Session
Technical Session VII: Propulsion
Abstract
This paper presents a MEMS-based micro propulsion system with closed-loop thrust control. It is a cold gas system with butane as propellant packaged in module with the size one third of a 1U CubeSat. The module is described in terms of design, manufacturing, and test results. The development of this product is on-going but recent achievements have demonstrated that besides miniaturization also unique performance and functionality can be achieved. By using MEMS components in a closed-loop control configuration, the combination of milli-Newton thrust range, sub micro-Newton resolutions, and fast response time can be achieved. In our view, using MEMS technology and integrating the flow control valve, mass flow sensor and chamber/nozzle on a single chip is the best –if not the only- way to realize a closed-loop control thruster that can meet new tough small satellite propulsion requirements. Today, most thrusters and fluid control components are operated in ON/OFF mode and in a control system where the feed-back signal comes from sensors (such as accelerometers, sun sensors or star trackers) on-board the spacecraft. The novel MEMS devices presented here do enable both continuous/proportional and closed-loop flow control. In the application of a thruster (cold gas or chemical) this enables continuous throttling capability with a real time measurement of the delivered thrust. Such functionality does enable advanced missions such as precise formation flying or drag free flights. Furthermore, the miniaturization that comes along with the MEMS technology does also in general open up for propulsion on-board CubeSats. The MEMS-based micro propulsion module comprises four complete MEMS thruster and one centralized tank. In addition to the MEMS components e.g. valves, nozzles, and mass flow sensors it also holds front-end electronics inside the mechanical housing using the Pumpkin CubeSat interface standard. Electrical interface is 21 pins analog (0-12V) and digital (SPI).
Presentation Slides
Closed-loop Thrust Control in a MEMS-based Micro Propulsion Module for CubeSats
This paper presents a MEMS-based micro propulsion system with closed-loop thrust control. It is a cold gas system with butane as propellant packaged in module with the size one third of a 1U CubeSat. The module is described in terms of design, manufacturing, and test results. The development of this product is on-going but recent achievements have demonstrated that besides miniaturization also unique performance and functionality can be achieved. By using MEMS components in a closed-loop control configuration, the combination of milli-Newton thrust range, sub micro-Newton resolutions, and fast response time can be achieved. In our view, using MEMS technology and integrating the flow control valve, mass flow sensor and chamber/nozzle on a single chip is the best –if not the only- way to realize a closed-loop control thruster that can meet new tough small satellite propulsion requirements. Today, most thrusters and fluid control components are operated in ON/OFF mode and in a control system where the feed-back signal comes from sensors (such as accelerometers, sun sensors or star trackers) on-board the spacecraft. The novel MEMS devices presented here do enable both continuous/proportional and closed-loop flow control. In the application of a thruster (cold gas or chemical) this enables continuous throttling capability with a real time measurement of the delivered thrust. Such functionality does enable advanced missions such as precise formation flying or drag free flights. Furthermore, the miniaturization that comes along with the MEMS technology does also in general open up for propulsion on-board CubeSats. The MEMS-based micro propulsion module comprises four complete MEMS thruster and one centralized tank. In addition to the MEMS components e.g. valves, nozzles, and mass flow sensors it also holds front-end electronics inside the mechanical housing using the Pumpkin CubeSat interface standard. Electrical interface is 21 pins analog (0-12V) and digital (SPI).
