Geostationary, Multi-Carrier Mesh Network Enabled by On Orbit Reprogrammable Commercial FPGAs

This paper describes the development and qualification of spaceflight hardware which serves as the core of a mesh network from a geostationary (GEO) orbit. The design builds upon our heritage for a high-performance single board computer (HP-SBC). Instead of a single radiation hardened Field Programmable Gate Array (FPGA), the HP-SBC uses a commercial multi-die FPGA, which greatly expands the quantity of logic cells available for firmware and also provides radiation mitigation strategies such as internal configuration scrubbing. The signal processing power of the modern commercial FPGAs is an absolute necessity and outweighs the added radiation susceptibility. Each of the four receive channels was shown to process 153 Mbps for a composite uplink and downlink rate of 1.2 Gbps. The four receive channels have 80 MHz bandwidth and are capable of demodulating 36 continuous carriers each, or they can be operated in a time division multiplexed (TDM) format depending on the firmware implementation. The system maintained Network Clock Reference (NCR) stability better than 1 part in 10 billion during an endurance test. The thermal management system was shown to dissipate loads reaching 250 Watts without issue.