But KSP does give a false impression.  It is very much a &quot;spheres in a vacuum&quot; approach to orbital physics.  It doesn&#x27;t model many&#x2F;most of the realworld forces.<p>When dealing with the truly minuscule forces such as would be created by lasers aimed at asteroids, one much accommodate all other similarly-sized forces before taking action.  Rocks in space are subject to a force&#x2F;pressure from the sun, a pressure comparable to that from a earthbound laser.  Before trying to deflect, one would have to understand how the sun will be altering the course.  That calculation is not easy and requires details (albedo&#x2F;rotation) that are hard to come by for tiny rocks.  You don&#x27;t want to be countering the force from the sun only to push the rock into an intercept it would otherwise have missed.<p>Vaporization also need not mean destroying the rock.  So long as the vaporized material achieves escape velocity (not hard on an asteroid) vaporizing the surface of an object creates a force, a thrust, which is greater than the pressure directly from the laser.