Modular and Reusable Miniature Subsystems for Small Satellites: An Example Describing Surrey’s Nanosatellite S-Band Downlink

For more than a decade, engineers at Surrey and elsewhere have been advocating a modular approach to satellite engineering, and demonstrating this approach with practical missions. The electro-mechanical modularity pioneered by Surrey and AMSAT on their microsatellites has been emulated by many groups building satellites in the faster, better, cheaper paradigm. Paradoxically, the technique is now being applied to both larger satellites (minisatellites) and smaller satellites (nanosatellites). Simultaneously, the underlying technology is advancing and functional density is increasing rapidly. The standard 330 x 330 x 30 mm module characteristic of Surrey’s early satellites is inappropriate both for nanosatellites and for the increasingly dense electronics now available. As part of the Surrey Nanosatellite Applications Program (SNAP), we have investigated a smaller, more modern modular unit based on the “Eurocard” standard. This paper describes the new modular approach, and some of the subsystem functions which can now be embedded in the 120 x 160 x 20 mm unit. Using modules based on the in-house SNAP standard, Surrey can now design minisatellites, microsatellites and nanosatellites sharing common subsystem designs where appropriate. This updated modular approach still confers benefits in flight heritage, technology insertion, redundancy, system design and analysis and manufacturing