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1988-07-11
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SB ALL @ AMSAT $ANS-191.01
Second AO13 Motor Burn Perfect
HR AMSAT NEWS SERVICE BULLETIN 191.01 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
In the third and final segment of a flawless trek from jungle launch pad to
its orbital residence for the next millennium or so, AMSAT OSCAR 13 has
fulfilled a decade-old plan that two prior efforts failed to achieve. It's
become history's first OSCAR in a Molniya-type orbit. This momentous event
was culminated in a dramatic "go-for-broke" in-orbit maneuver consisting of a
5.5 minute burn of AO-13's kick motor. Early indications are that the burn
was perfection itself yielding close to the best expectation for orbital plane
change and apogee target.
The first step to orbit was a flawless launch to GTO (geosynchronous transfer
orbit) by the new Ariane-4 launcher of the European Space Agency June 15. All
three satellites launched by Ariane mission V-22 have now successfully
attained their final orbits.
The second step for AMSAT OSCAR 13 was taken a week after launch when, on June
22, the kick motor was ignited for the first time. The result was an
intermediate orbit with perigee at 1081 km and inclination raised to 14.3
degrees.
Beginning immediately after the first burn, re-orientation and spin up
proceeded. By Saturday, July 2, AO-13 had attained the desired second burn
attitude (-59 degrees longitude; -70 degrees latitude in the Bahn coordinate
system). By Wednesday, July 6, the spin rate reached the desired 60 rpm.
The stage was thus set for the third and climactic step. It had been decided
to raise the target perigee a bit to about 2200 km to add some margin for
error and to increase subsequent Southern Hemisphere coverage. The increased
margin for error was desired since even a relatively minor "propulsion system
hiccup" at the wrong moment could spell disaster. AO-13 could have gone down
as a man-made meteorite if the worst had happened.
The 5.5 minute rocket engine "burn" began at 21:05 UTC, July 6. The burn
added about 1 mile per second to AO-13's orbital velocity. The plane of the
orbit was raised to about 58 degrees and the perigee was raised to about 2500
km. In a word, it was "perfect".
AO-13 reached its near-Molniya orbit where two prior attempts have failed.
Phase 3A was lost in 1980 when Ariane mission L-02 failed and was destroyed.
In 1983, Phase 3B (which became AO-10) made it to GTO aboard Ariane L-06 and
achieved an initial motor burn but was unable to re-ignite the motor later
because of a suspected propulsion system leak. The Phase 3 Program began with
early planning in 1976 as a follow-on to AMSAT OSCAR 7, the first OSCAR to use
Mode B. AMSAT OSCAR 8 was built as a gap-filler when it appeared the first
Phase 3 satellite would not be available until after AO-7 died. Thus, with
AO-13 finally reaching the Phase 3 objective orbit first outlined in 1976, it
caps a 12 year-plus program costing well over $1 million.
/EX
SB ALL @ AMSAT $ANS-191.02
AO-13 Burn Precision Amazes
HR AMSAT NEWS SERVICE BULLETIN 191.02 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
In the wake of the highly successful AO-13 kick motor burn, AMSAT leaders and
members around the world were heaping praise on AMSAT-DL President Karl
Meinzer, DJ4ZC, and Peter Guelzow, DB2OS, who fine-tuned all the variables to
a state of near-perfection.
The propulsion subsystem components engineered by Dick Daniels, W4PUJ,
similarly worked to perfection. The 400 Newton bi-propellant kick motor
donated by MBB of West Germany did exactly as it was supposed to do as well.
The combination of outstanding efforts of the analysts, engineers, technicians
and command stations has established the second and final AO-13 kick motor
burn as one of the all-time technical high water marks in all of Amateur
Radio's history. According to experts in the field, the degree of precision
with which AO-13 was taken from GTO through two kick motor burns would rate
kudos in any league in the world; not just Amateur Radio.
The 5.5 minute motor burn July 6 was a "burn to depletion" exercise which
apparently used virtually every bit of propellant available. Helium pressure
dropped in the last minute or so of ignition and the burn continued unabated
in "blow-down" mode. Even when the nitrogen tetroxide and Aerozine 50 were
exhausted, the venting of the helium pressurization gas added to the total
delta V.This may have added a tenth of a degree to the inclination said W3GEY.
On a somewhat lighter note, KA9Q calculated the output of the little rocket
engine. He says: "Just the energy imparted to the kinetic energy of the
exhaust represented a power of 600 kilowatts. The additional energy used to
heat and ionize the exhaust probably brought the total power developed by the
engine to well over a megawatt. Given that the command receiver works with
signals on the order of -144 dBW, the spacecraft's "power gain" was over 200
dB. That probably makes it one of the highest gain devices ever built by
hams! (Hi)."
