The David Stone

Here's an interesting idea for keeping the Earth as an "Asteroid Impact-Free Zone" , keep a sizable stone in orbit and then swing it around to hit an incoming object.

Such an asteroid could then be moved as needed to absorb the impact of any collision that would otherwise hit the Earth. The work of Didier Massonnet and Benoît Meyssignac (Centre National d’Etudes Spatiales, France), the paper argues that an asteroid between 20 and 40 meters in diameter, which the two nickname ‘David’s stone,’ could destroy a much larger incoming object under proper targeting conditions. The problem becomes finding the right asteroid.

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Another benefit is that with the installation of proper equipment, a nearby asteroid could be exploited to produce propellants for manned exploratory missions. Producing fuel like liquid oxygen in such a location would dramatically alter the lifting requirements for long-range flights and could be practical even factoring in travel requirements to retrieve the fuel.

Very cool. I leave it to the communists and libertarians to tell us how to set up utopian governments on such objects.