Date: Wed, 1 Dec 93 04:30:33 PST
From: Ham-Space Mailing List and Newsgroup <ham-space@ucsd.edu>
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Subject: Ham-Space Digest V93 #96
To: Ham-Space
Ham-Space Digest Wed, 1 Dec 93 Volume 93 : Issue 96
Today's Topics:
APT-Satellites: Report NOV 28, 1993
Building PC Based Satellite Station
Control of Amateur Satellites
EJASA: SETI Information Source
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----------------------------------------------------------------------
Date: Mon, 29 Nov 1993 08:45:06 GMT
From: ucsnews!sol.ctr.columbia.edu!xlink.net!gmd.de!peter.henne%gmd.de@network.ucsd.edu
Subject: APT-Satellites: Report NOV 28, 1993
To: ham-space@ucsd.edu
Observed at station 50.7 NLat, 7.1 ELon, NOV 28, 1993
NOAA-9: APT 137.62 On
NOAA-10: APT 137.50 On
NOAA-11: APT 137.62 On
NOAA-12: APT 137.50 On
Meteor 2-21: APT 137.85 On
Meteor 3-3: APT 137.30 On
Now all NOAA's switch from ch.2 (vis) to ch.3 (IR) when
approaching night-parts of their orbits. The Meteor's transmit
only vis from illuminated parts, as the descending passes are
more and more earlier at morning (exspecially weak Meteor 2-21)
they will become somewhat useless for stations above 40 deg
northern Latitude. Hoping for Meteor 3-6, tentative launch-date
NOV 29 (info from Mike Kenny, Bureau of Meteorology, Australia).
+------------------------------------------+
|Peter Henne (peter.henne@gmd.de) |
| (henne@gmd.de) |
|German Nat.Research Center.f.Comp.Science |
|D-5205 St.AUGUSTIN 1 |
|Fed.Rep. of Germany |
+------------------------------------------+
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Date: 29 Nov 1993 02:57:22 GMT
From: mvb.saic.com!unogate!news.service.uci.edu!usc!howland.reston.ans.net!gatech!usenet.ufl.edu!usenet.cis.ufl.edu!thanos@network.ucsd.edu
Subject: Building PC Based Satellite Station
To: ham-space@ucsd.edu
I would like to build a PC based weather satellite station.
I would appreciate it if anyone out there provides info on
schematics, resources, requirements, etc. I am just starting so I could
use any help I can get.
I appreciate any help,
Thanos Karras
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Date: 28 Nov 1993 23:12:16 -0800
From: swrinde!sgiblab!darwin.sura.net!howland.reston.ans.net!vixen.cso.uiuc.edu!qualcomm.com!qualcomm.com!not-for-mail@network.ucsd.edu
Subject: Control of Amateur Satellites
To: ham-space@ucsd.edu
In article <2d0g59$429@reznor.larc.nasa.gov>,
Steve Derry <s.d.derry@larc.nasa.gov> wrote:
>For those of you who design, build, and operate amateur radio satellites --
>What do you use for attitude control and knowledge?
For attitude determination, almost all have used sun and earth sensors.
The UoSat series, built at U. of Surrey, have used flux-gate magnetometers.
P3D, now under design, and the most ambitious amateur satellite to date,
is planned to use GPS for attitude determination.
Several different methods of attitude control have been used.
Oscar-10 and Oscar-13 (highly elliptical orbits) use magnetorquers.
UoSat series has used a gravity gradient boom and magnetorquers.
AMSAT's microsat series uses 4 permanent magnets in the spacecraft body
to allign the spacecraft with the earth's magnetic field. A solar propeller
(antenna blades painted white on one side and black on the other) spin the
spacecraft (for thermal control), and finally hysteresis damping rods
limit spin rate, and reduce oscillations. Note these spacecraft are in
nearly polar orbits, so the magnets cause them to flip twice during each
orbit.
P3D is planned to use momentum wheels.
>Is attitude control even necessary for small satellites?
Depends on what you're trying to do. If you're in a very low orbit, and
use nearly omnidirectional antennas, for example, you care a lot less
about attitude than if you're in a near-Molniya (highly elliptical) orbit,
using high-gain antennas to allow low-power users on the earth to communicate
while satellite is near apogee. Amateur radio satellites have covered all
these cases.
