Scientists have invented a slip ring assembly that can tackle the high-voltage needs of next-gen satellites that increases the satellite’s lifespan
Satellites play a very important role in the internet and communication and help us with agricultural problems, climate change, positioning and navigation, and many more. To improve its durability and performance, researchers from the Swiss Plasma Center (SPC) of EPFL and Beyond Gravity have implemented a slip ring assembly that increases voltages in satellites, elevating the range from the current 28–100 Volts to 300–600 Volts, resulting in increased robustness against electrical failures.
To use the power generated by solar panels, satellites are equipped with a “slip ring assembly,” which is a component designed to transfer electrical power to electrical power systems such as onboard computers, traveling wave tubes, data-gathering equipment, and power thrusters while rotating. The slip ring does this by using sliding electrical contacts: a rotating ring and a stationary brush—the “wiper.” As the system rotates in a satellite, the wiper slides along the ring’s surface, transferring electrical current at low voltage.
The challenges that SPC researchers wish to meet with the growing need for higher voltages in satellites are
- To overcome operating a slip ring assembly the challenges in space, to remove the risk of electrical breakdown that could permanently damage the satellite.
- To overcome the significant pressure changes that a satellite undergoes, from the atmospheric pressure at the launch to the deep vacuum of space. Because the isolation of electrical components in satellites usually relies on vacuum conditions, in the absence of any gas pressure. Proposed solutions have so far involved increasingly complex configurations of electrical circuits that can end up getting in the way of the satellite’s function.
- Lastly, monitor the number of turns the ring must make per day, as after a certain amount of time can have adverse effects on its function.
As the Advanced Slip Ring for high voltage Mechanism project demanded, it aims to “develop, manufacture and test a breadboard model in a relevant environment.” The SPC researchers provided expertise and technical support to Beyond Gravity in the new slip ring design and testing under conditions that replicate a satellite’s lifespan. The slip ring proved to function within 400-500 Volts (and 8 A) from very low pressures (10-5 mbar) to the most critical pressure values (~1 mbar), with a resulting transferred power of up to 40 kW. It maintained this output even after 25,000 turns—by comparison, a geostationary satellite’s slip ring assembly will perform around 11,000 turns after 30 years of operation.
“The success of this project stems from a close collaboration between academia and industry where all the partners had to closely understand each other’s needs and constraints,” says Furno. “With the new slip ring design, which will be field-tested in orbit in the upcoming years, we are paving the way for the next generation of high-power thruster satellites.”