Amateur Satellite Summary

AMSAT-OSCAR 10

Satellite Summary

Name: AMSAT-OSCAR 10 (Phase-3B)
Nasa Catalog Number: 14129
Launched: June 16, 1983
Launch vehicle: ARIANE 1-06
Launched piggyback with: European Test Satellite ECS-1
Launch location: Kourou, French Guiana
Weight: 90 kg plus fuel
Orbit: High-altitude, elliptical, synchronous-transfer, Molniya, 3997 x 35449 km
Inclination: 27 degrees
Period: 11 Hours, 39 Minutes
Size: 600 x 40 x 200 mm
Modes: B

Beacons:

145.810 MHz (General) (Unmodulated carrier)
145.987 MHz (Engineering) (Switched off)

Linear Transponders: Inverting (CW, SSB)

Mode B Uplink: 435.030 - 435.180 MHz LSB
Mode B Downlink: 145.825 - 145.975 MHz USB

Features:

Molniya Orbit - Long Communications Time

Firsts:

First amateur satellite with onboard propulsion (which did not function entirely correctly, due to collision with part of the launch vehicle after separation - hence the not-quite-Molniya-type orbit).

Status: Semi-Operational

The latest information is available from:
- Weekly Satellite Report (WSR)
- W4SM's Unofficial AO-10 Web Page

Description

AMSAT-OSCAR 10 was launched June 16, 1983. On December 1986 the main computer failed due to radiation damage. Thus, the ability to control the spacecraft was lost. It is presently operational on mode B. However, due to the inability to orient the satellite, the batteries are not always fully charged. So operation is random as AO-10 goes in and out of the sunlight. Communications are encouraged when the transponder is operational and, of course, discouraged when the downlink frequency is FMing.

The following is an informative note from Peter, DB2OS:

The onboard computer of AMSAT-OSCAR 10 failed due to radiation damage of the memory chips. Since then we have had no more attitude control and due to seasonal changes of the alignment of the Sun in respect to the solar panels, there are times were no electrical power will be available and the spacecraft goes into hibernation until the sunangle is better again. The battery is indeed fully depleted and due to the harsh environment it may already have lost its capability to store electrical energy.

If the electrical power from the solar array is getting marginal, the transponders starts FMing,which means that your carrier is moving back and forth in frequency depending on the current transponder load. During those "undervoltage conditions," it sometimes happens that the onboard computer (IHU) starts to execute random code from the memory, which might turn transponders or beacons randomly on/off. The beacon may even sound like OSCAR-13, but that's mainly because the 400 Bit/s BPSK is done by hardware; indeed it contains no useful information. Under normal circumstances the transponder is on and the general beacon is transmitting only an unmodulated carrier.

Satellite operators frequently ask "what is the attitude of Oscar-10", or "can I have ALON/ALAT values for my computer program." Here's the analysis written by James Miller, G3RUH.

See also W4SM's AO-10 Update for the latest.

References

J.A. King, "Phase III: Toward the Ultimate Amateur Satellite," Part 1, QST, Jun 1977, pp 11-14.
J.A. King, "Phase III: Toward the Ultimate Amateur Satellite," Part 2, QST, Jul 1977, pp 52-55.
J.A. King, "Phase III: Toward the Ultimate Amateur Satellite," Part 3, QST, Aug 1977, pp 11-13.
Amsat Satellite Report, No. 60, Aug 1 and No. 62, Sep 7, 1983.
Jan King, et al, "OSCAR at 25: The Amateur Space Program Comes of Age," QST, Dec 1986, p 15.
Martin Davidoff, Satellite Experimenter's Handbook, 2nd edition, The American Radio Relay League, Newington, CT., 1990.
Keith Berglund, A Beginner's Guide to OSCAR-13, AMSAT

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Last update May 31, 2003 - N7HPR