>Also, is thermal control strictly passive, or are there heaters on board
>your spacecraft?
Passive. (At least I don't know of any that have heaters. So many
amateur spacecraft have been built, in so many countries, that it's quite
possible that somebody threw in a heater and didn't tell me. :-> )
> Thanks!
For more information, may I suggest you joint AMSAT, the non-profit group
that builds and launches these puppies. There is an AMSAT organization in
most major countries. In the US, call 301-589-6062.
A handy reference that lists summary information about many of the amateur
spacecraft is: The Satellite Experimenter's Handbook, by Martin Davidoff,
published by The American Radio Relay League, Inc, ISBN 0-87259-004-6.
I believe you can buy a copy from AMSAT. 2nd edition was published in 1990,
so it's a couple of years out of date, and doesn't list the last crop of
amateur sats, but it's an excellent starting place.
------------------------------
Date: 29 NOV 93 18:01:30 EST
From: pa.dec.com!nntpd.lkg.dec.com!verga.enet.dec.com!klaes@decwrl.dec.com
Subject: EJASA: SETI Information Source
To: ham-space@ucsd.edu
EJASA: SETI Information Source
I am Larry Klaes, Editor of the Electronic Journal of the
Astronomical Society of the Atlantic (EJASA), a position I have
held since the founding of the EJASA in August of 1989.
The EJASA is published by the Astronomical Society of the
Atlantic, Incorporated. The ASA is a non-profit organization
dedicated to the advancement of amateur and professional astronomy
and space exploration, as well as the social and educational needs
of its members. The EJASA is a place for those on the Internet to
publish their works on the field. The EJASA is published monthly
and posted on the USENET astronomy and space newsgroups.
Numerous articles in the EJASA have been devoted to SETI and
its related fields. Included among them is the original six-part
paper by Dr. Stuart Kingsley of Columbus, Ohio on his work with
Optical SETI in the January 1992 issue. Dr. Kingsley was profiled
in the Summer 1993 issue of The Planetary Society's Bioastronomy
News publication and spoke at the recent Bioastronomy Conference
in Santa Cruz, CA.
Robert Dixon, head of Earth's longest-running SETI program
located at Ohio State University, contributed an article on the
project's history in the June 1992 issue of the EJASA.
The December issue will feature a SETI article by Guillermo A.
Lemarchand from the University of Buenos Aires, Argentina.
The complete list of current SETI articles in the EJASA follows
this paragraph. All are available either from me or the ASA anonymous
FTP site at chara.gsu.edu (131.96.5.29).
"Does Extraterrestrial Life Exist?", by Angie Feazel - November 1989
"Suggestions for an Intragalactic Information Exchange System",
by Lars W. Holm - November 1989
"Radio Astronomy: A Historical Perspective", by David J. Babulski
- February 1990
"Getting Started in Amateur Radio Astronomy", by Jeffrey M. Lichtman
- February 1990
"A Comparison of Optical and Radio Astronomy", by David J. Babulski
- June 1990
"The Search for Extraterrestrial Intelligence (SETI) in the Optical
Spectrum, Parts A-F", by Dr. Stuart A. Kingsley - January 1992
"History of the Ohio SETI Program", by Robert S. Dixon - June 1992
"New Ears on the Sky: The NASA SETI Microwave Observing Project",
by Bob Arnold, the ARC, and JPL SETI Project - July 1992
"First International Conference on Optical SETI", by Dr. Stuart A.
Kingsley - October 1992
"Conference Preview: The Search for Extraterrestrial Intelligence
(SETI) in the Optical Spectrum", by Dr. Stuart A. Kingsley
- January 1993
I will make available upon request the complete list of EJASA
back issues. I will be glad to send on-line copies of any issues
to those who wish to see them. Readers are also welcome to submit
papers on astronomy and space exploration for publication in the
EJASA.
Regards,
Larry Klaes klaes@verga.enet.dec.com
or - ...!decwrl!verga.enet.dec.com!klaes
or - klaes%verga.dec@decwrl.enet.dec.com
or - klaes%verga.enet.dec.com@uunet.uu.net
EJASA Editor, Astronomical Society of the Atlantic
"When we try to pick out anything by itself, we find it
hitched to everything else in the Universe." - John Muir
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End of Ham-Space Digest V93 #96
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