They'll be too small to clear the way for settlements, but tiny robotic bulldozers may soon be on their way to Mars. Weighing 8 pounds each, the rovers will dig for water or other treasures. Each is equipped with an arm that can scoop Martian soil into an overhead bucket. They're not yet scheduled to fly.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.