Starcross

Starcross (1982) by Dave Lebling.

As described on the box:

STARCROSS, Infocom's science fiction mind-bender, launches you headlong into the year 2186 and the depths of space. And not without good reason, four you are destined to rendezvous with a gargantuan starship from the outer fringes of the galaxy. Upon docking with the strange craft, you must succeed in gaining entry to its mysterious interior. Once within, you will encounter a microcosm of the galaxy, peopled with both harmful and helpful beings. But the great starship serves a far larger purpose than mere cultural exchange. It bears a challenge that was issued eons ago, from light-years away- and only you can meet it.