At TL 9 a Fire & Movement capital stops being able to build any ships except Adamants unless it is getting chronimium through a trade route. At TL10 all it can build is basic infantry. New players get blindsided by this pretty often. I would suggest that the quantum and post-industrial programs require chronimium to build.

watch tv, do nothing 9 May 2015:

Imperial capitals could also stand to have some special trait or effect to distinguish them from sector capitals, and it should be possible to manually designate a sector capital as the new imperial capital.