Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_2/V16NO298.TXT

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Date: Wed, 10 Mar 93 05:06:44
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #298
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 10 Mar 93       Volume 16 : Issue 298

Today's Topics:
                 20 kHz Power Supplies "blowing up"!
                         Acceleration of ice
            Anyone interested in being a consultant (read)
                           latest manifest
                         Lunar Ice Transport
         Minimal Manned Capsule paper online now... (2 msgs)
                        Mir visible UK/Ireland
                           PFF Instruments
               Proposed Jupiter f/c/b mission (3 msgs)
                      Rocket Propulsion (3 msgs)
                              Starprobe
                          Will Huygens Float

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: 9 Mar 1993 23:23 CST
From: [e-mail]
Subject: 20 kHz Power Supplies "blowing up"!
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Pat) writes...
>In article <[e-mail]> [e-mail] (David B. Mckissock) writes:
>>In article <[e-mail]>, [e-mail]

[various rantings deleted]

>Basic engineering criteria and design decisions were made for SSF
>on fatally flawed reasoning.  all the paper in the world won't
>make up for those mistakes.
>
>I dare you to justify 3 things:
>
>    1)  20 KHz power developement.
>

Since I started this and you have jumped on it like a bulldog I will answer
you. The primary advantage of 20 khz is light weight and some ease of
integration of the entire system in orbit. It has several disadvantages
that were conclusively shown in 1988 and 1989. There never was a lot of money
spent on the idea. It was a brainchild of the Lewis folks who were given the
task of coming up with the requirements for WP IV. Since Marshall already had
a power system in place that was a 75KVA demonstrator based upon an
incremental upgrade of Skylab, the boys at Lewis simply wanted to explore
if technologically, there was a better solution.  It turns out that there
was no better method and still today that is true. The issue was
settled years ago and nothing bad came of it.

You are the one pat that is always pushing technology, but when someone
does that then you get upset. And don't say that anyone that has common sense
could see that 20khz would not work. It was a good idea to try even if it
did lead to a dead end.

>    2)  Non Metric (english)  component selection with the
>    european modules being Metric.
>

So what. Read a Japanese technical manual. They quote everything in metric
but if you do the conversions they are english standard. Who cares if
the english system takes a little math to do the work. Metric is good
but we have had the technology for conversions for a hundred years now and
it is well understood.

>    3)  Total failure to practice EVA until this year.
>

I guess you never saw many missions before Challenger. They blew it by going
off the other end and being too conservative. Well with the Intelsat rescue
that changed so what is your problem?

Me thinks you like to complain too much

Dennis University of Alabama in Huntsville

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

Date: Wed, 10 Mar 1993 06:56:31 GMT
From: David Bromage <[e-mail]>
Subject: Acceleration of ice
Newsgroups: sci.chem,sci.engr.chem,sci.space,sci.physics

Daniel Seeman ([e-mail]) wrote:
>Hi,

>I have no answers, but a comment.  Aren't there ice crystals in the trailing
>stream of a commet?  I don't know how fast they are traveling, or if they
>just appear in the trailing stream because of some condensation process (I
>doubt it, though).  But you may want to research this for some additional
>insights...

The tail of a comet is quite a complex mixture of gases. A comet is made
mostly of ice, with a bit of methane, ammonia and carbon monoxide and a
bit of dust and rock. As early as 1868 the astronomer William Huggins found
common features between the spectrum of a comet's tail and natural gas
("olefiant' gas). He also identified organic matter in comets and later
cyanogen was found.

What you see as the tail is a stream of gases being released from the
comet as it is warmed by the solar wind. The tail does not flow in the
opposite direction to the comet's motion but points away from the sun.
It is also possible that the gases may glow as an aurora does, but I'm not
100% sure of that.

If anyone can add to this, please do.

David Bromage

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

Date: Wed, 10 Mar 1993 03:39:27 GMT
From: terence robert slywka <[e-mail]>
Subject: Anyone interested in being a consultant (read)
Newsgroups: sci.space,sci.optics,sci.electronics,sci.aeronautics

Do you have a skill or specialized knowledge to offer the
marketplace?  Are you interested in short-term projects that
demand your specific skill?  Are you interested in evening/weekend
work-at-home for local, national and international companies while
keeping your present job?  If you answer 'yes' to any or all of these
questions you can not afford to miss this opportunity.

