Deflecting Asteroids

Two new studies look at how we may deflect asteroids that threaten to collide with Earth. A Chinese study suggests using solar sail technology to deliver a probe to an asteroid at the appropriate time. Solar sails, they say, would allow a much higher speed impact than conventional rockets could muster, thus producing a more powerful blow. A European study also suggests slamming a probe into an asteroid at high speed to deflect it into a different orbit, but also proposes a second probe to study the asteroid and monitor the effectiveness of the impactor.

Both studies, therefore, rely on violent measures to accomplish the deflection. That might be necessary if time were short, but if we could act decades before the predicted collision with Earth, that giant solar sail could be attached to the asteroid and slowly change its orbit. In that case, we would be in constant control of the process, and we could ultimately place the asteroid wherever we wanted it.