FM: SLDF p. 110 has some info - the 7th Fleet’s resupply base is in the asteroid belt. There is an emergency supply cache at the Nagayan Mountain Castle Brian. There is a supply depot in Freeport.
Handbook: House Marik p. 70 profiles Helm as having been an agricultural colony. So, it is unlikely there was orbital industry. It has no satellites, and there are at least three other planets in the system, leaving Helm as the 4th.