The temporary stats will range up and down due to wounds and experience gained, along with other assorted reasons, but the potential stats are a permanent indication of how strong, wise, etc. that a character might ultimately become. Players roll on a table each time they gain a level of experience to find out how much their temporary stats have improved. Most of the Spacemaster system is identical to its fantasy counterpart. There are professions, which translate roughly into classes, and training packages, which are equivalent to kits. Characters go up in levels and have concussion hit points that determine how much damage they can take.
Critical hits are still the usual cause of death however.
The main difference between Spacemaster and Rolemaster is the Psychic Powers. Instead of Psion lists like the old Spacemaster used, the new system uses the skill categories with specific skills falling underneath those headings. A psychic with Psychokinesis for example, may have skill levels in Kinetic Bolt or Telekinesis, but his overall power level will be determined by how many ranks he has in Psychokinesis. This method works well but cuts down on the number of Powers that players have access to. The other big difference between this edition of Spacemaster and the old one is the Privateers universe.