|We are seeing a new concept in two new missiles intended for missile defense, the SM-3 and the THAAD. These missiles have no warhead in the conventional sense. Instead of an explosive warhead, they use a kinetic hit-to-kill warhead.
This does pose certain advantages over the HE warhead. Some warheads can carry 1,000 kg or more of high explosives. And this multiplies dramatically the amount of fuel required to deliver the weapon. This requires that the missile be slow, short-ranged, or very big. Whereas the sensors and electronics of a kinetic HTK warhead are relatively small and light. This means you can get a lot speed and range in a relatively small missile.
Warhead: 137lbs Weight: 1,357lbs Range: >46km Speed: Mach 2+
Warhead: 137lbs Weight: 1,558lbs Range: >80km Speed:Mach 3+
Warhead: HTK Weight: 3,300lbs Range: >247km Speed:Mach 29+
Granted, the weight of the vehicle doubled, but look at what happened to the range and velocity.
As for damage, this would certainly destroy any satellite, missile or aircraft it hit. The kinetic energy has been quoted as being 130 megajoules (the equivalent of a 10-ton truck crashing into something at 600mph).
While this specific missile would have limited applications in other areas, the concept is certainly a viable one. Suppose, for example, an anti-ship version were made. It could conceivably be enough energy to split a ship in half. Or an anti-tank version? Studies have been done on kinetic-energy tank weapons. While they did not penetrate the armor on an M-1A2 talk, it did kill the tank by creating such a violent impact that it killed the crew, destroyed the electronics and everything mechanical. (Think of it as scrambling an egg without breaking the shell.)
Kinetic kill weapons have another benefit: less chance of a catastrophic magazine hit on vehicles that carry them because you don't have HE warheads.