dna@dsd.UUCP (03/04/84)
TO: HM
FROM: PK
SENT: 03 MAR 84 06:13:34
READ: 03 MAR 84 14:46:42
I've been posting comments on UO-11 on the telemail AMSAT bb.
Rather than repeat the whole thing here, I'll summarize the situation as
I know it.
The last reported UO-11 frames are from Graham Radcliff in Australia.
The last frame he sent me on Telemail was at about 23:15 UTC; this is
about 45 minutes before the no-show at KA9Q. The path of the satellite
between these two times took it over Antarctica and up the Atlantic
Ocean. There was visibility in most of eastern South America, Falkland
and Ascension Islands. In particular, Falkland's pass included the start
of the half-hour eclipse which occurs on each orbit. Anybody know
anyone down there?
I've written a telemetry decoding program in "C" for anyone who wants
it. Harold has a copy and he's bringing it up on his system. From my
examination of Graham's frames, nothing really looks suspicious.
Rather than post it here (the decoded version of his frames is 116K!),
I'll give a summary.
Temperatures were running cool, but not exceptionally so for a
spacecraft, but remember it had been in sunlight for a while and was
about to enter eclipse in about 20 minutes.
The battery was sitting at a stable +6 C, the battery voltage at a
little over +14 with little fluctuations, and all the solar arrays were
producing power (but not at the same time, of course).
The battery charge/discharge current was fluctuating rapidly,
sometimes going slightly negative but usually running at a few hundred
mA positive. The spacecraft was obviously spinning fairly fast as
indicated by the rapidly changing solar array and battery currents.
Regulated voltages looked reasonable. From a phone conversation with
Harold, none of the various currents seemed out of line. The warmest
temperature reading was, of course, the 2m beacon: +16.6C. It was putting
out about 650 mw of RF.
Facet temperatures were cool, ranging from -5C to 0C, except the -Y facet
with a consistent warm reading of +12.8C.
The mode bits were as expected, 1802 computer, nav mag and 2m beacon
about the only things turned on. The navigation magnetometer seemed to
be producing numbers. No activity was seen on any of the command
receivers (but they were drawing supply current). The computer was on,
but not commanding the spacecraft. The command watchdog timer was
enabled; according to Harold, this timer runs for about 20 days and
turns off the beacons if no command is heard from the ground in this
time.
I'm stumped.
Phil
TO: HM
FROM: PK
SENT: 03 MAR 84 13:48:41
READ: 03 MAR 84 14:48:18
Tom (with copy to everyone),
Here's the predicted AOS times for my next pass as derived from all of
the UO-11 element sets on hand:
prelim: 14:13:21.7
MH: 14:12:45.1
Nasa 1: 14:15:52.5
Nasa 2: 14:15:53.6
Nasa 3: 14:14:02.5
In particular, that last one (Nasa set #3) looks suspicious. Without a
beacon to track, we could very easily be looking at the wrong object.
Phil
TO: HM
FROM: PK
SENT: 03 MAR 84 13:52:00
READ: 03 MAR 84 14:48:40
Larry,
I'm having pretty good luck in decoding those frames you sent me. So
far, I can't find a clue - except I'm wondering about the state of
the battery charge/discharge line. I can't figure out if it's
functioning properly or not, as I see wild excursions. I tend
to discount these because the battery voltage is reasonably stable,
varying as you would expect due to eclipses and s/c loading. Can you
tell me from which parts of orbits these frames are from?
Phil
P.S. If you want any decoded frames, just yell. They're large,
though.
TO: HM
FROM: TC
SENT: 03 MAR 84 16:13:58
READ: 03 MAR 84 21:31:05
In addition to Phil's analysis of Graham's data, I asked Bob Diersing
to try decoding it. Bob has sent me a LARGE text file of the decoded
data which agrees with Phil's analysis. If anybody want to see all or
part, I have it captured here on disk.
Tom
TO: HM
FROM: HP
SENT: 03 MAR 84 17:17:14
READ: 03 MAR 84 21:31:26
Saturday morning news
Just got off the phone with Roger Peal. Last nite they found an error in the
software which was loaded into the 1802 computer that caused the beacon
to stay on only 1/10 the time they thought, thus the second pass had
an 8 minute beacon instead of 80, and the third pass had an hour beacon
instead of 10 hours. Thus there is now a good reason for hearing it
in VK but not in the US. It would have gone off in the south Atlantic.
(Phil, can you compute where it would have gone off? Assume the program
was loaded 2/3 of the way thru the last UK pass.)
