Plasma Brake Payloads onboard CubeSat Missions of FS-1, EC-2, and FS-1p

 

We have developed a Coulomb drag propulsion device that accommodates a 50-m electrostatic tether that can be biased to a high voltage with respect to the ambient space plasma. The high voltage electrostatic sheath around the tether serves as an obstacle that perturbates the plasma mass flow causing Coulomb drag and a net propulsive force to the tether-spacecraft system. The ultimate objective for our device is to measure the Coulomb drag effect for the first time in space and to demonstrate that the Plasma Brake can be mass-effectively and safely used for orbital braking of spacecraft and space junk to mitigate the space debris 

 

Our device has been designed for 3-unit CubeSats or larger platforms. We have already built and integrated two of them into CubeSats of FORESAIL-1 and ESTCube-2. These were launched in 2022 and 2023, respectively. However, due to communication problems and launch pod failure, we were not able to carry out the Coulomb drag tests. Presently, the third Plasma Brake flight module has been delivered for the integration into FORESAIL-1p to be launched in Autumn 2025, thumbs up.

 

The key components of the device are a reeling system for the tether deployment and a high-voltage power system. The deployment is based on the centrifugal force provided by the spin-stabilised satellite platform. The reeling is driven by a stepper motor embedded and supported by a ceramic bearing inside the tether reel. The deployment system is covered and supported against launch vibrations by the tether chamber. There are three launch locks mounted to the tether chamber to secure the tether reel and tether tip mass during the launch. In addition to the high-voltage electronics, there is the electric power system and control electronics, most importantly, the stepper motor driver and microcontroller unit. The high-voltage system also monitors the tether voltage and current since these are expected to vary depending on the ionospheric density. In this presentation, we describe the device in further details and cover the basics of the Coulomb drag, and Plasma Brake operations in orbit.