AO-13 was expected to fail in the near future after a successful life in orbit. According to the spacecraft command operators the spacecraft is now defunct. The spacecraft ceased to function early Sunday morning on 24 November 1996.

Date:          Sun, 24 Nov 1996 07:03:38 +0000
To:            amsat-bb@amsat.org
From:          Graham Ratcliff 
Subject:       AO-13 Ceased Transmitting Telemetry!!!

Hi All,

AO-13's Engineering Beacon ceased transmitting during the Q block
time-stamped AMSAT Day Number 6902 i.e. 24Nov96 @ 05:38:16 approximately MA
31 or 32 on Orbit Number 6481.

I confirmed this loss of signal with Elgar VK5ED who was also monitoring the
telemetry when the transmission stopped.

Further attempts to command AO-13 to date have been unsuccessful!!!

Therefore, it is with GREAT SADNESS that I assume that AO-13 is DEAD!!!!

Graham VK5AGR

SB AMSAT @ WW $RUH961124
Oscar-13's Final Orbits

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                       Oscar-13's Final Orbits
                       -----------------------
On perigee 6478/79, at around 1996 Nov 23 [Sat] 1140 utc Oscar-13's solar
panel #3 ceased to function due to excessive heating.

On perigee 6479/80 at around 1996 Nov 23 [Sat] 2009:30 utc panels #1,2,4,6
also stopped working, leaving only panel #5.  The transponders were switched
off by Graham VK5AGR immediately after his AOS at 1996 Nov 23 [Sat] 2315 utc,
orbit 6480 MA 99.  Orbit 6480 continued on telemetry beacon only.

AO-13 survived perigee 6481, 1996 Nov 24 [Sun] 0432 utc, perigee altitude 107
km, monitored by insomniacs in Europe.  The battery voltage was stable at
11.8 volts, much lower than the normal 14.5v.  The on-board computer and
related systems are regulated to 10.0v.

VK5AGR monitored the remainder of orbit 6481, but one solar panel proved
insufficient to sustain a basic system, and the beacon stopped transmitting
at 1996 Nov 24 [Sun] 0538:16 utc, orbit 6481, MA 34. Reset commands, which
would have left an unmodulated carrier, had no effect.

On orbit 6482 in Europe, 1996 Nov 24 [Sun] 1300 utc onwards, neither of the
beacons was detected, and the Reset command was again ineffective.

The command stations conclude that Oscar-13 is now defunct.

Re-entry is predicted for 1996 Dec 05/06 approximately, though experience with
final orbits of decaying satellites indicates an enormous degree of
uncertainty in these matters.

November's telemetry is archived at:

   ftp://ftp.amsat.org/amsat/satinfo/ao13/telemetry/9611.zip   (956kb)

The final orbits are detailed therein:

  File            From       To       Orbit MA - MA
  ---------------------------------------------------
  Q961123A.DAT   0358:25 - 1118:02    6478 25 - 243
  Q961123 .DAT   1149:28 - 1334:03    6479  4 -  56
  Q961123B.DAT   2301:09 - 2330:36    6480 86 - 101
  Q961123F.DAT   2217:12 - 0418:22    6480  6 - 247
  
  Q961124 .DAT   0432:22 - 0440:04    6481  0 -   4
  Q961124J.DAT   0456:28 - 0459:20    6481 12 -  14 
  T961124 .DAT   0505:05 - 0538:16    6481 17 -  34
  ---------------------------------------------------

Much else connected with AO-13's re-entry can be studied from

   ftp://ftp.amsat.org/amsat/satinfo/ao13/decaykep.zip         (160kb)

which includes temperature plots, keplerian elements to re-entry, and
other useful information.

The Oscar-13 command stations are/were:

  Peter   DB2OS        Graham  VK5AGR      Ian ZL1AOX
  James   G3RUH        Stacey  W4SM

They may be reached via Internet (callsign@amsat.org) and KO-23.
Please remember to state a return address clearly.


Notes prepared by James R. Miller G3RUH 1996 Nov 24 [Sun] 1545 utc