Shareware Grab Bag/Shareware Grab Bag.iso/010/amsat688.arc/AMSAT.170

Text File | 1988-06-20 | 23KB | 444 lines

*** AMSAT Bulletin 170
Date: 20 Jun 88 06:01:06 GMT
From: thumper![e-mail]  (Phil R. Karn)
Subject: AMSAT Bulletin 170

Normally I don't make editorial comments on the AMSAT Bulletins, but this
time I can't resist. Yes, Rip is even more effusive than usual; he's really
in full swing. But he's not the only one around here who's excited.  All of
us felt a tremendous sense of relief and elation when the first reports came
in that good telemetry from AO-13 had been heard.  During the actual launch,
as each booster or stage was jettisoned and the next successfully ignited,
those of us gathered around the TV jumped up and cheered like kids. We knew
there were thousands of possible failure modes for each stage of flight, but
that as the flight progressed more and more of those failure modes could no
longer happen.  And then we made it!

Posted: Sat  Jun 18, 1988   9:11 PM GMT              Msg: MGII-3591-7005
From:   VRIP
To:     IS
Subj:   NEWS.170

******************************************************************************
*                      AMSAT NA News Service Bulletins                       *
*                              NEWS170 18Jun88                               *
*  [ Copyright 1988 by AMSAT NA, The Radio Amateur Satellite Corporation.  ] *
*  [ Permission is granted for unlimited redistribution by electronic or   ] *
*  [ other means provided credit is given to AMSAT NA News Service (ANS).  ] *
*  [                    Edited for AMSAT NA by WA2LQQ.                     ] *
******************************************************************************

Headlines:

1. Ariane V-22 Launch Letter Perfect: AMSAT OSCAR 13 Is Born
2. AMSAT OSCAR 13 In Orbit, Under Control and Working Perfectly
3. Tracking System Identifies AO-13 Quickly, Positively
4. Launch Day Coverage Exceeds Highest Expectations
5. First AO-13 Kick Motor Firing Imminent
6. Telemetry From AO-13 Says All's Well
7. Plan Calls For AO-13 Transponders Not Later Than Late July
8. Cosmonauts Return After 10-Day Mission
9. Short Bursts

******************************************************************************

1. Ariane V-22 Launch Letter Perfect: AMSAT OSCAR 13 Is Born
                      {Commentary; optional for net use}

                  Prolog: Ode To A Gracious European Lady
                        (A personal tribute by WA2LQQ)

As millions around the world held their breath, focused their eyes and ears,
the countdown approached zero. The center of focus stood solemnly on the edge
of a jungle whose floor was only recently carpeted with concrete and steel.  A
20-story tall rocket called Ariane, occasionally belching puffs of frosty
fumes hundreds of degrees colder than the morning air, was about to confront
her destiny.  And on her wings rode the hopes and aspirations of nations and
of individuals; of huge industrial consortia and of solitary craftsman.

But then the waiting was over.  As if released from a huge bow, this metallic
arrow with her precious cargo at first strained and then, with a burst of
exhilaration at being unshackled, leaped into the azure sky over the Atlantic.
Ariane-4 was on her way leaving behind a writhing quilt of orange-black and
white as if millions of tropical bird feathers had been loosed by the fury of
her voice and these were now plying the air currents on their way to the sea.

It was obvious from the start there was a lot at stake here.  But as each
mission milestone was checked off it became clear that this was a true arrow
indeed.  Second by second, minute by minute she climbed to the very ends of
the earth.  Looking back, she must have thought it all worthwhile, these years
in becoming.  Now that she WAS, these 20 minutes fulfilling her destiny were
profoundly satisfying.

And before most realized it, it WAS time.  One by one the golden boxes were
gently placed in their ethereal hammocks.  Having done her job, it was time to
go.  Ariane, this gracious European lady, turned and faded from view.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

2. AMSAT OSCAR 13 In Orbit, Under Control and Working Perfectly

Amateur Radio is celebrating the birth of a new star as it welcomes AMSAT
OSCAR 13.  The newest OSCAR came to life right on schedule last Wednesday
after a letter-perfect launch by the new Ariane-4.  Elated listeners around
the world listened in on an international teleconference network as the launch
ticked off every milestone on schedule.  Two hours and 50 minutes after
launch, AO-13 sprang to life, its first telemetry indicating it was alive and
well.

