:37:32 GMT
From: [e-mail]  (Terry Hancock)
Subject: Re: More whining about Galileo

In article <[e-mail]> [e-mail] (David B Wilson) writes:

>2) How does a planet capture an asteroid?  Sling shot effect in reverse
>   with a moon or two to help out?
>
    This isn't so mysterious.  I assume you're having trouble because
it is difficult to have such a thing happen in the two-body problem (an
object approaching from infinity will recede to infinity, it can't have
a closed orbit).  However, the problem is really best considered as a
restricted three-body problem, with the Sun and the Planet being the
two substantial masses and the captured asteroids the negligible-mass
object which may follow a very complicated orbit if you get it in the
right place.

    The asteroid starts from (approximately) a two-body orbit around
the Sun.  As the planet perturbs the orbit, it eventually reaches an
unstable orbit from which it must be treated as a three-body problem.
Then it settles into a more or less stable two-body orbit around the
planet -- having "passed the hump."  It may then be perturbed into a
tighter orbit (probably by tidal effects) which will then be more
stable, or it will be perturbed back over the hump and into solar
orbit.

    The grouping of Jupiter's outer satellites into two families
suggests to me that the details of this problem are probably pretty
interesting, but to my knowledge this has not been explained, and
I don't happen to know of anyone who's studying it (anyone know?).


>
>Q: How many members of the Christic Institute does it take to screw in a
>   light bulb?
>A: 21.  1 to screw it in and 20 to perform the environmental impact study.

    Cute :-).  But I'd rather you didn't put down environmental
impact studies -- they're very important, even when they say everything's
OK after all.  Most of the time, the point is to find the minimum-impact
way of doing what you want, not putting you out of business.  And when
they DO put you out of business, it's usually for a good reason, though
you probably won't appreciate it then.  Uncontrolled industry is a
dangerous thing, we all have to face the Human future -- Space flight
is one way, Environmentalism is another, and we need both.
    PS -- This is not to say I support the Christic Institute,
I think they're full of ....

***************************************
Terry Hancock
[e-mail]
***************************************

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

Date: 16 Oct 89 14:31:10 GMT
From: f.gp.cs.cmu.edu![e-mail]  (Bret Musser)
Subject: re: plutonium aboard galileo

Re: danger of plutonium

It is only dangerous when not handled properly, which NASA has provided
sufficient data to the EPA and to the courts saying that they are
handling it safely.

For those who like examples:

(From Academic American Encyclopedia under Plutonium -- Uses)
     "The isotope (238)Pu powers such sophisticated devices as
      batteries in implanted heart pacemakers, which consequently
      operate for up to 10 years."

I'll let you draw your own conclusions.

bjm
.sig ahead!

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Bret J. Musser   ---   Carnegie-Mellon University | Why bother with dis-
                             Pittsburgh, Pa       | claimers on rec.arts.-
Internet: [e-mail]                     | startrek?  Do companies
Bitnet: bjm%f.gp.cs.cmu.edu@cmccvb                | hold official policies
Work Phone: [phone]                        | on TOS vs. TNG?
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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

Date: 12 Oct 89 15:39:45 GMT
From: gem.mps.ohio-state.edu!uakari.primate.wisc.edu!pikes!udenva!isis!csm9a![e-mail]  (Joe Applegate)
Subject: Re: Galileo--- history repeats itself

In article <[e-mail]>, [e-mail] (Mark Robert Thorson) writes:
> The Christic Institute is (or was) on the net;  I remember seeing some
> postings from them in sci.environment.  Perhaps someone could post their
> net address and invite them to give a statement?  (Perhaps sci.space.flame
> could be created in advance for this purpose?)
>
> I thought I heard that they are funded by a number of Christian churches,
> hence the name.  Of course, this could just be a cover story.

I have heard that they are funded by various New Age and several extremely
liberal "Christian" denominations... and that their calling is to bring the
"Christ" consciousness into politics... this is of course New Age theology
and has no resemblance to Biblical Christianity.

I would appreciate any real information as to the theology and specific
supporters of the Christic institute as I am going primarily on hearsay...

