Planetary Defense at LLNL: How to Protect Earth from Hazardous Asteroids

Asteroids headed for a collision with the Earth, if found early enough, can be acted upon to prevent the potentially devastating consequences of an impact. One technique to divert an asteroid, called kinetic impact, uses a spacecraft to crash into the body at high speeds. This approach delivers the momentum of the spacecraft, while also providing an additional boost of momentum through the production of impact crater ejecta exceeding the asteroid's escape velocity. For cases where the warning time is known well in advance and the asteroid is not too large, it is the preferred deflection mechanism, as described in a 2010 National Research Council report. Dr. Syal will also discusses the nuclear deflection technique, which is a potential option for large asteroids or when there is not enough advance notice for kinetic deflection to work.