R. J. MacReady

An army chopper pilot during Vietnam, something during the Lieutenant's tour caused him to inwardly snap. From the Tet Offensive to Mai Lai or worse, MacReady came home changed. From his anti-social attitude one can surmise he wasn't given a heroe's welcome either. It's possible he fought against unknowledgable peers, family and community.
Now brooding behind alcohol and solitude, he signed up for a position as a helicopter pilot stationed at the American Antarctic research station Outpost 31.