KA9Q provided his best estimate of the orbit as follows:
Satellite: oscar 13
Catalog number: 19216
Epoch time: 88190.00000000
Fri Jul 8 00:00:00.0 1988 UTC
Element set: ka9q-5
Inclination: 58.9522 deg
RA of node: 247.7443 deg
Eccentricity: 0.6545803
Arg of perigee: 187.1127 deg
Mean anomaly: 293.2909 deg
Mean motion: 2.09619370 rev/day
Decay rate: 0 rev/day^2
Epoch rev: 49
Semi major axis: 25789.393 km
Anom period: 686.959416 min
Apogee: 36292.717 km
Perigee: 2530.260 km
Ref perigee: 3841.08839978
Fri Jul 8 02:07:17.740 1988 UTC
/EX
SB ALL @ AMSAT $ANS-191.03
AO-13 Ops Schedule Announced
HR AMSAT NEWS SERVICE BULLETIN 191.03 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
All that remains to be done before turning on AO-13's transponders is to
re-orient the satellite to a suitable operational attitude and spin it down to
about 30 rpm. With work on bringing AO-13 to full operational readiness going
so well, initial plans for opening the satellite to operation have been
announced. If all continues to go well, AO-13 could be on the air by July 20.
Here is the preliminary AO-13 operating schedule.
Mode From Thru Duration
MA Minutes
================================================================
Off MA 225 MA 29 61 163.7
Mode B MA 30 MA 97 68 182.5
Mode L MA 98 MA 157 (daily) 60 161.0
Mode JL MA 98 MA 157 (weekends only) 60 161.0
Mode B MA 158 MA 224 67 179.8
Mode S (Mode-S operations will commence when sun angles permit;
likely in September
RUDAK Concurrent with Mode L
Each MA (Mean Anomaly) unit equals 2.6834 minutes. This is calculated by
taking the period of the orbit (686.96 minutes) and dividing it into 256 equal
parts. The MA clock resets to zero at perigee. Half way through the orbit,
the MA clock equals 128 at apogee.
Watch for possible changes to this schedule as posted on the AO-13 GB (145.812
MHz).
/EX
SB ALL @ AMSAT $ANS-191.04
Motor Burn Listeners Awestruck
HR AMSAT NEWS SERVICE BULLETIN 191.04 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
A last minute telecommunication lash up with participants on three continents
provided listeners to a special 20 meter net a breathtaking account of AO-13's
second kick motor firing July 6.
The key was AMSAT-DL's Hanspeter Kuhlen, DK1YQ, the RUDAK Project leader, who
called off the key telemetry values being sent by AO-13 just before and
during the critical motor burn. Hanspeter joined an international team linked
by telephone consisting of himself in Munich, Hans Van De Groenendahl, ZS6AKV
in Johannesburg, Junior DeCastro, PY2BJO in Sao Paulo, Jan King, W3GEY in
Colorado and Phil Karn, KA9Q, in New Jersey. The special network used an rf
link to listeners on 14.282 MHz via WA2LQQ. Listeners were logged in from 4
continents. Unfortunately for those in North America, however, the satellite
was not then in view.
ZS6AKV, with help from ZS6BTD, monitored telemetry from AO-13 as did PY2BJO.
But the key element was Hanspeter's translation of the "Q" blocks of
telemetry. As expected, 10 minutes prior to the burn, the Engineering Beacon
was switched on. Then Hanspeter began calling various telemetry readings as
the moment of truth approached. The tension mounted as he announced the
Liquid Ignition Unit (LIU) had been powered up as programmed. Everything was
armed. And time stood still for hundreds of listeners.
Just before 21:05, UTC, DK1YQ gave the word all were waiting for. The motor
valves were open! Then things began to happen fast. The temperature on the
-Z surface jumped quickly by 17 degrees as the nearby rocket engine nozzle
climbed to nearly 1800 degrees Celsius. Was the infrared radiation charring
off the special thermal coating on the -Z surface? How much hotter would it
get? Anxious engineers waited for the next "Q" block. No more rise. The
temperature stabilized.
Something was clearly happening for listeners not decoding the telemetry as
well. There was a clear change in the signal's fading pattern. It was on its
way!
Then, only 5.5 minutes later it was a done deed. With a collective sigh of
relief, the hundreds witnessing the event on the 20 meter net looked to their
computers to determine when they would first see AO-13 in its new orbit.
According to many who listened in on the special motor burn net, the sense of
participating in an historic event was palpable. All were very complimentary
of the running commentary of DK1YQ and the analysis of W3GEY and KA9Q. ZS6AKV
and PY2BJO provided excellent back-up as well.
