It's more common to worry about how to avoid getting too much energy from asteroids, which is what would happen if a big one accidentally smashed into the Earth. The technique that is most often discussed to avoid that is to detect the path of asteroids very early, when they are far from Earth, and then send up a rocket with some device to give them a little push to alter the path enough so it will miss the Earth.
If somebody had a nice controlled way to capture and use the energy of an asteroid as it got close to Earth or another planet, then the same method could be used to steer one to approach the planet instead of miss it.
Jon Thaler, as told to Mike W.
(published on 05/14/2016)
