The marketing for The Martian has been great so far, and this video is no exception. It gives us some background and sets the tone of the movie without giving away any spoilers. It also feels like an episode of Cosmos, but that's just icing on the cake.
Funny though, that we don't have a good way of describing an advertisement like this (calling it a "Viral Clip" is stupid). Maybe if more movies start doing this sort of thing we'll come up a better name for them.