I like the idea of space ship roleplay, and I love Alien, but I don't know how well this would work if everyone knew the scenario in advance. It's rarely particularly fun to roleplay staged surprise about a thing you understand completely OOC, and in this event everyone would be pretending not know a lot.
OOC, everyone knows what the alien artifact would be, and everyone knows the exact characteristics of the egg, facehugger, alien, plus the malicious side of Weyland Yutani. If you've ever tried to get people to leave camp in the Outlands when they know there's a combine patrol, you know misery you'll inflict when you tell people to stand over by *that* egg because it's safe for sure. In the case of The Thing, at least, there's lots of interpersonal drama since anyone could be it.
Personally, I think it would be cool to just have a spaceship RP where the players don't know too much beyond their particular roles on the ship. Better still if it isn't set in an established fictional universe where we know the rules. Maybe there'll be an alien, but equally there could be a traitor, or a boarding party, or malfunctioning AI. I like to be kept in suspense.