Varda Space is working on this. The term "factories in space" in their case doesn't match the images it brings to mind. They use relatively small devices that run chemical processes for medication production that work much better in zero gravity. I understood it in essence to work that way that you shoot the device into space, the reactions take place and the thing crashes back to earth for collection. Supposedly it has a huge cost advantage and should fit what the author wants.
More info: https://open.spotify.com/episode/3kmdbUZYWIJ5wujPDRfBvD