The weather was perfect for the launch.  Skies over the Kourou Space Center in
French Guiana were clear and blue.  After a six minute hold, the 20-story tall
Ariane-4 three-stage rocket leaped from the jungle floor with its cargo of
three communications satellites.  Launch time was put at 11:19:04.33 UTC or
just over 6 minutes into the first of two launch windows.  Performance of the
launcher was apparently perfect and the planned trajectory was followed with
negligible deviations.

Twenty minutes into the mission, Meteosat was the first satellite to be
deployed followed 4 seconds later by Phase 3C in its canister.  Finally,
Panamsat sprang from the SPELDA and it too became a new earth satellite.  But
it would be another 60 minutes before AO-13 would be officially born.  For a
full hour it rode within its metallic cocoon; the cylindrical carrying
structure.

Then, at exactly 12:39:04 UTC, Phase 3C was ejected from the carrying
structure and officially became AO-13. This sequence was not instrumented but
can be inferred as occurring on time by other circumstantial evidence.  It
would, however, remain unknown for another hour and a half that the ejection
had taken place OK.

The stage was set.  AO-13 was then at 27,000 km altitude over the Indian
Ocean. Would the beacon be heard as expected?

At precisely 14:03:38 UTC the new babe uttered its first telemetry.  This was
immediately acquired by listeners across the Pacific and Indian Oceans. AO-13
was not only BORN but unequivocal in its birth cries.  It was alive, well and
anxious to tell the world of its existence.  ZL1AOX reported the beacon on
145.812 MHz steady and strong.  The telemetry values showed all important
parameters were "on the money".  The temperature was about 10 degrees C. Power
was good. Spin was 7.9 rpm.  Pressure in the Helium tank was nominal.  In
general, this was a very healthy baby indeed!

Soon, more reports of AO-13 telemetry reception began to arrive.  JA1ANG and
JAMSAT colleagues in Japan had AOS at 14:03:55.  ZS6AKV and colleagues in SA
AMSAT had AOS virtually at the same moment.  Throughout the Indian Ocean and
Western Pacific, AO-13's footprint spread north and west and then blossomed as
apogee was approached.  By 1700 UTC, much of central Europe was in the
footprint.  Soon DB2OS would obtain AOS.  He was to initiate the first
commands, previously stored in the IHU, to begin re-orienting the spacecraft
and start the spin-up to an intermediate attitude on the way to the first kick
motor firing attitude scheduled to be accomplished by next Wednesday, June 22.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

3. Tracking System Identifies AO-13 Quickly, Positively

Thanks to the teamwork of AMSAT and government engineers and analysts, the
constellation of objects placed into orbit by Ariane V-22 was quickly sorted
out.  By Friday, June 17, all concerned were convinced they had identified
AO-13 and assigned it catalog number 83805.

Initial tracking data was available within an hour of launch as the European
Space Agency (ESA), NASA and various government radars around the world
quickly acquired and tracked the Ariane payloads Meteosat, Panamsat and AO-13.
In addition to the payload satellites, several other objects were in the
vicinity: the Ariane third stage; the SPELDA upper section and the cylindrical
carrying structure in which AO-13 has been enclosed.  Using various analytical
techniques such as spin rate and radar cross section, analysts had a pretty
good idea by Thursday which objects were which.  Then on Thursday evening both
Meteosat and Panamsat fired their kick motors and left the vicinity of the
remaining objects.

Working with AMSAT's own ranging system, command stations began ranging
Thursday.  Using the values obtained, Phil Karn, KA9Q, was able to get a good
match between AMSAT's ranging data and the ephemeris supplied by the
Millstone Hill radar.  This confirmed earlier suspicions that analysts had
correctly pegged the new OSCAR almost right from the start. AMSAT's ranging
team makes precise orbital determinations by measuring the transit time of
pulses sent to and returned from the satellite.

