OSCAR 40 (also known as AMSAT- OSCAR 40, COSPAR Designation: 2000 - 072B ) is an amateur radio satellite OSCAR - series. Before starting he wore as a fourth satellite of phase 3, the designation P3D. It was constructed under the project leadership of AMSAT Germany with the participation of numerous international AMSAT organizations and was on 16 November 2000 by an Ariane 5 rocket from the Guiana Space Centre as an additional payload in addition to the satellite PAS 1R, STRV 1c and 1d in a brought geostationary transfer orbit. The sheet was amended several times in the ship's engine systems.

OSCAR 40 is the biggest amateur radio satellite. 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 engines are used for train changes: a 400 -N liquid engine with hydrazine and nitrogen tetroxide and a thermal arcjet ( Arcjet ) with NH3 as a fuel and a thrust of 95 mN. Overall, 224.3 kg of fuel on board were. The satellite is spin- stabilized and has an active electromagnetic position control. For three-axis stabilization magnetically suspended flywheels are provided.

The satellite has multiple recipients at a total of nine amateur radio bands and channels to six bands. The receiver and transmitter are connected to an IF matrix. A part of the transmission bandwidth is reserved for digital communication. Omnidirectional antennas and high gain antennas are mounted on the top and bottom of the satellite.

The on-board computer is based as previous satellites on a radiation- resistant 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. In collaboration with NASA, a GPS receiver was installed.

After the start of the first orbital maneuvers have been made, to cause the satellite to the planned orbit. Due to an anomaly in the main engine this involved corruption of some parts in the satellite interior and the failure of the omni-directional antennas. In the further course of mission worldwide radio operation was mainly carried out in the S-band downlink to 2.4 GHz. The GPS experiment provided the first position data from a high orbit satellites. The cameras were successfully activated and operated. The Arcjet thruster could be used in cold-gas operation.

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