If you still intend to see Interstellar unspoiled, maybe think about not reading this post and just clicking ahead to the trailer.
The Martian actually isn’t related to Interstellar at all in any legal sense, but there are unfortunate coincidences – Christopher Nolan’s film featured an uncredited Matt Damon as the lone survivor of a mission to an alien world, driven insane and slightly incompetent (a brilliant astronaut who now has no idea how airlocks work). Now, in this movie, we see how that could have begun, with Damon as…a brilliant astronaut stranded on an alien world, albeit one that’s slightly closer, in Mars.
Thank goodness we already figured out that they key to his survival is to send messages in the dust back in time through five-dimensional space. That’s easy enough to do, right?