If you are interested in working for large and small businesses as a
consultant contact me directly at the addresses listed below and I will
send you additional information by regular mail.

TSLYWKA@IUBACS
[e-mail]

Respectfully,

Terence Slywka

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

Date: 10 Mar 93 06:29:00 GMT
From: [e-mail]
Subject: latest manifest
Newsgroups: sci.space

Can someone email me the very latest shuttle manifest please?

-Tony Ryan, "Astronomy & Space", new International magazine, available from:
Astronomy International, P.O.Box 2888, Dublin 1, Ireland.
6 issues (one year sub.): UK 10.00 pounds, US$20.00 (surface, add US$8.00).
ACCESS/VISA/MASTERCARD accepted (give number, expiry date, name&address).
Newslines (48p/36p per min):    0891-88-1950 (UK/NI)    1550-111-442 (Eire).

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

Date: Wed, 10 Mar 1993 04:46:25 GMT
From: Henry Spencer <[e-mail]>
Subject: Lunar Ice Transport
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Ross  Borden) writes:
>    To maintain high through-put, a continuous stream of vehicles
>would haul ice from the polar ice mines to the equatorial processing
>plants...

Surely it's a whole lot simpler to put the processing plants at the
poles too.  (For one thing, at the poles all they need is a tall tower
to get continuous solar power.)

>And are there lunar maps with sufficient resolutions to chart a route?

The lunar map situation is, roughly speaking, incredibly poor.  We have
much better maps of Mars than of the Moon.  The situation should improve
substantially with the Clementine 1 mission next year.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: 10 Mar 1993 06:36:52 GMT
From: George William Herbert <[e-mail]>
Subject: Minimal Manned Capsule paper online now...
Newsgroups: sci.space

    After several requests, I've put an ASCII format
version of my 1991 paper on Minimal Manned Capsules
and the current 1993 commentary on it (including where
I went wrong to start and the changes to the vehicle
concept since 1991).
    They're available at the ftp site ocf.berkeley.edu
login anonymous
directory pub/Space
files mmc.91paper and mmc.91commentary

    They may be uploaded to the International Space Universoty
FTP server (info.isunet.edu) at some point, though that is waiting
on my doing some other projects at ISU.

    Please keep in mind that I was still an undergrad student
at the time the inital paper was written, and in some ways
it shows it (in addition to just the major technical problem
of having underestimated heatshield mass the first time).
It's a professional paper, but not a matured professional paper 8-)

-george william herbert
Retro Aerospace
[e-mail]
[e-mail]
[e-mail]

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

Date: 10 Mar 93 06:36:10 GMT
From: George William Herbert <[e-mail]>
Subject: Minimal Manned Capsule paper online now...
Newsgroups: sci.space

    After several requests, I've put an ASCII format
version of my 1991 paper on Minimal Manned Capsules
and the current 1993 commentary on it (including where
I went wrong to start and the changes to the vehicle
concept since 1991).
    They're available at the ftp site ocf.berkeley.edu
login anonymous
directory pub/Space
files mmc.91paper and mmc.91commentary

    They may be uploaded to the International Space Universoty
FTP server (info.isunet.edu) at some point, though that is waiting
on my doing some other projects at ISU.

    Please keep in mind that I was still an undergrad student
at the time the inital paper was written, and in some ways
it shows it (in addition to just the major technical problem
of having underestimated heatshield mass the first time).
It's a professional paper, but not a matured professional paper 8-)

-george william herbert
Retro Aerospace
[e-mail]
[e-mail]
[e-mail]

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

Date: Wed, 10 Mar 1993 06:41:08 GMT
From: [e-mail]
Subject: Mir visible UK/Ireland
Newsgroups: sci.space,sci.astro

If anyone in UK/Ireland watches out for Mir please post your latitude,
longitude, height above sea-level and UT when you see Mir pass above or
below any convenient bright star.

You can get latest prediction of when to look from newslines below:


-Tony Ryan, "Astronomy & Space", new International magazine, available from:
Astronomy International, P.O.Box 2888, Dublin 1, Ireland.
6 issues (one year sub.): UK 10.00 pounds, US$20.00 (surface, add US$8.00).
ACCESS/VISA/MASTERCARD accepted (give number, expiry date, name&address).
Newslines (48p/36p per min):    0891-88-1950 (UK/NI)    1550-111-442 (Eire).

