Rather than grittiness, I see realism in how long it takes to walk from point A to point B, or in the equipment and technologies to which the characters have access and can carry, or the odds that they can reasonably face.
Three-Body Problem Review
This is one of those rare hard science fiction books that contrives to both invoke rigorous scientific concepts and offer interesting plot and characters. If some of the more advanced technology revealed at the book’s conclusion seems a bit like magic, well, that’s probably rather the point.
IGC Publishing 