This doesn't explain why the beacon won't come back on. A possible
explaination follows. The was a problem with the two meter beacon that
caused it to be intermittent. One of the osc. stages would occasionally
not lock up fast, and the beacon would draw more power than the power
module would allow it to. This limited the current it could get and it
never locked up. The fixed at VAFB was to increase the current limit for
the beacon. The problem never re-occurred. One theory says that when
the s/c got colder, it drew more current during the start up time, and
has locked up again. By the way, all tlm reviewed shows a healthy s/c
that is not too cold for normal operation.
Assuming the 2 meter beacon is locked up, it may be putting out enuff
hash to block the two and 70 cm receivers. It may be possible to hear
this hash with enuff gain on the ground. Can someone with a big
array point it the right place with a spectrum analyiser and look
for dopplering noise?
Roger promises to put a more complete status summary on TM soon, there
TM link in the UK has been down for several hours.
Keep listening.
Harold.
Posted: Sat Mar 3, 1984 7:24 PM GMT Msg: AGIE-1731-2616
From: MSWEETING
To: AMSAT
Subj: Oscar-11 status
Sorry for the ominous silence from UoS - our Telemail PSS link
has been down for the past day or so. Thanks for the
telemetry and phone calls received since launch.
We have discovered a problem in the program which was run on
the Oscar-11 computer on orbits 2 & 3, causing them both to
turn the 2m beacon off in an eighth of the time intended.
No-one commented that the previous report from us saying that
the 2m beacon was on for 80 minutes on orbit 2 was incorrect.
So on orbit 2, telemetry was transmitted for 10 minutes from
shortly before LOS at Surrey, and on orbit 3 for 75 minutes
from 22:30:20 until 23:45:20 - just short of the east coast of
the USA.
Since we have now a positive reason why the beacon went off
late Thursday evening (GMT), our worst fears of a catastrophic
failure look less likely. Discussions at Surrey and very
recently with Harold, NK6K, suggest that a more plausible
explanation is that the 2m beacon, when cold after being off
for 7 hours, failed to oscillate properly on power-on. An
effect similar to this was seen during the first cold cycle of
Thermal Vacuum testing, however the problem was later tracked
down and rectified. The cause was a large current surge on
power-up causing the power distribution to foldback
sufficiently to prevent full power-up.
Discussion of the remedy for this scenario is still in
progress, so any suggestions would be gratefully received.
Use of the 1.2GHz uplink is a possibility, since the 70cm
uplink shares an antenna with 2m. Harold is already looking at
whether the non-nominal signals can be received from the 2m
beacon using large antenna arrays in the L.A. area.
Roger
Posted: Sat Mar 3, 1984 8:04 PM GMT Msg: QGIE-1731-2652
From: VRIP
To: HPRICE,MSWEETING
CC: AMSAT
Subj: UO-11 Report of W4DAQ
I have just debriefed W4DAQ on his observation of this morning.
Here are the salient facts as he reported them to me a few moments ago.
His QTH is Demoplis, Alabama.
Using NASA element set #2 he had predicted AOS of 3 Mar 1418 UTC; actual
AOS 1423 @ 120 az. Actual LOS at 180 az at 1436 UTC.
Signals heard on 145.825 characterized as very weak; <S1 over S0 floor.
Station comprises KLM 16C, Lunar GaAsFET at antenna, 15 meters foam coax,
FT-221R rcvr.
Signals had "slight" Doppler. Mack noted sense shift too. At AOS RHCP=LHCP.
At (approaching) LOS, RHCP predominated.
Mack's telephone number is 205-289-1225.
73 to all, Rip.
Posted: Sat Mar 3, 1984 8:19 PM GMT Msg: RGIE-1731-2673
From: VRIP
To: HPRICE, MSWEETING
CC: AMSAT
Subj: UO-11 Report of W4DAQ, Rev 1
Further discussion with Mack has revealed the following.
First, a correction. His "predicted" AOS and LOS times were based
on the prelaunch, repeat, prelaunch element set from PKARN rather than
the NASA set #2 which I indiacted a few moments ago.
He said that the times predicted by the prelaunch set and the NASA #2
differed by about two minutes.
Second, Mack also had AOS last night. Details as follows.
1.Predicted AOS (prelaunch elements): 0352 UTC 3 Mar
2. Actual AOS 0358 UTC 3 Mar at 300 deg az. LOS @ 0412 UTC 3 Mar.
3. He added another 15dB of active gain to the circuit with an
additional preamp in the shack.