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

Date: Wed, 10 Mar 1993 03:36:04 GMT
From: Dave Tholen <[e-mail]>
Subject: PFF Instruments
Newsgroups: sci.space

Steve Derry writes:

> Since there will be two PFF spacecraft, would it make sense for the two to
> carry slightly different science payloads?  For example, the second spacecraft
> could carry a magnetometer in place of the UV spectrometer.
>
> This would allow a broader science return while remaining within mass and
> power constraints (although program costs and risk would increase slightly).

It's been discussed, but as you can imagine, different payloads mean different
designs, which all translates into higher costs.  This is not meant to say
that it won't be done.  If it can be done within the cost constraints, and if
it is determined to be sufficiently valuable, then I suspect that the OPSWG
will endorse the idea.

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

Date: 10 Mar 1993 02:26:41 GMT
From: James Ashton <[e-mail]>
Subject: Proposed Jupiter f/c/b mission
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Ron Baalke) writes:
> In article <[e-mail]>, [e-mail] (Henry Spencer) writes...
> >In article <[e-mail]> [e-mail] ("Phil G. Fraering") writes:
> >>Earth-moon or earth-sun lagrange point?
> >>
> >>It looks like you're talking about the earth-sun L1 point, but
> >>isn't that a little far?
> >
> >Sounded to me like Earth-Sun, and it's only about 1.5 million km away.
> >A halo orbit around the Earth-Sun L1 is a good place to park something
> >that wants to be well away from Earth and in continuous sunlight.
>
> That is exactly where the Soho spacecraft will be placed, in halo orbit
> around the Earth-Sun L1 point.  It is due to be launched in 1995.

What do you mean by a halo orbit?  I'm aware that trojan asteroids
orbit L4 and L5 points but my understanding was that no other L points
were stable.  I thought that there was a (small) gravity well around L4
and L5 but that L1, L2 and L3 all had gravity humps (or maybe saddle

points) so that you'd need to be exactly on the point to avoid
disturbing forces.
--
James Ashton                          System Administrator
VK2ZJA                         Department of Systems Engineering
Voice [phone]      Research School of Physical Sciences and Engineering
FAX   [phone]                Australian National University
Email [e-mail]               Canberra ACT 0200 Australia

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

Date: Wed, 10 Mar 1993 04:50:40 GMT
From: Henry Spencer <[e-mail]>
Subject: Proposed Jupiter f/c/b mission
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>RB| That is exactly where the Soho spacecraft will be placed, in halo orbit
>RB| around the Earth-Sun L1 point...
>
>I *think* that the L1 "point" is large enough for several spacecraft to
>stay there at a time.  It _is_ one of the astable Lagrange points, so
>stationkeeping will be necessary to hold it there lest it drift off.

At the L1 point itself you might worry a bit about collisions, although
it's still pretty unlikely.  However, these craft will be in halo orbit
around the L1 point, not at the point itself.  Putting them 180 degrees
away from each other in the halo orbit will suffice to keep them hundreds
of thousands of km apart.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Wed, 10 Mar 1993 04:56:29 GMT
From: Henry Spencer <[e-mail]>
Subject: Proposed Jupiter f/c/b mission
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (James Ashton) writes:
>What do you mean by a halo orbit? ...

The L1 point is on the Earth-Sun axis.  It's not terribly stable.  But
an "orbit" *around* the axis, near the L1 point, is almost stable, to
the point where ISEE-3 spent several years in one and used only a few
kilograms of fuel.  That's not much worse than Clarke orbit.

A halo orbit is actually a complex solar orbit, of course, but looking
at it from the Earth, it looks like the spacecraft is orbiting around
the Earth-Sun axis.  To see why it's called "halo orbit", note that you
can do it around the L2 point as well... and if you do it around the
Earth-Moon L2 point, then as viewed from the Earth the orbit looks like
a halo around the Moon.  (Such an orbit is a good place to put a comsat
for operations on the lunar farside, since it has a good view of the
farside and is far enough from the Earth-Moon axis to be visible from
the Earth.)
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Tue, 9 Mar 1993 06:29:47 GMT
From: Gibson Lam <[e-mail]>
Subject: Rocket Propulsion
Newsgroups: sci.space

    I am a student doing a research project on Goddard, the man who first
invented rocket propulsion.  Of all the eventual uses that rocket
propulsion made possible, such as war missiles or the space shuttle, does
anyone think that Goddard should be responsible for the eventual uses of
his invention?  I would also appretiate any information that you could
give me on Goddard or rocket propulsion.

