A retroreflector does not require aiming nor moving parts, it simply uses geometry to ensure that a lightbeam is always reflected back to its source. Retrorefl

A retroreflector does not require aiming nor moving parts, it simply uses geometry to ensure that a lightbeam is always reflected back to its source. Retroreflectors are cheap to build and well-understood. It is a very interesting idea, the reflectors likely will burn but you could cover the missile with them. You only need to reflect enough to disable/weaken the emitter.