Modular Cubesat Radio and ARDC Grant
October 7, 2024
Author: Evan Peters VE7DZK
We are pleased to announce our partnership with ARDC on the Modular Cubesat Radio (MCR) project, a soon to be open-access initiative to develop an accessible, space grade CubeSat radio ecosystem free of ITAR restrictions, for the Amateur-satellite service.
This project was conceived during the development of our first CubeSat ORCASat, when the need for an open access, state of the art CubeSat radio system that can be developed for any Amateur band became extremely evident. While commercially available hardware that meets this description does exist, it is not open-access and often comes at prohibitive cost for many CubeSat developers - between CAD$15,000.00 and CAD$185,000.00 as of Q4 2023. The alternative option of developing hardware from scratch can be similarly unattainable, as it requires significant time investment using test and development resources that may not always be available.
The MCR aims to address this issue and support the Amateur community by creating an adaptable development framework that can serve as either an affordable drop-in system or as a good starting point for future work by more experienced entities. Ensuring components are easily purchased and not restricted by export regulations will make the MCR an accessible and far-reaching contribution to the global Amateur radio and CubeSat communities. Additionally, its low cost and ease of procurement and manufacturing will allow developers of all skill levels to work directly on the hardware, ensuring that it will not be a one off component kept under lock and key, a problem all too common with satellite components.
This goal of an accessible, collaborative, and versatile radio project closely aligns with ARDC and CfAR’s goals of HQP training, STEM education, and the advancement of space science and technology, while also upholding the spirit of Amateur radio as a whole.
Hermes Lite-2 (Left), Kria K26 (Right)
Conceptually, the MCR will feature a system on module (AMD Kria K24), a low power HF frequency software defined radio (Hermes Lite2), and up to four exchangeable RF front end modules for various Amateur bands, accompanied by software facilitating common modes of operation, such as 9600 bps FSK TT&C using AX.25. As the SDR will natively operate at HF frequencies custom front end amplifiers and transverters will be relied upon to allow the MCR to operate at high power and high RF frequencies. To aid in the development of these, a module template, and example modules for HF (amplifier) and VHF (transverter) will be developed.
All existing GNU Radio software compatible with the Hermes Lite-2 will be supported, which will allow for easy deployment of a wide range of communication experiments. In addition, the transmit bandwidth offered by this radio will be increased to facilitate transmissions which exceed the HL2’s 48 kHz. The flexibility offered by a GNU radio-enabled SDR and a robust front end ecosystem will allow the MCR to meet nearly any common Amateur CubeSat or OSCAR mission requirements.
Structure of the MCR
The MCR will serve as MARMOTSat’s payload, composed of the core SDR, computer, and the HF and VHF modules for this initial flight. This will grant the MCR flight heritage in SSO, which is important for an open source system as it establishes itself as a viable option for use in real space missions. Being able to demonstrate that the MCR functions reliably in space is just as important as building the system itself, since developers would be unlikely to tolerate the risk of launching an unproven system. Flight on MARMOTSat will eliminate doubt on the MCR’s functionality through a variety of scientific and Amateur Radio missions, including transionospheric sounding experiments, a DVB-S2 video beacon, and a VHF digipeater.
Each of MARMOTSat’s experiments will operate in specific time slots following our to be determined operations calendar. For the ionospheric sounding mission the MCR will perform a controlled LFM radar sweep across a segment of the 10m HF band during passes above the LWA observatory in New Mexico. These swept signals will be received and analyzed at the observatory to produce a 3D timescaled map of the ionosphere as it changes due to various phenomena. Also on HF, the MCR will periodically stream DVB-S2 video data from an onboard camera. This will give 10m Amateur stations an interesting signal to receive and decode into live video from space. Lastly, the MCR will also serve MARMOTSat’s most common operating mode - acting as a VHF digipeater on the 2m bands, following the well known Greencube (IO-117) scheme. This will offer Amateur operators a communications relay to experiment with while also demonstrating transverter capability within the MCR.
We are grateful for the financial support from ARDC which enables us to undertake this interesting and impactful project. Stay tuned for more updates on the development which will be posted here, and check out the Gitlab repository which will eventually host the whole MCR project.
