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Gravitational tractor for towing asteroids

A spacecraft could deflect an Earth-bound asteroid without having to dock to its surface first.


We present a design concept for a spacecraft that can controllably alter the trajectory of an Earth-threatening asteroid by using gravity as a towline. The spacecraft hovers near the asteroid, with its thrusters angled outwards so that the exhaust does not impinge on the surface. This proposed deflection method is insensitive to the structure, surface properties and rotation state of the asteroid.

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Figure 1: Towing geometry of a gravitational tractor.

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Correspondence to Edward T. Lu.

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The authors declare no competing financial interests.

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Lu, E., Love, S. Gravitational tractor for towing asteroids. Nature 438, 177–178 (2005).

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