From: dave@ips.oz.au (Dave Horsfall)
Subject: * SpaceNews 28-Sep-92 *
Organization: IPS Radio and Space Services.  Sydney, Australia.
Distribution: aus
Date: Mon, 28 Sep 1992 07:45:53 GMT

Bulletin ID: $SPC0928


                              =========
                              SpaceNews
                              =========


                      MONDAY SEPTEMBER 28, 1992


SpaceNews originates at KD2BD in Wall Township, New Jersey, USA.  It
is published every week and is made available for unlimited distribution.


* NEW MICROSAT FOR 1992 *
=========================
A new Microsat-class OSCAR satellite is planned for launch before the
end of 1992.  UNAMSAT-1, the first Mexican Amateur satellite is being
constructed at UNAM, the Autonomuous University of Mexico.  As with
the earlier Microsats it will have five modules, each about 20 cm
on a side.  Four of the five modules are updated clones of existing
Microsat hardware/software:

 - Dual 70cm PSK transmitters (design by YT3MV)
 - V40 CPU (designed by WA7GXD and others from TAPR, with
     modifications by I2KBD and ITAMSAT)
 - Power system with BCR (by KE3Z/ARRL) and batteries
 - 5-channel 2-meter FSK receiver (by W3IWI)
 -   Similar software to other Microsats (by NK6K and G0/K8KA)
 - AART Bus architecture (by W3IWI and N5BRG)

The main differences from the earlier Microsat configuration are:

 - The V40 CPU will have 4 MB of bulk RAM (vs. 8 MB).
 - UNAMSAT-1 will be equipped with Gallium Arsenide solar panels
    (vs. the BSFR technology flown on the Microsats).

The innovative new addition in UNAMSAT-1 is the brand new on-board
experiment in the 5th "TSFR" ("This Space For Rent") module.
UNAMSAT-1 will act as a meteor sounder.  It will contain a 40.097 MHz
transmitter with 60 watts output during pulses from which can be varied
from 1 to 10 msec in duration and with a pulse repetition rate of 1
to 10 seconds, as controlled by a 68HC05 CPU.  The meteor echoes will
be detected on a receiver at the same frequency designed to detect the
returned echo and measure its doppler shift.  The use of the meteor
sounder is to obtain research data on the full-sky spatial and velocity
distribution of meteors, with the focus on a search for high-velocity
meteors originating outside our solar system.

The 41 MHz frequency for this transmitter is in the accordance with the
ITU frequency allocations table for scientific  research and both the 41
MHz and amateur frequencies have been licensed by Mexican authorities.
The transmitter has a crystal frequency controlled exciter and a class
"E" power amplifier.

The meteor receiver is an SSB "zero-IF" design (suggested by W3IWI) and
the return echoes are digitized and stored in the normal V40 Microsat
computer's RAM.  After each pulse, the spectrum of the received signal
will be determined using the onboard V40 as a DSP Fourier Transform
spectrum analyzer.  If a meteor echo is detected, the echo will be saved
for later transmission as a special telemetry frame.

The 1-10 second repetition rate for the meteor transmitter will be
adjusted depending on the state of charge of the batteries and other
spacecraft power requirements, and also on the time domain requirements
of the echoes.

Detailed telemetry formats for meteor "radar" are still being defined.
Data will be sent using standard amateur AX.25 packet specifications.

When UNAMSAT-1 is not involved in meteor research, it can be turned into
a standard PACSAT message store-and-forward satellite.

Also still to be finalized are the detailed 2-meter uplink and 70-cm
downlink amateur frequencies.

XE1TU has been responsible for technical development of UNAMSAT-1 along
with the team of hams and students at the University.  The hams are
XE1MGI, XE1XUS, XE1YLS in Mexico City.  Scientific direction for the
project has been provided by UNAM Professor of Astronomy Arcadio Poveda.
AMSAT-NA provided technical details of its Microsat satellites to UNAM.
During the development  of UNAMSAT-1, technical assistance from AMSAT-NA
has been provided by W3GEY, N4HY, NK6K, W3IWI and WD4FAB.  ITAMSAT
assistance was coordinated through I2KBD.

The UNAMSAT-1 launch will also be the beginning of a new era.  Along with
a larger meterological satellite, it will be launched by the Russian Space
Agency and by the Russian Academy of Sciences on a decommissioned SS-18
ICBM into an orbit about 1000 km high.  At this time the launch is
scheduled for the first week in December, 1992.  Details for the launch
are being worked out at the present and will be made available as soon
as possible.

[Info via W3IWI]


* SHUTTLE O-RING PROBLEM *
==========================
For the first time since the Challenger disaster in 1986,
NASA has found a leaking O-ring seal on a solid rocket
booster being readied for shuttle launch.
The leak was discovered last week during a test on motors
intended for Discovery's liftoff in November, the space
agency said Tuesday in Cape Canaveral, Florida.

A failure in such a rubber seal was responsible for the 1986
explosion that destroyed Challenger shortly after takeoff,
killing the seven astronauts aboard. Since then, the seal has
been redesigned and an extra O-ring added. Orings seal off
joints in the boosters.

The right booster will be taken apart and given new O-rings,
and should be reassembled by the end of next week, said NASA
project engineer Philip Weber. Officials said they did not
know if the leak would affect the launch.

[Info taken from LI Newsday 24-Sep-92 and supplied by N2JUX]


* FO-20 NEWS *
==============
Mode JA transponder operation is scheduled from September 30th at 01:55 UTC
through October 1st at 02:23 UTC.

[Info via Kazu Sakamoto, JJ1WTK]


* MESSAGES *
============
Thanks to the following who sent feedback to SpaceNews, especially:

KB1ZK  N1MDZ  VE1DJB  VE2BOG


* FEEDBACK/INPUT WELCOMED *
===========================
Mail to SpaceNews should be directed to the editor (John, KD2BD) via any
of the following paths:

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INTERNET : kd2bd@ka2qhd.de.com  -or- kd2bd@amsat.org

MAIL     : John A. Magliacane, KD2BD
           Department of Engineering and Technology
           Advanced Technology Center
           Brookdale Community College
           Lincroft, New Jersey  07738
           U.S.A.


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-- 
Dave Horsfall (VK2KFU)         VK2KFU @ VK2RWI.NSW.AUS.OC
dave@ips.OZ.AU                  ...munnari!ips.OZ.AU!dave