Heimdall - an amateur moon companion

Heimdall (ancient scand. Heimdallr) is a god from German-Scandinavian mythology. His house - Himinbjörg ("heavenly mountains"), is located near the bridge of Bivröst, which connects the sky with the earth. The name of this god is called an amateur satellite, which in September 2018 will go into lunar orbit.

Heimdall satellite belongs to the amateur radio association for satellite radio communications ( AMSAT ). With the help of satellite repeaters, radio amateurs can conduct long-distance communications in the VHF band. Communication time on one turn of 12–20 minutes. There are quite a few radio amateurs working through our natural passive repeater - the moon. This communication technique is called EME . This type of communication is much more technically difficult than via near-earth satellites, and requires special equipment.

In 2018, the situation will change - an active amateur radio relay will be on orbit around the moon.

The satellite is made in the most common, for the time being, 6U Cubesat format (10 × 20 × 30 cm), it is stabilized along three axes and weighs about 8 kg. It will have compressed gas orientation engines for damping inertia and a star sensor for determining orientation in space. Retractable, on a gimbal, solar panels will have a power of up to 100 watts, and an electric rocket engine will be used to achieve a near-moon orbit. On one side of the device will be a combination of omnidirectional and directional patch antennas .
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The first part of the mission is to reach the circumlunar orbit; during the mission, the satellite will be tracked, telemetry will be received and controlled (TT & C). The second part is to conduct an experiment using downlink data. And in the final part of the mission, which will last until the end of the satellite’s existence, a two-way radio repeater and an analog radio repeater will be used in the lunar orbit.

Downlink
• Omnidirectional: 10.451 GHz ± 0.5 MHz
• Directional: 10.4575 GHz ± 3.5 MHz
• Analog transponder: 10.4665 GHz ± 2.0 MHz

For the first part of the mission (TT & C), the coding system 300 bps BPSK 1/2 rate viterbi Ranging 1.5 Mbps BPSK DSSS will be used. In the second part of the mission - 4.5 Mbps QPSK ½ rate DVB-S2. In the final part of the mission - 25 kbps BPSK 1/5 rate DVB-S2.

Uplink
• Omnidirectional: 5.651 GHz ± 0.5 MHz
• Directional: 5.6575 GHz ± 3.5 MHz
• Analog transponder: 5.655 GHz ± 2 MHz

It is assumed that a parabolic antenna of 1-2 meters and the equipment developed for the ground station by AMSAT will be needed to work with the satellite.

Satellite developers are among the participants of the NASA Cube Quest Challenge , the goal of which is to promote the development of innovations in the field of motion and communications of small spacecraft near the Moon and beyond.