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[jamsat-news:480] * SpaceNews 20-Jan-96 *
SB NEWS @ AMSAT $SPC0120
* SpaceNews 20-Jan-97 *
BID: $SPC0120
=========
SpaceNews
=========
MONDAY JANUARY 20, 1997
SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It
is published every week and is made available for non-commercial use.
* OSCAR-11 NEWS *
=================
During the last month (18 December - 14 January) good, steady signals
have been received from OSCAR-11 on 145.826 MHz. No further reports
of Mode-S reception after 12 December have been received, although
Ken G8VR did listen on 2401.5 MHz during the last week of December,
but nothing was heard. By way of comparison, he was able to receive
good signals from DOVE.
As briefly reported last month, in mid December the spin period, as
shown in the status blocks, increased from the usual value of about
360 to +939 seconds. This indicated that the speed of rotation
had decreased, and that the satellite was rotating in the opposite
direction to normal. On one pass the -Y axis facet temperature had
risen to 56.6 deg. C, and +Y fallen to -16 deg. C. Temperatures
like these were frequently seen several years ago, but not recently.
The ground controllers quickly discovered that the Y-axis magnetorquer
had failed. They manually activated the magnetorquer coil which is
controlled by a relay, but could only detect a small change in line
current, due to the relay coil. This indicated that the relay contacts
had failed, or that the Y-axis magnetorquer coil was open circuit.
By changing the diary software, the alternative X-axis magnetorquer
was selected. This restored the spin rate, direction, and facet
temperatures to normal.
At about the same time as the spin problem occurred, the internal
temperatures started to fall. At first it was assumed that it was
connected with the spin problem, however the temperatures have
continued to fall. On one early morning pass the solar array current
was zero, and the battery was discharging. It was later discovered
that the pattern of solar eclipses that has been repeated during the
last few years, had changed. Eclipses had already started, and would
continue throughout 1997. Preliminary calculations for 1997 indicate
that the sunlight level would fall to 72% by mid June, and then increase
to 87% by November and then start falling again (100% is full sunlight).
Several WOD surveys of channels 1, 2, 3, 61, (magnetometers) have been
taken, and the current one is dated 02-January-97. These showed the spin,
before and after corrective action by ground control. The frequency of
the sinusoidal variations of the X and Y axes shows the rotational rate
of the satellite (spin), and the relative phase of the X and Y measurements
indicates the direction of rotation. During the 16:04 UTC pass over UK
on 03 January, binary WOD was received on 435 MHz and continued on 145 MHz.
Almost a complete WOD of the current survey was received on a single pass.
The contents of this WOD file are available on the World Wide Web (see
below).
Two AMSAT bulletins by Richard G3RWL have been uploaded to OSCAR-11.
Topics have included the P3D launch, OSCAR-11 status, magnetorquer
failure, and honors for Prof. Martin Sweeting G3YJO. Bulletins
always include the latest Keplers for OSCAR-11 in AMSAT format.
The operating schedule is unchanged.
ASCII status (210 seconds)
ASCII bulletin (60 seconds)
BINARY SEU (30 seconds)
ASCII TLM (90 seconds)
ASCII WOD (120 seconds)
ASCII bulletin (60 seconds)
BINARY ENG (30 seconds)
There are also additional status blocks after each bulletin is transmitted,
and between ASCII TLM and WOD.
The Mode-S beacon is ON, but telemetry indicates that it has partially
failed, and delivering half power. Any reports of reception on 2401 MHz
would be most welcome and should be directed to: g3cwv@amsat.org.
The 435.035 MHz beacon is normally OFF, but can sometimes be heard when
the satellite is being commanded by ground control, ie: within range of
Guildford, UK. Likely times are between 1500 and 1800 UTC, Fridays or
at weekends. When the 435 beacon is transmitting, the 145 MHz beacon
is normally OFF. The data transmitted is mainly binary.
Clive Wallis has uploaded some more OSCAR-11 files to the World Wide Web.
The aim is to include data files, especially WOD, decoding software,
information files, and the current status report. Most of the content
will be zipped up into convenient packages, so that the text can be
viewed off-line. Please note that the contents are based on what Clive
has received from the satellite, and other sources. Any opinions
expressed are those of Clive, and not necessarily those of the UoS
ground controllers.
The URL is http://www.users.zetnet.co.uk/clivew/
[Info via Clive, G3CWV]
* RS-16 NEWS *
==============
There may very well be a new RS (Radio Sputnik) Amateur Radio satellite
on the horizon soon. Richard W. L. Limebear, G3RWL, provided the following
report on RS-16 that was posted on the UO-22 satellite by Leo, UA3CR:
Period = 95 min
Inclination = 97.2 deg.
