OSCAR 40

OSCAR 40
Type:	Amateur radio satellite
Operator:	AMSAT
COSPAR-ID :	2000-072B
Mission dates
Dimensions:	650 kg at the start
Size:	Diameter 230 cm, height 70 cm
Begin:	November 16, 2000
Starting place:	Center Spatial Guyanais , ELA-3
Launcher:	Ariane 5G V135
Status:	in orbit, out of order
Orbit data
Rotation time :	1446.6 min
Orbit inclination :	6.8 °
Apogee height :	58700 km
Perigee height :	1100 km

OSCAR 40 (also called AMSAT -OSCAR 40 , COSPAR name : 2000-072B) is an amateur radio satellite in the OSCAR series. Before launch, it was the fourth phase 3 satellite to be called P3D . It was constructed under the project management of AMSAT-Germany with the participation of numerous international AMSAT organizations and on November 16, 2000 with an Ariane 5 launcher from the Center Spatial Guyanais as an additional payload next to the satellites PAS 1R , STRV 1c and 1d geostationary transfer orbit brought. The path was changed several times with the on-board engine systems.

OSCAR 40 is the largest amateur radio satellite to date. The mechanical structure consists of a hexagonal body with a diameter of 230 cm and a height of 70 cm, without antennas and engine. Two rocket motors are used for orbit changes: a 400 N liquid thruster with hydrazine and nitrogen tetroxide and a thermal arc engine (Arcjet) with NH ₃ as fuel and a thrust of 95 mN. A total of 224.3 kg of fuel were on board. The satellite is spin stabilized and has an active electromagnetic attitude control. Magnetically mounted flywheels are provided for three-axis stabilization.

The satellite has several receivers on a total of nine amateur radio bands and transmitters on six bands. Receiver and transmitter are connected via an IF matrix. Part of the transmission bandwidth is reserved for digital communication. Omnidirectional and high gain antennas are mounted on the top and bottom of the satellite.

As with the previous satellites, the on-board computer is based on a radiation-proof COSMAC 1802 processor. As a technological experiment, another computer with a StrongARM -SA-1100 microprocessor was integrated. Three digital cameras are provided for recording the earth and for navigation. A GPS receiver was installed in cooperation with NASA .

After the launch, the first orbit maneuvers were carried out in order to bring the satellite into the planned orbit. Due to an anomaly in the main engine, some parts inside the satellite were damaged and the omnidirectional antennas failed. In the further course of the mission, worldwide radio operations were mainly carried out in the S-band downlink on 2.4 GHz. For the first time, the GPS experiment provided position data from a high satellite orbit. The cameras were successfully activated and operated. The Arcjet engine could be used in cold gas operation.

In January 2004 there was apparently a complete failure of the payloads due to a malfunction in the main battery.

OSCAR 40

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