Here is the most recent Keplerian element set for AO-13:

Satellite: OSCAR-13
Catalog number: 83805
Epoch time:      88169.40
Element set:     Q-3
Inclination:       10.038  deg
RA of node:       244.288  deg
Eccentricity:    0.7309529
Arg of perigee:   179.622  deg
Mean anomaly:     118.878  deg
Mean motion:    2.2578838  rev/day
Decay rate:             0  rev/day^2
Epoch rev:              4

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

4. Launch Day Coverage Exceeds Highest Expectations

An unprecedented network of Amateur Radio and commercial telecommunications
facilities brought a special sense of poignancy and moment to the launch of
Phase 3C last week.  Hundreds of thousands of Amateurs in every region of the
world were tuned in to hear the countdown and then the good news of AO-13's
birth.

The AMSAT Launch Information Network Service used leased telephone lines to
link together major HF facilities in the U.S. and overseas.  Re-transmission
from nodes in England (G3RWL), Argentina (LU1AHC), Japan (JA1ANG), Southern
Africa (ZS6AKV) and others provided excellent coverage to all continents.  In
the U.S., W1AW, W6VIO, WA3NAN and W5RRR did yeoman duty in blanketing the
ionosphere with launch audio. AO-10 was in ideal position to relay news of the
launch to the Western Hemisphere and Europe.  Hundreds listened in on the
downlink of 145.957 MHz provided by WA2LQQ.

Audio feeds from NASA mission communications, Kourou and nodal managers such
as JA1ANG and LU1AHC added a realism and scope to the event.  Video broadcasts
on SPACENET 1 and Galaxy 3, together with CATV coverage on C-SPAN allowed many
to obtain multi-media coverage of the launch all in real-time.

Other outlets for the ALINS network included dozens of VHF and UHF repeaters
around the country and around the world.  Those overseas were typically fed by
the major overseas nodes via landline or by patch from excellent HF feeds from
W1AW and the other HF stations on board.

Congratulations and enthusiastic questions swamped AMSAT's phone lines
immediately after the launch.  A wave of relief and elation seems to have
swept over a large portion of the Amateur Radio community many of whom watched
or listened to the launch on ALINS and cable.

The only sour note was the disappointing C-SPAN programming.  The guests were
clearly unprepared and had to be coached by the phone-in audience as to
factual matters.  C-SPAN informally told AMSAT they realized they were in
trouble when the scheduled guest could not appear as planned.  The AMSAT video
tape which had been prepared didn't air either.  AMSAT officials called that a
"disappointment" and an "opportunity missed" but said they understood the
pressures of broadcasting.

Nevertheless, coverage by Arianespace on SPACENET 1 was superb.  Excellent
graphic depictions of major flight milestones were presented.  Bill Pasternak,
WA6ITF, says he got "outstanding" video on 1" studio tapes and will be making
3/4" U-Matic tapes available to the AMSAT Video Tape Library as possible. Tape
Librarian Tom Larson, N1CHM, will convert these to VHS for AMSAT member
viewing.

The technical quality of the ALINS was, in a word, perfect, thanks in large
measure to the planning and execution of VP of Operations Ralph Wallio, W0RPK.
Ralph had developed a comprehensive ALINS plan and updated it regularly as
changes required.  Ralph also contracted for the telebridge service, which was
simply excellent in all regards and he acted as tech control for the
teleconference as well.  In sum, it appears this was one of the most effective
uses of multi-media telecommunications in Amateur Radio history thanks in
large measure to the planning and execution of W0RPK as well as the various
coordinating managers around the world.  AO-13 ALINS was an outstanding
success and was, according to listener Skip Reymann, W6PAJ, "Amateur Radio at
its best!"

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

5. First AO-13 Kick Motor Firing Imminent

AO-13 had no sooner emitted its first telemetry than the command stations were
already poking around to see how it was.  The scene was reminiscent of a
new-born in the hands of the obstetrician: a gentle squeeze here, a little
poke there; listen to the cry; sounds like a good one!

First telemetry analysis by Ian Ashley, ZL1AOX, just after the General Beacon
was activated showed everything was indeed fine.  He then tried out the
Engineering Beacon and it proved loud and stable too.

Then, when AOS was obtained in Germany, Peter Guelzow, DB2OS, working in
conjunction with Karl Meinzer, DJ4ZC, checked the telemetry and then activated
a command pre-stored in the satellite's computer (IHU).  This began the first
of a series of about three attitude changes to position the spacecraft for the
first kick motor burn.

