A "gravity tractor" could deflect an Earth-threatening asteroid if it was deployed when the asteroid was more than one orbit away from the potential impact, according to a new study. If the space rock was found heading straight for Earth, a combination of techniques - including a gravity tractor - might save the day.
The study, carried out by NASA's Jet Propulsion Laboratory in Pasadena, California, shows that the weak gravitational pull of a nearby spacecraft could deflect a hypothetical asteroid 140 metres across, big enough to cause regional devastation if it hit Earth.
"Prior to this study, the gravity tractor deflection technique had been proven in only a conceptual way," says Clark Chapman of the Southwest Research Institute in Boulder, Colorado, who was not involved in the study.
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