An anonymous reader writes to mention NewScientist is reporting that a small force of robots designed to explode
could help reveal an asteroid's inner structure. This could in turn allow scientists a better understanding of how to divert a rogue asteroid on a collision course with Earth. From the article: "The main spacecraft would stay a few dozen kilometers away, perhaps nudging the probes towards the asteroid using springs. Once on the surface, the protective spherical shell of each probe would open to allow the probe to scan the surface nearby. To reduce complexity and costs, the probes lack solar panels and run on battery power, limiting their lifetime to a few days. But each probe could still cover a lot of ground in that time, as they could be fitted with small thrusters to let them hop across the surface. Eventually the probes could detonate onboard explosives, sacrificing themselves for science one by one. Probes that had not yet detonated would listen for any seismic waves sent rippling out from the explosion, and the main spacecraft could observe the craters left behind. That would tell scientists about the asteroid's strength and internal structure."