The attitude in Bahn coordinates on Friday was -90 degrees Longitude and -35
degrees Latitude.  According to DB2OS, that would be changed to -90/-70 by
Saturday and finally to +90/-60 by early in the week.  The satellite by then
will have been spun up to between 30 and 40 rpm.

There is some urgency in getting the first kick motor burn done as soon as
possible.  The risk is not that the satellite will de-orbit soon as earlier
reported, although it's loosing 30 to 40 km per day from apogee. The
asymmetrical drag at perigee increases uncertainty regarding actual attitude
and amounts to as much as 5 degrees according to DJ4ZC.  An error of this
magnitude could reduce the effectiveness of the motor burn.

The asymmetrical drag has the effect of changing the spin axis. It is caused
by unequal atmospheric pressure on the spacecraft as it plummets down towards
the lower reaches of the ionosphere only some 220 km (137 miles) high during
perigee passages.  AO-13's altitude spans a range of 164 to 1; that's 22 dBkm!
At perigee, it's passing through the sparse gas of the F1-layer at a velocity
of 17,480 mph so the effect of even the relatively few gas molecules it
impacts can be a significant torque changing the spin axis.

Consequently, the pre-launch plan has been modified according to KA9Q who,
with N4HY, has helped plan the kick motor burn strategy with DJ4ZC.  First,
the satellite will be spun up to 40 rpm.  Then, a burn of 20 counts will then
be done.  This should result in a delta-V of 150 meters/sec; about a third of
that previously planned for the first burn. This will raise inclination by 5
degrees (to 15 degrees) and raise perigee to 1000 km.

The new strategy will add a significant safety margin against the uncertainty
in attitude caused by the drag. The new plan will consume slightly more fuel
in the end, but the insurance is thought to be worth it.  The first burn will
consume only about 10% of the delta-V capacity of the spacecraft. Assuming the
attitude maneuvers go according to plan, the first burn could occur this
coming Wednesday.  Then, with a comfortably high perigee, the burns into final
orbit could be planned a bit more leisurely, according to KA9Q.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

6. Telemetry From AO-13 Says All's Well

AO-13's telemetry is its link to the outside world in terms of what's going on
in the satellite and how it "feels"; its health status. The telemetry is sent
in three forms.  The primary mode is digital data sent in a 400 baud, BPSK
(Bi-Phase Shift Keyed) stream.  This requires a special demodulator.  (Such a
demodulator is described in "Ham Radio" magazine for April, 1985.) On the hour
and half hour, as a concession to tradition, 10 wpm CW reports are made.
Then, at 15 and 45 minutes past each hour, RTTY messages using Baudot code at
50 baud, about 60 wpm, are sent.  The BPSK message contains the full telemetry
suite and narrative messages as well.  The birthday greeting in message QTC
001 was sent in five languages.

A new telemetry software package has been developed under the auspices of
AMSAT-VK and is now being handled in the U.S. by Project OSCAR according to
Project OSCAR President Ross Forbes, WB6GFJ. The software for IBM-PCs and
compatibles will decode Phase 3C 400 baud PSK telemetry via the RS-232
communications port COM1 using the G3RUH PSK Demodulator as published in
"Wireless World" Oct/Nov 1984 and "Ham Radio" in April 1985.  The current
version (V0.5) of the software basically decodes AO-10 telemetry but has been
modified to accommodate the latest Phase 3C channel allocations. An updated
version is being prepared now that AO-13 telemetry has been calibrated.  For
further details, please contact AMSAT-Australia P.O. Box 2141, Adelaide, South
Australia Postcode 5001. Information may also be obtained from Project OSCAR
P.O. Box 1136 Los Altos, CA, 94023. An SASE would be appreciated.

The TAPR DSP project will also result in a hardware/software package capable
of decoding AO-13 telemetry AMSAT has been advised.

