JAMSAT 日本アマチュア衛星通信協会


Date: Fri, 30 Oct 1998 03:48:48 -0700
From: Chris Lewicki <>
Organization: University of Arizona
To:, amsat-bb@AMSAT.Org
Subject: [jamsat-amsat-bb:20448] SEDSAT Update 10/29

Hi Everyone,
Another (relatively brief) update on SEDSAT.  It appears as from recent data that
SEDSAT has passed the 24 hour mark in uptime -- the latest telemetry I received
(from New Zealand) shows an uptime of 1 Day, 36 minutes.  I haven't received any
reports after this reporting no telemetry, but I assume that it must nearing the
end of its power again, as the battery voltage in that report was 19292mV, and
that's getting down there (18 is gone for sure).  

From telemetry, it appears that it came up right around 8:52:23 UTC on the 29th,
which was just before the 2nd Tucson pass of the night.   If it power cycles
within 25 hours uptime, expect to see it back on the air again sometime after
20:00:00 UTC on 10/30.  This will be good for us in the states, as we'll have a
chance tomorrow evening to test the uplink on several orbits.

For those logging telemetry, thanks!  Keep it coming.  Friday evening I will be
compiling all the data and reports for the week, putting them online, and
developing a good history for the week.  We've figured out that the KISS data
logged from WiSP preserves all the packet information, so that is the best way to
log it.  However, those logging data in ProComm or other terminal programs, those
don't preserve the telemetry data, but they do retain the "uptime" information,
which is valuable on its own.  If you have the ability to, turn on the "MSTAMP"
feature on your TNC, so we can closely correlate uptime and local time.  Make sure
your computer clock is right too :)

Lastly, those anxious for the telemetry standard will get it soon.  I'm
corresponding with Chris Bond on the details, and we want everything to be very
clear in the standard so there is as little confusion as possible. Volunteers
interested in writing a DOS app to decode telemetry can get an advance copy :)	
Also, we hope to get the data in the SEDSAT database server this weekend, and let
people start using that.  A java app which will decode telemetry and potentially
post it to the database will also hopefully be available over the weekend.

That's all for now.

PS - Once the uplink is established, the first priority will be to enable a more
lengthy charging cycle, followed by an imaging session and download -- then the
mode-A antennae will be deployed and we can start to experiment with that! Current
estimates (from memory) are that the satellite will take slightly over 24 hours to
charge up to full capacity while in the "power save" mode. At that level of
charge, the satellite should last for approximately 2.5 days in its current
operating mode (which is what we saw initially over the weekend).  So, what will
likely happen is we will put the satellite in a mode where it doesn't operate for
a day, operate for two, etc...  Anyway, this is all preliminary, but I just wanted
to give everyone an idea of what the possibilities are.

Looks like I was less than brief again, darn!

Christopher A. Lewicki KC7NYV 520.977.0758 Maintainer of SEDS.LPL.Arizona.EDU
     Project Manager, University of Arizona Student Satellite Project
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