It's hard to exaggerate just how successful NASA's Mars Rover program has been. These little vehicles have crawled over different parts of the Martian landscape, sending back invaluable data. But these rovers have some limitations: They move incredibly slowly. In over 2,000 days on Mars, the rover Curiosity has traveled about 11 and a half miles. That's why NASA has approved exploratory funding for an entirely new type of explorer: a swarm of robotic bees controlled by AI.