The revised AO-13 telemetry table which updates details published in ASR, QST
and the Launch Info Kit, is now being distributed.  On packet BBS, it was
released in two parts called ALINS.009 and ALINS.010.  The updated table will
appear in the next ASR.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

7. Plan Calls For AO-13 Transponders Not Later Than Late July

AMSAT officials say we're still on track for first AO-13 transponder
operations within 4 to 6 weeks of launch.  So prospective operators should
look forward being on AO-13 not later than August 1 if the kick motor burns
all go according to plan.

AO-13 carries 4 transponders ranging in frequency from 145 to 2400 MHz.  Two
of the transponders are broadband, linear repeaters; one is suitable for FM
only; one is a type of Digipeater optimized for AO-13 use. Details of these
transponders can be found in several current descriptive articles in the
Amateur Radio print media.  Among these are articles in the current (June 88)
QST and May "73" magazines.

Here are the AO-13 operating frequencies. The operating bandplan and schedule
will be announced soon.

Mode B:  Uplink:      435.420 - 435.570 MHz
         Downlink:    145.975 - 145.825 MHz
         GB:          145.812 MHz
         EB:          145.985 MHz

Mode JL: L Uplink:   1269.620 - 1269.330 MHz
         J Uplink:    144.425 -  144.475 MHz
         RUDAK up:   1269.710 MHz
         L Downlink:  435.715 -  436.005 MHz
         J Downlink:  435.990 -  435.940 MHz
         RUDAK down:  435.677 MHz (Also the EB)
         GB:          435.651 MHz

Mode S:  Uplink:      435.601 -  435.637 MHz
         Downlink:   2400.711 - 2400.747 MHz
         Beacon:     2400.325 MHz

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

8. Cosmonauts Return After 10-Day Mission

The joint Soviet/Bulgarian cosmonaut crew returned safely from the orbital
station MIR to the steppes of Kazakhstan on Friday, June 17.  Soviet flight
commander Anatoly Solovyov, flight engineer Viktor Savinykh, and Bulgarian
research cosmonaut Alexander Alexandrov touched down just after 2 PM local
time (1000 UTC) in their Soyuz descent module after completing a ten day
mission to the permanently manned complex.

They were bid farewell only hours earlier by their hosts Vladimir Titov and
Musa Manarov who had gone over six months without guests aboard their orbiting
home.  The team had worked jointly on 46 experiments during their stay and in
keeping with standard Soviet practice, brought home the older TM-4 spacecraft
leaving the newer TM-5 attached to the station.

Within minutes of the safe landing of the 63rd manned Soviet spaceflight, all
three crewmen were awarded the Order of Lenin, the Gold Star Medal and the
title Hero of the Soviet Union.

The resident crew, Titov and Manarov, are expecting guests again later this
summer when a Soviet/Afghan crew blasts off August 29 from the Baikonur
Cosmodrome for the MIR station and again in November when a Soviet/French team
visits for 30 days.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

9. Short Bursts

A glitch in tracking AO-13 with some versions of the N4HY Quiktrak program
has shown up.  Apparently it has something to do with the eccentricity of
AO-13's current (GTO) orbit.  N4HY says he's looking into a fix.  In any case,
the problem will probably go away when the eccentricity is reduced as a result
of the first kick motor firing planned for this coming week.

                                     ***

Handsome posters of AMSAT OSCAR 13 in orbit are now available from AMSAT HQ.
Call or write to obtain yours.

                                     ***

Here is the AO-10 operating schedule:

             From June 15 thru June 30:      MA 30 through MA 230

Please use minimum power required for communications.

                                     ***

Here is the FO-12 operating schedule.

Mode  From (UTC)
----------------
JD  Jun 18  0533   JD = Digital mode
D       19  0439   JA = Analog mode
JA      22  0156   D  = All systems off
D       23  0304   DI = Systems off except CPU and memory
JA      25  0318
D       27  0131
JA      29  0143
D   Jun 30  0049
JA  Jul 02  0103
D       04  0116
JD*     07  1530
JD      07  1935
DI      08  0143
JD      09  0049
DI      09  2355
JA      13  1409
D   Jul 14  1315

*From 1530 to 1732 UTC, July 7, acquisition of telemetry will be every 2
seconds.  The mailbox will be disabled during this interval.

The transponders will be off at other times. The actual operating schedule may
change due to unexpected situations such as variations in available power.

******************************************************************************