Glad you like them, we put a lot of effort for them to not go into the vacuum of space.
And for the gameplay, you have 5 day to "survive" and each day, the cost to travel increase and you need to monitor the expedition module to not lose them and be able to let them collect enought resources to survive the whole journey. And to do so, you need to cancel the expedition module with only one person, as it will not come back.