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Often after I've mined an asteroid dry I find the security status becomes "low morale". How do I fix this?

I only ever build one resiblock on my asteroids as I've never found any need for more than 250 population. I always build a medical centre, pleasure dome and security centre. The surplus population is around 200 as well. Will hiring a colony supervisor fix this? Because I don't really want to do that as it just seems unnecessary and a waste of money.

Any tips?
Since it refers to security it could be that they feel vulnerable, in a Total War game if you don't have any units garrisoned in your city your citizens get scared. Try a couple of small warships or so and see how they feel knowing there are guns defending them.

Just a rough guess, not played for a few years. By a few I mean almost 15 :D
Good idea, I hadn't thought of that, thanks. I'll give it a shot next time I fire up the game (which could be some time away since GTA V has landed for PC :D).
I played this game when it was new, so my mind can play tricks, but I remember that security centre supports150-200 people max.
Keep security tight, build a pleasure dome and most important of all: KEEP THEM BUSY! If you have a bunch of surplus population (that means non-working pop) they get bored and social unrest will rise. If you have too much surplus population, tear down some resiblocks.