Operationalizing differential drag control: a planning routine for the S-NET satellite formation

Abstract The growing deployment of nanosatellites in Low Earth Orbit has increased interest in aerodynamic control methods like differential drag. This technique adjusts a satellite’s attitude to vary drag and influence relative motion—without the need for propulsion. While theoretically flexible, real-world application is limited by operational constraints. Experiences from BEESAT-4 have shown that factors such as limited satellite availability and attitude control inaccuracies reduce the effectiveness of drag-based manoeuvres. This paper focuses on the S-NET formation—four 9 kg nanosatellites launched in 2018—and proposes a planning routine for practical differential drag control. The goal is to develop a flexible methodology that includes both operational constraints and uncertainties in environmental parameters. Potential manoeuvres are calculated using linearised relative motion equations and advanced models for aerodynamics and the orbital environment. By considering key limitations during planning—such as reduced availability and control accuracy—the impact of these constraints can be better understood. The analysis also accounts for uncertainties in aerodynamic parameters, offering a range of expected outcomes. The resulting planning tool supports the design of manoeuvre sequences that remain effective despite real-world challenges, offering valuable insights for future nanosatellite missions.