5 GHz to 10 GHz Lunar Transponder Mission

View of Earth from the Moon AdobeStock_77398324AMSAT-NA plans 5 GHz to 10 GHz transponders on a spacecraft expected to launch in September 2018 into a Lunar orbit.

Heimdallr is a 3 axis stabilized 6U CubeSat with a mass of approximately 8 kg. It will have a Cold Gas Thruster for inertia dump and a star tracker for navigation. Deployable, gimbled solar panels will produce up to 100 watts of DC power, electric propulsion will be used to achieve lunar orbit.

There will be a combination of omni and directional patch antennas on one side of spacecraft.

The first part of mission is to provide Telemetry, Tracking, and Command (TT&C) to obtain lunar orbit. The second part is to perform the data downlink experiment while the final part is to provide a two way regenerative repeater and analog repeater in lunar orbit for lifetime of satellite.

Proposing these downlinks:
• Omni transponder: 10.451 GHz +/- 0.5 MHz
• Directional transponder: 10.4575 GHz. +/- 3.5 MHz
• Analog transponder: 10.4665 GHz. +/- 2.0 MHz

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

Proposing these Uplinks
• Omni transponder: 5.651 GHz +/- 0.5 MHz
• Directional transponder: 5.6575 GHz. +/- 3.5 MHz
• Analog transponder: 5.665 GHz. +/- 2.0 MHz

A link budget is available at

It is anticipated that a 1 or 2 metre dish will be required using the AMSAT designed ground station equipment.

Source IARU Satellite Frequency Coordination Status pages http://www.amsat.org.uk/iaru/

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