AMSAT-NAOSCAR-13's Final Orbits

Adapted from a bulletin (BID $RUH961124) from James Miller, G3RUH, OSCAR-13 command station.


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, and 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] 2314:15 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 (956 KB) is archived for downloading.

The final orbits are detailed therein:

FileFromToOrbitMA - MA
Q961123A.DAT0358:251118:02647825 - 243
Q961123 .DAT1149:281334:0364794 - 56
Q961123B.DAT2301:092330:36648086 - 101
Q961123F.DAT2217:120418:2264806 - 247
Q961124 .DAT0432:220440:0464810 - 4
Q961124J.DAT0456:280459:20648112 - 14
T961124 .DAT0505:050538:16648117 - 34

Much else connected with AO-13's re-entry can be studied from decaykep.zip (160 KB) 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. HTML conversion by and feedback to KB5MU.

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