Hardware-in-the-loop synthesis and analysis of spacecraft micropropulsion systems

Rikard Ottemark & Johan Sundqvist

Main SupervisorProf. Reza Emami

Onboard Space Systems

Assistant SupervisorDr. Kristoffer Palmer

Nanospace

May 10, 2016

Nanosatellites• Low cost• Short production time• Technology demonstrators• Education• Time and spatial resolution

Micropropulsion systemsNanosatellite main Conventional satellite ADCSpropulsion or disturbance reduction

Micropropulsion systems• Small impulse bits• High precision• Relatively large• Relatively high power consumption

Micropropulsion systems• Minimum mass• Minimum size• Minimum power consumption• Rare

NanoSpace CubeSat propulsion module• Four 1mN thrusters

• Individually controllable

• Complete system• Propellant tank with filters and temperature control • Thruster modules with nozzle, proportional

valves, sensors, heaters• On/off solenoid valves (two barriers)• Control and I/F electronics

NanoSpace CubeSat propulsion module• ”6U” version under development

• Dual propellant storage tanks• Plenum tank• More barriers• New communication I/Fs and protocols

• Modular design• Thrusters can be placed quite freely…

NanoSpace CubeSat propulsion module• IOD on Chinese TW-1 satellite, Launched Sept 2015

• First thruster firings in November • Orbit raised by ~600 m• Thrust misbalance observed• Problem in ADCS caused spin-up

NanoSpace CubeSat propulsion module• New mission: De-spin the satellite!

• OBC off• Manual control

• Preparations for formation flying started in April• Delta-V maneuvers expected to start soon

NanoSpace CubeSat propulsion module• Two planned launches in 2017

• MIST, 3U system (KTH, SE)• GOMX-4B, 6U system (GomSpace, DK)

• Thruster upscaling• 10-30 mN butane thrusters

Simulations• EcosimPro• Propellant flow• Pressure• Temperature• State• Plenum tank

Hardware-in-the-loop simulation• Spherical air bearing• Modular cold gas system• Attitude determination• Real-time Simulink integration

Platform challenges• Minimize moment of inertia• Align mass center with center of rotation• Propellant selection