Very interesting. I work in the industry and have not heard about this concept. It appears quite a bit of low-TRL work has been done by our friends in Europe and Japan. Appears possible in the near future, especially with market pressures due to the popularity and anticipated congestion of LEO.

But holy cow, the thruster in their diagram appears to be 80% of the spacecraft volume. These aren't going to be small birds, requiring likely multiple kW to stay in orbit.

Thanks for sharing.