[altruios]

One idea that stuck out to me was an array of giant thin solar powered spinning metal Crookes radiometers magnets in a line to make a railgun-like launcher. Materially cheap to do.

Related, but not exactly what I was thinking of: https://www.centauri-dreams.org/2025/08/05/a-rotating-probe-... The original source I'm thinking of may be lost to time :( I'll keep hunting.

edit:found!

https://www.youtube.com/watch?v=MDM1COWJ2Hc