               - Joe Applegate -

    ======================STANDARD DISCLAIMER============================
     All views and opinions are my own and do not represent the views or
     opinions of the Colorado School of Mines, whatever they might be.
    =====================================================================

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

Date: 12 Oct 89 06:11:19 GMT
From: zephyr.ens.tek.com!tektronix!psueea!parsely!bucket!loop![e-mail]  (Keith Lofstrom)
Subject: Amroc Helium Pressurization system

More information about the AMROC LOX tank pressurization system:

The pressurization tanks contain a mix of room temperature helium and
hydrogen gas at 6000 PSI.  This mixture leaves the tank and expands
adiabatically to 400 PSI or so.  This cools the gas down a lot, so it
doesn't expand as much as it would if it stayed at room temp, or was heated.
The gas mixture    passes over a bed of (Platinum?) catalyst, combines
with ambient oxygen (this is the LOX tank, remember) and heats up
to 700K or so; this yields about 10x the volume of pressurized gas.
Of course, when the gas hits the LOX  and the tank walls it starts
cooling again;  I don't know how fast that process is, or whether
sloshing in the tank would accelerate it, but apparently the effect
wasn't large on the test stand.

- - - -
In reply to Henry about the safety of LOX:  Of course the LOX is just
as dangerous on a hybrid as it is on a liquid;  but it is explosions
from the rapid mixing of fuel and oxidizer in a liquid rocket accident
that AMROC points to as a danger.  The LOX can't rapidly mix with the
hybrid fuel, though of course it can still support combustion in
the wrong places.  Fires are (as demonstrated) still a threat -
large explosions aren't.  This will hopefully lead to lowered
costs for pad design and vehicle handling systems;  in the longer
term it should simplify the design of emergency escape systems.

One safety aspect of a rubber fuel that was mentioned after the briefing:
"Well, if the rocket goes out of control and lands in Los Angeles, it
might not hit anything *on the first bounce*, but ... " :-)

I'm not sure I buy the idea of hybrid rockets myself, but it seems a clever
way to cheaply develop a new rocket, and crazier things have succeeded
with far worse performance tradeoffs.   Hybrids seem more believable
than MSDOS, for example :-)

--
Keith Lofstrom    keithl@loop    tektronix!psueea!qiclab!loop!keithl
Launch Loop, P.O. Box 1538, Portland, Oregon 97207   (503)-628-3645

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

Date: 13 Oct 89 14:53:00 GMT
From: ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu![e-mail]
Subject: Re: Leap Second


[e-mail] (Joe Dellinger) writes:
>Does anyone know if we'll ever get a negative leap second? I know the general
>trend must be for more positive than negative ones being needed. I guess
>when the day lengthens to 24.03 hours or so, we'll have "leap hour parties"
>at the end of every month...

Yes, it is possible that negative leap seconds will be required at
some future time; the slowdown in the Earth's rotation is pretty
irregular.  Here are estimated differences (in minutes) between
Universal Time and Ephemeris Time over the years (data tken from Jan
Meeus, _Astronomical Formulae for Calculators):

Year    UTC-ET      Year    UTC-ET      Year    UTC-ET      Year    UTC-ET
1710    -0.2        1840    0.0        1912    0.2        1971    0.7
1730    -0.1        1870    0.0        1927    0.4        1977    0.8
1750    0        1880    -0.1    1940    0.4
1770    0.1        1895    -0.1    1950    0.5
1800    0.1        1903    0.0        1965    0.6

As you see, things went backwards between 1800 and 1840, and again
between 1870 and 1880.

Kevin

| /         o            Kevin Kenny                             [phone]
|<  /) |  | | |/\        Illini Space Development Society         o  ,    o  ,
| \ X_  \/  | | |        P.O. Box 2255                          40 07 N 88 13 W
[e-mail]        Station A
uunet!uiucdcs!kenny      Champaign, IL 61825                 AD ASTRA PER ARDUA
[e-mail]
[e-mail]

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

Date: 13 Oct 89 16:49:43 GMT
From: thorin!alanine![e-mail]  (Jonathan Leech)
Subject: Re: Titius Series / Quantum orbits?

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>The general equation is:
>
>   R = R0 * b^N
>...
>It seems clear to me that this is not due to chance.

    I think it's not at all surprising that you can choose the free
parameter b to get a good fit.    If you had the *same* b for Uranus,
Jupiter etc., *that* would be noteworthy.
--
    Jon Leech ([e-mail])    __@/
    ``The tuba recital is one of the most memorable experiences of
      music school.''
    - Seen on a bulletin board in the UNC Music School

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

End of SPACE Digest V10 #152
*******************