[dard]

I work on NEO Surveyor, I replied to the parent comment largely agreeing with you, however I wanted to mention that we do rely on apparent motion for determining if a source is moving (asteroid/comet). However IR is ideal for spotting asteroids for a few different reasons, a big one is that asteroids have a wide range of surface brightness. Think bright concrete to black coal, so in the visible spectrum a 100m light stony asteroid can be just as bright as a 500m coal colored one. It is very difficult to determine size from the brightness alone. However in IR everything is approximately the same temperature (largely proportional to the distance from the sun), so these things all glow in the IR directly proportional to their diameter.