Thrust tests further potential propulsion sources for small satellites

Motivated to develop new compact electric propulsion devices for small satellites, two researchers have compared the thrust of two magnetron sputtering sources. Takahashi and Miura tested a high-power impulse magnetron sputtering (HiPIMS) design and a DC magnetron sputtering (DCMS) source.

Surprisingly, they found the DCMS source had a larger thrust. While previous work has studied the thrust generated by a DCMS system, this research was the first to compare DCMS and HiPIMS.

“The discharge looks like very bright for the HiPIMS mode in visible eyes. However, the thrust measurement shows the larger thrust for the DCMS,” co-author Kazunori Takahashi said. “This surprised and excited me.”

The researchers tested the two designs by attaching the magnetron sources to a mechanical pendulum suspended in a vacuum. Using an argon gas propellant and DC or pulsed power, they were able to measure the thrust directly by watching the movement of the pendulum.

The findings showed the thrust-to-power ratio for the DCMS was higher than HiPIMS, though the velocity of the material ejecta from HiPIMS was higher. The results are consistent with previous studies on magnetron sputtering.

“At this moment, I think the DCMS is superior to the HiPIMS for the thruster,” Takahashi said. “However, we don’t need to discard the HiPIMS yet.”

Eventually, the researchers hope one such magnetron sputtering systems could be mounted on compact satellite since it does not require a neutralizer. The researchers are trying to test the thruster with alternative liquid or solid propellants to establish more compact system in principle.

Source: “Comparison of thrusts imparted by a magnetron sputtering source operated in DC and high-power impulse modes,” by Kazunori Takahashi and Hidemasa Miura, AIP Advances (2021). The article can be accessed at https://doi.org/10.1063/5.0069184 .