What kinds of engineers are likely to be in demand on a future Mars colony?

6 days ago

If humans succeed in setting up a colony on Mars in the future, as Elon Musk hopes to do, presumably they'll need a lot of engineers.

What engineering specialisms are likely to be especially in demand in that environment?

Put another way: if I wanted to maximise my chances of getting a ticket to Mars, what would be a good niche to start studying today?