Spaces in Space
So the ship has various locations, one of which, in the vein of sci-fi films everywhere is a Cryogenics pod. Originally, in the game the cryopod stopped crew breathing precious oxygen or suffering morale loss and they could walk in or out. This meant that crew could happily spend a lot of game time in cryosleep, rather than hunkering in there during desperate moments, crying and praying or serving out the last few turns of the game there, in the classic tradition of a range of films.
So first off voting rights went out for frozen crew; but the cryotubes remained too easy a choice, walk in on quiet turns, out when things get busy. That meant another solution, so now crew can freeze themselves going in, but need other crew in other locations to unfreeze them. A simple usage of the existing game's mechanics providing another thematically appropriate risk/reward exchange for players. One of the golden rules informing the base of games design for me is, extra choices, harder decisions and deeper interactions are always the aim.