China and the US have reportedly both used kinetic kill vehicles to destroy satellites. This strikes me as rather inefficient, however.
It's well known that micrometeoroids pose a risk to satellites, so satellites are generally hardened against such impacts. There's a limit to how well they can be hardened, though; it seems like an object with a diameter of 10 to 20 cm impacting the core of a satellite should be enough to destroy it. An artificial sphere of this size made out of steel would weigh about 30 kg.
By contrast, a kinetic kill vehicle must have the same kinetic energy as the satellite it intends to destroy. If my understanding of orbital mechanics is correct, the speeds of the two objects is likely to be equal, so the kinetic kill vehicle must have a similar mass to the satellite it intends to destroy. In the case of the semi-recent Chinese launch, that's about 750 kg.
I understand that kinetic kill vehicles are able to tear apart the satellites they impact, and a tiny object putting a hole through a satellite would at best disable it, and could not accomplish the stated goals of either the American or Chinese weapons. That being said, have such small weapons ever been seriously considered? It seems like the significantly lower mass of such a system would be significantly cheaper and easier to launch.