I've had this problem too. I've also had it throughout the whole of Season 1. But it wasn't as troublesome as in Ice Station Santa. Ice Station Santa is so frustratingly laggy after entering several locations that there's absolutely no fun in playing it.
I do have a bit of a low end computer, but even if I had a better computer, no game should take up a Gig of memory.
Pentium IV 2Ghz
ATi Radeon 9600XT (128mb)
I really hope this issue will get resolved.