The two dominant cultures in the verse are Anglo (well, American, really) and Chinese. Everyone (pretty much) speaks English, but everyone swears in Chinese (a mixture of Cantonese and Mandarin, apparently).
If you want to say something's good you can call it 'Shiny.'
'I like that gun, it's shiny' or 'It's good to see your shiny faces.'
If you want to say god damn, which you do a lot in western space games, say 'gorram.'
'Get off my gorram ship!' or 'Gorramit, I cut myself shaving, again.'
If it's bad call it 'leh-seh' as in garbage or fei-oo, which is 'junk.'
'Your ship is a pile of leh-seh!'
Or if it's more shit than garbage, 'go she'.
'Your ship is a pile of go-she!'
Really? is 'Shi ma?'
Sonuvabitch is 'hun dan' as in:
'You saved his gorram life. And he still takes the cargo. Hun dan.'
Screw you is 'Chi ni de'
But mainly, it works to just say a load of nonsense chinese sounding crap, and we'll just guess what you're supposed to be saying. Just for the record here's some of the stuff from the show:
'Ta ma de hun dan.'
Mother-fucking son of a bitch
'Shun-sheng duh gao-wahn'
Holy testical Tuesday
'Gen houzi bi diou shi'
Engage in a feces-hurling contest with a monkey
'Liu kou shui de biaozi he houzi de erzi'
Son of a drooling whore and a monkey
'Tai-kong suo-yo duh shing-chiou doh sai-jin wuh dhu pee-goo'
Stuff all the planets in the universe into my ass