Uplink = 145.915 - 145.948 MHz
Downlink = 29.415 - 29.448 MHz
Beacons = 29.408 , 29.451 MHz
Pwr 29 MHz Down = 1.2 W /4 W
Beacon 1 = 435.504 MHz
Beacon 2 = 435.548 MHz
Pwr 435 MHz Beacons - 1.6 W
Launch - ??-Jan-97 / ??-Feb-97
G3RWL speculates that it might be interesting to listen between the two
70-cm beacons to see if there's a transponder downlink there. Likewise
with ROBOTS. Places to try for an uplink *might* be a) 40 kHz LF of uplink
passband, or b) somewhere around 145.830/840 MHz. Strange, though, about
a year ago they released the information that the next RS would have a
store-and-forward capability.
[Info via Richard W. L. Limebear, G3RWL]
* MISSION MIR 97 *
==================
During the time period February 4th through 24th, an aditional German/Russian
space mission is sheduled. German astronaut Dr. Reinhold Ewald together with
his Russian collegues will fly to the Russian space station MIR. He will
perform an extensive experimental program on board the space station.
Dr. Reinhold Ewald was a member of the substitute crew for the MIR '92
mission during which Klaus Dieter Flade (DL1MIR) participated as the first
German astronaut attending the Russian spacestation MIR. During this
mission, Hans Schlegel (DG1KIH), who was on-board of the German/USA
spacelab mission D-2, will act as a substitute crew member.
During this mission, the SAFEX equipment (Space AmateurFunk EXperiment)
will be used primarily to inform interested ham radio operators of actual
space events taking place on MIR. Due to the severe workload of astronaut
Reinhold, the QSO mode has secondary priority. Therefore, Reinhold will
use the digital voice recorder of SAFEX to automatically transmit actual
information about the mission including personal impressions.
The SAFEX equipment at the MIR space station is built by the German Hams,
operates in the 70-cm band, and works in Packet Radio (Digi & Mailbox) or
in Voice (QSO) mode (Repeater or Duplex). For detailed information, see
"The AMSAT Journal" Nov/Dec 1995.
The SAFEX modes and frequencies are as follows:
Mode Uplink Downlink CTCSS-Tone
=====================================================
Packet 435.775 MHz 437.975 MHz none
Repeater 435.750 MHz 437.950 MHz 141.3 Hz
QSO mode 435.725 MHz 437.925 MHz 151.4 Hz
Only one of these modes can be switched on at a time. At present,
the equipment works usually in the Repeater mode. During the upcoming
mission, the QSO mode will be activated. This mode includes a digital
voice recorder. The astronaut can store his recording with a recording
time up to two minutes. This recording will be transmitted automatically
at periodic intervals. According to the position of the MIR station, the
tranmissions can be received even using a handy-talkie two to three times
during a single pass.
It is important for the reception and particularly for operation with
the SAFEX equipment to become familiar with two features: Tracking and
doppler shift. This is certainly well known to those who are familiar
with satellite communication.
A good tracking program (i.e. STS Plus) can be used to track MIR and
provide such information such as azimuth, elevation, and Doppler shift
either during, or prior to a pass.
Correction of doppler shift is mandatory since there are only very short
time periods for connections on the nominal frequencies listed above.
In the 70-cm band, there is a doppler shift of 20 kHz during an overhead
pass, and this effects receiving and transmitting frequencies in opposite
ways.
Analyzing the change of the doppler shift during one pass of the MIR
station, one recognizes that at the beginning of the contact, the doppler
shift is +10 kHz for the receiving frequency, and -10 kHz for the
transmitting frequency. This doppler shift remains almost constant for
two to three minutes at the beginning of the pass, and then changes quite
rapidly at the time of closest approach, where the signs change to become
-10 kHz for TX and +10 kHz for RX, and remain so for the remainder of the
pass.
Operation via SAFEX does not require heigh transmitter power. In the
USA, QSOs have been achieved using a Handy-Talkie up to ranges of 1000 km.
In most cases, a TX-power of 10 Watts and an antenna gain of 10 dB should
be sufficient. Operators using the SAFEX repeater should realize that
depending on the attitude of the MIR station, the RX- and/or TX-Antennas
may be obscured by the structure of the spacecraft. A good downlink signal
does not necessarily imply good uplink conditions since RX- and TX-antennas
are mounted at different locations at the PRIRODA module of MIR.
A special QSL card will be distributed to those communicating via SAFEX,
or by simply copying a message relayed by the digital voice recorder.
To prove the voice transmission or a radio connection via SAFEX, the
operator must send a QSL card including a computer WAV-File on 3.5 disk
of the voice recordling. Both need to be mailed to DF0VR, Ham Radio Group
at DLR Oberpfaffenhofen, Postfach.1116, D-82230 Wessling.
[Info via the SAFEX Team and DF0VR]
* FEEDBACK/INPUT WELCOMED *
===========================
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/
PACKET : KD2BD @ KS4HR.NJ.USA.NA
INTERNET : kd2bd@amsat.org, magliaco@email.njin.net
SATELLITE : AMSAT-OSCAR-16, LUSAT-OSCAR-19
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/EX
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