Over the next three and a half years, Project NEOShield (Near Earth Object Shield) will investigate how to prevent impacts by asteroids and comets. Asteroids typically approach Earth at speeds between five and 30 kilometers per second.
Over the next three and a half years,&nbsp;Project NEOShield (Near Earth Object Shield)will investigate how to prevent impacts by asteroids and comets. Asteroids typically approach Earth at speeds of between five and 30 kilometres per second. Thousands of near-Earth objects (NEOs) have been discovered in the past 20 years

Photograph: JPL-Caltech/NASA