Better ways to do it
I like the idea of using the asteroid or comets own mass as propellant, by hitting the potential impactor with lasers to start the jet reaction - we have the lasers and nuclear electric generators in hand, as well as the ion engines to get there -
vasimir wil require some new technology, and then there's the problem of hard physical docking - you have to have another full multi-engine system on the craft -
The other way is with old faithful, large nuclear explosive charges, but the laser diversion idea that the CAPS team down at Langley developed looks best to me -
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