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[jamsat-news:1319] * SpaceNews 28-Aug-00 *

* SpaceNews 28-Aug-00 *

BID: $SPC0828


		 	 MONDAY AUGUST 28, 2000

AO-27 suffered a software reset on July 31 while in the southern
hemisphere several minutes before entering an eclipse.  This reset put
the onboard CPU back to the Bootloader software that places the satellite
in "safe mode."  While in safe mode, the transmitters are turned off and
all high level functions are suspended.

This places the satellite in a condition that ground controllers need
to react to.  Normally this means uploading the high level software and
executing it.  It was decided that since the last reset was 6 1/2 years
ago, this reboot might be a single event upset or some other "random"
reboot.  With that in mind, ground controllers downloaded only a small
section of memory and started to upload the high level code.

This was not an easy task.  The primary control station used for uploading
code was not used for over 5 years and required days of work to get back
online.  Once the station was setup for uploading, the code was placed
onboard AO-27.  When the execute command was given, the satellite ran
the high level code for a few seconds, then rebooted.  This may show
that the reboot was not caused by a random act, but it is not conclusive.

Several sections of memory were downloaded from AO-27 and no conclusive
data was found to explain the second reboot.  Ground controller are
looking into several leads.

Jumping to conclusions as to cause are not productive during this process.
It will take controllers time to analyze and determine the cause for the
reboots.  It is unfortunate that during this process, the analog repeater
cannot be used, but the work done now may lead to a longer lifetime of
AO-27.  There is no direct evidence at this time as to cause.  During
the checkout that has been performed so far, controllers have not found
anything onboard to be defective.  This is good news and gives
controllers hope that a recovery is possible.

Facts known about AO-27 as of August 23, 2000:

1) CPU rebooted on July 31, while in TEPR 6, southern hemisphere, in the
   Sun.  This means the batteries did not run down to cause the reboot.
2) TEPR times that were commanded on July 26 where intact and did not
   cause the reboot, i.e. the batteries where charged.
3) The last CPU telemetry frame was recovered and shows battery charge
   state as OK.
4) The code was sampling telemetry at the time of the reboot.
5) Software Uptime was over 6 1/2 years (February 1994).
6) The Amateur Transmitter works at exciter, low, and high power settings.
7) The Amateur Receiver works.
8) The analog repeater works.
9) The Bootloader works.
10) Software uploading/downloading and executing works.
11) Battery voltages are nominal.
12) The 1200 Baud AFSK modulator works.
13) The 1200 Manchester demodulators work.

If you would like to follow AO-27, the exciter on 435.797 MHz is turned on
full time and is running at low power during uploads.  A good tracking beam
setup can hear the exciter if you place your receiver into USB and listen
for the doppler shifting tone.  The satellite is transmitting on every
pass so you can hear it at night as well.

Please keep in mind that all AO-27 ground controllers have full time jobs.
Several have already taken a week of personal vacation from work to spend
time on this problem.  Equipment used in the ground station has been
purchased by the controllers' personal accounts.  This is an all voluntary
crew.  The best help the community can give is to not flood controllers with
e-mail about when is AO-27 going to be back on-line.  They are working as
fast as satellite passes allow.  It takes 3 days of passes to upload code.
Once high level code is running, controllers will need to spend a week of
on-orbit-checkout and gather whole-orbit-data to evaluate the health of
AO-27.  This is needed for continued longevity of this resource.  The
popularity and easy of use to Amateurs getting into satellites is very
well known to everyone involved in recovering AO-27.

The ground controllers have only one request for amateurs: Please do not
transmit on the uplink during passes.  The analog repeater is turned off
so you will not be heard, and you will interfere with the software upload
process if you transmit.

Thank you.

Michael Wyrick
AO-27 Ground Controller

A recent NASA Science News report provided an overview of the Shuttle
Amateur Radio Experiment (SAREX) that has flown on a host of US Space
Shuttle missions in the past.  The report stated that ham radio operators
are notorious for their love of long-distance radio contacts, and that
thanks to NASA's SAREX program, hams and students on Earth have enjoyed
the ultimate long-distance radio experience by contacting astronauts in

The full story is available at:


ISS flight controllers in the United States and Russia continued
preparations this past week for the crew of Shuttle mission STS-106,
who will be the next station visitors.  The mission, aboard shuttle
Atlantis, will open up the newly attached Zvezda living quarters module
for the first time.  The Atlantis crew returned to Houston recently after
spending a week at the Kennedy Space Center preparing for the September
mission to the station.  Atlantis is to deliver several thousand pounds
of equipment, food and supplies to the orbiting outpost to prepare
it for the arrival of the first resident crew in November

Meanwhile, the flight of shuttle Discovery to ISS in October may be
slightly delayed, NASA officials said recently.  The possible delay
is tied to a piece of equipment the shuttle is to deliver to the station
and not to the shuttle itself, which is having no problems.  A decision
on a possible delay will be made shortly.  Discovery is currently scheduled
to lift off October 5th from the Kennedy Space Center.  Its main cargo will
be a station part called a Z-1 truss, which is a framework for holding a
range of station equipment. 

The truss was considered to be ready to head for space after being
inspected by some of the shuttle Discovery crew that is to deliver it.
"Hopefully, we'll light up the night sky for all of you," Discovery's
commander Brian Duffy said after looking closely at the part.  At
19,300 pounds - the U.S. built Z-1 truss will provide a range of
power and heating capabilities for the station.

Following the recent docking of a Progress supply vehicle to the station,
controllers pressurized the vestibule between Progress and Zvezda and
conducted a successful check for leaks.  The seven-member crew of
STS-106 will unload supplies and equipment from the Progress into
the station through the vestibule.

A successful test firing of thrusters on the Progress craft was also
performed and changed the velocity of the station by about 2-miles per hour
(one meter per second).  A second firing again changed the velocity and
one or two more firings may be performed to fine-tune the station's position
for the rendezvous with STS-106. 

With the docking of Zvezda, the next phase in the development and
installation of the ham radio gear on ISS is the launch and installation
of the Initial, Phase 1 Amateur Radio station.  This is currently
scheduled to occur on STS-106.

The initial station will include 2-meter and 70-cm handheld transceivers,
TNC, a specially developed headset, signal adapter module, and specially
developed power adapters and the interconnecting cabling.  The antenna
systems that the Italian/Russian/US team have developed for the
Service Module are ready but cannot be installed until later next year.
In the meantime, the ARISS international team has received permission
to use the Zarya antennas on 2-meters.

This is an exciting time for Amateur Radio and the International Space

[Info via the AMSAT-NA News Service]

Comments and input for SpaceNews should be directed to the editor
(John, KD2BD) via any of the paths listed below:
WWW:        http://www.njin.net/~magliaco/
MAIL:       John A. Magliacane, KD2BD
            Department of Engineering and Technology
            Brookdale Community College
            765 Newman Springs Road
            Lincroft, New Jersey 07738
INTERNET:   kd2bd@amsat.org, magliaco@email.njin.net

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