Earth-Venus-Earth-Experiment (EVE)

Between March 5 and April 10, 2009, Venus once again came relatively “close” to the Earth at just under 45 million kilometers. Just in time for this planetary event, AMSAT-DL completed its newly developed 5 kW high-power transmitter for 2.45 GHz and also received a special permit for test operation.

On March 25, 2009 at 10:38 UTC, the AMSAT-DL team reached another important milestone on the way to sending its own probe to Mars. The ground and control station at the observatory Bochum sent radio signals to Venus. After covering a distance of almost 100 million kilometers (there and back) and running for around 5 minutes, the transmitted signals were received back in Bochum as an echo from the surface of Venus. This is the first time in Germany and at least in Western Europe that it has been possible to receive echoes from other planets! At the same time, this is the greatest distance ever covered in amateur radio, over a hundred times further than with EME reflections (Earth-Moon-Earth).

FFT technology with an integration time of 5 minutes was used to receive the EVE reflections. Already after an integration time of 2 minutes the reflected signals were clearly visible. Despite the rainy weather and the resulting unfavorable reception conditions, the signals from Venus were received continuously with the 20 m antenna from 10:38 UTC until it set in the evening.

The water-cooled high-performance magnetron transmitter (around 5 kW power at 2.4 GHz) developed by AMSAT-DL itself has thus passed its baptism of fire as one of the last important key components for AMSAT’s planned P5-A Mars mission.

The transmitter was built in the Central Development Laboratory (ZEL) of AMSAT-DL in Marburg and was intended to ensure communication with the Mars space probe P5-A as a command transmitter. For this purpose, the transmitter was installed in the P5-A control station at the 20m mirror of the Bochum Observatory (IUZ) on March 14.

The performance of the 20m mirror as a receiving station has already been proven several times, including the reliable reception of various satellites in Mars orbit and, last but not least, Voyager 1, the most distant man-made object at over 14.7 billion kilometers. A distance that is almost 100 times the distance between the Earth and the Sun! Another record for us.

With the receipt of its own Venus echoes, the command station is ready to control its own Mars probe, and the AMSAT team was ready to start building the P5-A space probe. In order to finance the actual construction and launch, the AMSAT-DL tried to obtain financial support from the DLR (German Aerospace Center), among others, for the approximately €20 million that was still missing as part of a DLR-AMSAT-P5A mission. Unfortunately, the project did not materialize in the end for other reasons; the time for such missions was probably still too early. However, AMSAT-DL was able to demonstrate that its approach will make cost-effective interplanetary space travel a realistic possibility in the future.