S-Band CCSDS-compliant communications layer for the AlainSat-1 CubeSat

CubeSats have evolved from educational platforms to sophisticated Earth observation missions, driving development of miniaturized subsystems with enhanced capabilities. However, CubeSat communications face challenges from limited ground station contact windows and increasing data volumes. Modern spacecraft address this using higher frequency bands (S-band, X-band) for payload data transmission while maintaining UHF links for telemetry. AlainSat-1, a 3U CubeSat developed by UAE's National Space Science and Technology Center, was launched January 14, 2025, into sun-synchronous orbit at 575 km. The mission hosts the RITA payload for soil moisture and vegetation analysis using L-band radiometry and hyperspectral imaging. This paper presents the S-Band CCSDS-compliant communications system implementation achieving 1.43 Mbps data rates.