Low-cost cold-gas reaction control system for sloshsat FLEVO small satellite

A low-cost cold-gas reaction control system (RCS) has been designed and developed for liquid-slosh experiments in the ESA-sponsored Sloshsat FLEVO (Facility for Liquid Experimentation and Verification in Orbit) small satellite. Four spherical carbon/epoxy-wound stainless-steel tanks of a "leak before burst" design store 1.6 kg of the gaseous nitrogen propellant at 473 bars corresponding to 20 degrees C. Each tank is equipped with an accessories assembly, which includes a pyrovalve of a self-seal design and a filter. The cold-gas propellant is supplied to 12 especially developed 0.8-N thrusters at a steady regulated pressure. Before reaching the thrusters, the gas passes through a surge damper, a two-stage pressure regulating assembly, and a latch valve. For safety and redundancy, two relief valves are mounted downstream of the regulators. A breadboard test system, which completely simulates the pneumatic nature of the Sloshsat RCS, was used for ground-test evaluation of the RCS performance in various modes of operation (continuous and pulses of various duty cycles) and for development experiments. Thruster opening and closing response times were less than 5 ms. Delivered specific impulse of 70 s in vacuum was demonstrated. The RCS successfully passed the required qualification and acceptance tests.