This interactive map from the Washington Post is one part of a long-form piece that looks at NASA and the improbable tasks facing the agency. Specifically the piece looks at how NASA wants to get to Mars, but how difficult that is and how an also difficult asteroid mission is as a backup plan.

Really fantastic is about all I can say.
Credit for the piece goes to Joel Achenbach, Alberto Cuadra, Kennedy Elliott, Rebecca Rolfe, and Ricky Carioti.