A full design for the GN Beta Drive system installed in my original 00 Gundams Dawn, Dusk, and Spectrum.
The Beta drive is smaller than the Alpha drives used by Celestial Being's main Gundams, and the Tau drives later used in mass-produced Mobile Suits. While the Beta drive is capable of indefinite GN particle generation, its rate of output exceeds its rate of generation, limiting its operational time to 48 hours before needing to stop and allow it to regenerate its GN particle reserves.
Unlike the Alpha drives, the Beta drives were not manufactured in a high-gravity Jovian environment. Instead, they were manufactured in a simulated high gravity environment within a small Celestial Being asteroid base set into a slingshot orbit, allowing the asteroid's centrifugal* force to provide high artificial gravity.
This is a design for my Gundam 00 side-story: Gundam Dawn.
Gundam Dawn (c) me
Gundam (c) Bandai/Sunrise
*Don't worry, physics/engineering majors, I'm fully aware that "centrifugal force" isn't really a thing, and is simply a means of expressing two opposing inertial forces in motion.