Hugh Pickens writes "A new study at the Jet Propulsion Labs shows that weak gravitational pull of a "gravity tractor" could deflect an Earth-threatening asteroid if it was deployed when the asteroid was at least one orbit away from potential impact with earth. First a spacecraft would be crashed directly into the asteroid, similar to the Deep Impact mission that impacted a comet in 2005. This would provide a big change of direction, but in a less controllable fashion that could push the path of the asteroid into a dangerous keyhole. But then a second spacecraft, the gravity tractor, would come into play, hovering about 150 meters away from the asteroid, to exert a gentle gravitational force, changing the asteroid's velocity by only 0.22 microns per second each day. Over a long enough time, that could steer it away from the keyhole. In the simulation, a simple control system kept the spacecraft in position, and a transponder on the asteroid helped monitor its position and thus determine its trajectory more precisely than would be possible otherwise. "The gravity tractor is a wimp, but it's a precise wimp," said astronaut Jack Schweickart. "It can make very small, precise changes in orbit, and that's what you need to avoid a keyhole.""
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Article is a bit light on concept but I'm not clear why they attempt to use a (potentially risky) crash first when the gravity tractor is a a pre final orbit precaution. The only thing I can really think of is that they're attempting to leave open another full orbits worth of time to try different things.
Brute force first? (Score:1)
Article is a bit light on concept but I'm not clear why they attempt to use a (potentially risky) crash first when the gravity tractor is a a pre final orbit precaution. The only thing I can really think of is that they're attempting to leave open another full orbits worth of time to try different things.