4. He emphasized his certainty that what he was hearing was of space origin.
5. He further asserted he could detect no modulation whatsoever on the
"good sine wave" audio he was hearing. It could not be heard in FM
detection mode. Only SSB.
TO: HM
FROM: TC
SENT: 03 MAR 84 22:16:46
READ: 04 MAR 84 00:56:51
Here is a 4th set of Keplerian elements. The Goddard switchboard
called me at 4AM (!!!!!) to read them to me. That's above and
beyond the call of duty -- Tom
Object: 1984-021B = NASA # 14781
NASA El.Set: # 4
Epoch: 84063.16028249
Incl: 98.2530
RAAN: 125.6123
Eccr: 0.0012258
Arg.Perg: 255.4198
Mean Anom: 104.4947
Mean Motion: 14.61820641
Drag: +0.00000476
Posted: Sat Mar 3, 1984 1:51 AM PST Msg: HGIE-1731-1983
From: RZWIRKO
To: AMSAT
Subj: UOS MYSTERY-CLUE?
JUST A BIT OF INFO WHICH I SHOULD HAVE PUT ON EARLIER:
ON THURSDAY NIGHT EST AROUND 7pm EST THERE WAS A MAGNETIC
STORM IN PROGRESS. SIGNALS WERE NOTED ON 144MHZ COMING
IN WITH TYPICAL AURORAL NOTE. BEST DX HEARD WAS FROM THE
CHICAGO,IL AREA. SIGNALS WERE S9 FROM THAT DISTANCE HR IN
MD, INDICATING A PRETTY HEAVY BIT OF IONIZATION. ANY
CHANCE THAT THIS SOLAR/MAGNETIC ACTIVITY HAD ANY EFFECT ON
UOSAT-OSCAR-11??
73, RICH K1HTV
Posted: Sat Mar 3, 1984 4:01 AM PST Msg: AGIE-1731-2036
From: RZWIRKO
To: MSWEETING
CC: AMSAT
Subj: CLUE??
Martin & UOS team,
I didn't think much of it thursday night, but now that I've
heard that there is a problem, I thought that I'd relay the
info that on Thursday evening EST,(around 00 UTC 2 March)
there was a pretty good aurora going on here in the States.
I was checking out my modem on my weak signal source at 144.1
MHz and heard the LOUD cw QRM from signals out of the Chicago
Illinois area with the very familiar auroral buzz sound.
The last report of signal reception of U-O-11 was around 23:15
UTC in Australia. I wonder if the magnetic activity had any
effect on the bird. Phil mentioned that the navigation magnetometer seemed to be
producing numbers. Might there be a clue in that data?
73, Rich K1HTV
Posted: Sat Mar 3, 1984 10:24 AM PST Msg: RGIE-1731-2513
From: RDIERSING
To: VRIP,DLOUGHMILLER
CC: AMSAT
Subj: IBM PC program bug
There is an error in the W3IWI orbit prediction program when computing
the day number after Feb. 29.
900 IF M > 2 THEN D8 = D8 + F9
****** SHOULD BE ******
900 IF MONTH > 2 THEN D8 = D8 + F9
This one will surely appear on the nets and the fix is simple enough
that it can be communicated. I will check to see if this problem
exists in other versions of the program and advise.
73, Bob
Posted: Sat Mar 3, 1984 1:23 PM PST Msg: BGIE-1731-2757
From: VRIP
To: MSWEETING,HPRICE
CC: AMSAT
Subj: Big Ears To the Rescue
Dave Olean, K1WHS, will be listening for UO-11 on its expected passes
tonite beginning abt 23:xx UTC. Will advise.
Posted: Sat Mar 3, 1984 1:25 PM PST Msg: EGIE-1731-2760
From: VRIP
To: MSWEETING,HPRICE
CC: AMSAT
Subj: K1WHS
It occurs that a few may not recall that K1WHS's EME array is one of the
most sensitive in amateur hands. I thought I'd mention it. 73.
Posted: Sat Mar 3, 1984 5:54 PM PST Msg: IGIE-1731-2964
From: VRIP
To: AMSAT
Subj: UO-11 (Non) Reception Report
K1WHS, KA9Q and WA2LQQ negative report for 23:40 (3 Mar) and 01:20 (4 Mar)
orbits. If K1WHS's 26dBd array couldn't pick it up, chances are very
slim there was anything going on with any spectral density at all! Dave
can hear the static from a crickets legs rubbing tohgether at 10,000 km
(it is alleged!) Sri but nothing stirring here. 73 de Dave, Phil, Rip