With NASA planning missions to explore the next planet along, they need to make sure they’ve covered every eventuality. Not just the obvious things, like how much fuel they’ll need or how much radiation an astronaut can be exposed to, but those tricky issues that no one ever wants to be first to bring up – like, what do you do if someone dies or becomes mortally ill en route to Mars? Ethical questions are tricky at the best of times, but when you factor in the isolated and resource-short environment of an interplanetary spacecraft, NASA has a whole philosophical minefield to pick their way through.