There was a project to install a small rotating ring module on the ISS, but it never came to fruition. A capsule tethered to a second stage, or a pair of capsu

There was a project to install a small rotating ring module on the ISS, but it never came to fruition. A capsule tethered to a second stage, or a pair of capsules is the low-cost* way to do it. The technique was demonstrated during the Gemini missions (at very low g). *Compared to rotating space station As to why... I suspect non-ISS life science research in orbit just has no where to get funding or support.