EX/
SB ALL @ AMSAT $ANS-191.05
RS Satellite News From PA0DLO
HR AMSAT NEWS SERVICE BULLETIN 191.05 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
Richard Limebear, G3RWL, says there is interesting news about the RS
satellites from PA0DLO and UA3CR. According to PA0DLO:
Today, (July 2), UA3CR reported in the European AMSAT Net that for the time
being RS11 will be in operation. Mode A and the ROBOT will be ON all the time.
Mode K, however, will be ON Tuesdays through Fridays. It will be OFF on
Saturdays, Sundays and Mondays, according to the RS command station RS3A.
There are no plans for Mode T operations at present. Leonid also reported that
the new RS12/13 satellite systems, that are being built now, are very similar
to RS10/11. There are only small differences, e.g. in the telemetry systems.
The frequencies to be used by RS12/13 are most likely nearly the same as those
of RS10/11, so the same mode A, K and T transponders are to be expected. The
RS12/13 systems will also be built into another satellite. Launch is planned
some time during the summer of 1989. A brand new RS satellite is also being
developed now by the RS team, according to Leonid. This new satellite,
probably RS14, will carry Mode B, Mode J and possibly other transponders,
along with several other new features. This "state of the art" RS satellite
should be ready for launch in about 3 years time.
/EX
SB ALL @ AMSAT $ANS-191.06
Tracking S/W Glitch Medication
HR AMSAT NEWS SERVICE BULLETIN 191.06 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
A flurry of recent activity has occurred in connection with the N4HY QUIKTRAK
and SUPERTRAK programs. Here is a synopsis of what's been found to date.
In GNDTRACK, in line 650, it ends MC=MC+1: GOTO 670. Remove the part that
says : GOTO 670.
A fix for the "Passes cannot occur" problem found when AO-13 had a higher
eccentricity can be made by people who are running this program using
uncompiled BASIC.
In the latest version of Quiktrak.bas, lines 2780, 2790 and
2800 read:
2780 IF FNC(R0*(1#+E(I%)*COS(D1-W*P0))/A/E2)+J>ABS(L9(IQ%)*P0) THEN RETURN
2790 PRINT "PASSES CANNOT OCCUR ";K$
2800 GU%=0:FOR KD%=1 TO 6000:NEXT:RETURN
Replace ALL of these lines with: 2780 RETURN. Delete lines 2790 and 2800 in
their entirety.
Meanwhile, some minor bugs have shown up in Quiktrak 3.2 for the IBM PC and
C-64. These will be corrected and combined with several enhancements in the
new 3.3 level soon.
New features are:
(1) ansi.sys is no longer needed
(2) You will be able to have many more satellites in the kep file
(3) Editing times, etc will be more user friendly.
(4) You may autotrak from the many satellite tabular mode by using
the cursor to select.
(5) bug fixes in search and equator crossing/apogee
/EX
SB ALL @ AMSAT $ANS-191.07
Short Bursts
HR AMSAT NEWS SERVICE BULLETIN 191.07 FROM WA2LQQ
WARWICK, NY July 9, 1988
TO ALL RADIO AMATEURS BT
AMSAT has issued a Call For Papers for its Annual Space Symposium. Papers
on topics relevant to the Amateur Space Program are solicited. Deadline
for submission is September 10, 1988. The Symposium will be held in
Atlanta this year on November 9. This is a preliminary announcement only.
Details to follow ASAP. Mail abstracts and/or papers to AMSAT, P.O. Box 27,
Washington DC, 20044.
The Space Shuttle Discovery was rolled out to the launch pad early July 4.
Best estimates now place its launch in early September.
The Soviet Union launched the first of two science missions to Phobos, one of
the moons of Mars July 7. The second mission is due for launch July 12. Each
will take about 200 days to reach Mars.
Here is the current AO-10 operating schedule:
Through July 31: Mode B MA 25 to MA 235
August 1 - August 15: Mode B MA 30 to MA 240
The satellite will be unavailable for use beginning August 16 because of
predicted insufficient solar illumination and reduced battery charge. If
"FMing" of signals occur sooner that August 15, DO NOT USE AO-10 please. As
always, please use minimum power required for communications. Listen to your
nets for later updates, or to AMSAT OSCAR 13 beacons beginning in late July
for any changes to this schedule.
Here is the FO-12 operating schedule.
Mode From (UTC)
----------------
JD Jul 09 0049
DI 09 2355
JA 13 1409
D 14 1315
JA 16 1328
D 17 1235
JD 20 1356
DI 21 1301
JD 23 1141
DI 24 1020
JD 26 1033
DI 27 1141
JD 30 1100
DI Jul 31 1006
JD = Digital mode
JA = Analog mode
D = All systems off
DI = Systems off except CPU and memory
The transponders will be off at other times. The actual operating schedule may
change due to unexpected situations such as variations in available power.
/EX