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

Date: 10 Mar 1993 05:31:11 GMT
From: Tim Thompson <[e-mail]>
Subject: Rocket Propulsion
Newsgroups: sci.space

In article [e-mail], [e-mail] (Gibson Lam) writes:
>     I am a student doing a research project on Goddard, the man who first
> invented rocket propulsion.  Of all the eventual uses that rocket
> propulsion made possible, such as war missiles or the space shuttle, does
> anyone think that Goddard should be responsible for the eventual uses of
> his invention?  I would also appretiate any information that you could
> give me on Goddard or rocket propulsion.

   Do you mean by "responsible", something like "since rockets were made into
weapons of war, It's all Goddard's fault". Or perhaps "Thank Goddard for space
flight"? No, I don't think Goddard should be responsible. With precious few
exceptions, how can any inventor anticipate the use/misuse to which his/her
inventions will be put?

---
ALL OPINIONS ARE MINE! ALL MINE !!!! HOWEVER, YOU ARE WELCOME TO SHARE THEM.
------------------------------------------------------------
Timothy J. Thompson, Earth and Space Sciences Division, JPL.
Assistant Administrator, Division Science Computing Network.
Secretary, Los Angeles Astronomical Society.
Member, BOD, Mount Wilson Observatory Association.

INTERnet/BITnet:    [e-mail]
NSI/DECnet:         jplsc8::tim
SCREAMnet:          YO!! TIM!!
GPSnet:             118:10:22.85 W by 34:11:58.27 N

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

Date: Wed, 10 Mar 1993 06:52:05 GMT
From: James R Ebright <[e-mail]>
Subject: Rocket Propulsion
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gibson Lam) writes:
>    I am a student doing a research project on Goddard, the man who first
>invented rocket propulsion.  Of all the eventual uses that rocket
>propulsion made possible, such as war missiles or the space shuttle, does
>anyone think that Goddard should be responsible for the eventual uses of
>his invention?

As Tom Lehrer once said, "'Once zee rockets are, who cares where zay
come down.  Zat's not my department' said Werner VonBraun". ;-)

Actually, Goddard's work was pretty far removed from the present uses.
Putting the blame on him is almost like blaming Shockley for the computer
and it's uses.  But not everyone can make this defense.  VonBraun for
example.

Goddard, being an American, is often cited by Americans as the father
of modern rocketry.  But I remember reading somewhere that some of
the German scientists debriefed at the end of WWII had never heard of
his work...  Sometimes the level of technology is just 'ripe' and if
one person doesn't do it, someone else soon will.
--
        Jim Ebright ([e-mail])
                Lbhe zbgure zngrf bhg bs frnfba :-)
    Fax # [phone].  Tel # [phone].  Beeper # 614-646-1093
     >>>    All kids can be educated -- even yours and mine.    <<<

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

Date: 09 Mar 93 22:39:51 GMT
From: Alex Howerton <[e-mail]>
Subject: Starprobe
Newsgroups: sci.space

>>Of course, in order to kill its angular momentum enough
>>to get that close to the sun, it may make use of Jupiter for a gravity assist
>>(as Ulysses did to get kicked out of the ecliptic plane), at which distance
I've got a question that also applies to an earlier discussion about shooting
nuclear waste into the sun. If you launched a craft into transfer orbit, then
shoot it in the exact opposite direction of Earth's revolution, would that
kill the angular momentum?
-signed, physics-impaired in Seattle
>>it'd need RTG's anyway.

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

Date: Wed, 10 Mar 1993 04:48:40 GMT
From: Henry Spencer <[e-mail]>
Subject: Will Huygens Float
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Kevin W. Plaxco) writes:
>...  With regard to the
>camera ... what are postulated light levels?

Don't get your hopes for images *too* high; the system is an atmosphere
instrument that does imaging as a sideline, not an optimized imager.
Still, it's better than no camera at all...
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

End of Space Digest Volume 16 : Issue 298
------------------------------