Averting Armageddon, with ROI

Mike,

Was just reading your "Averting Armageddon, with ROI" article posted to
the SSI e-mail list.

Years ago, I too contemplated using modular mass drivers to propel an
asteroid using it's own regolith material as the reaction mass. I think
it would require a nuclear power sources to at least boot-strap the mass
driver units, as solar would be too cumbersome and underpowered to be
useful initially.

As opposed to the mass driver tractor concept, I suggest strategically
landing 3 mass driver units on the spinning asteroid at the tangent
points of an imaginary equal angle 3 sided pyramid intersecting with the
surface of the asteroid. The mass drivers would be oriented radially
opposing each other in line with the direction of the legs of that
pyramid along the asteroid surface.

By a coordinated application of each of the mass drivers (requires
semi-reliable communications between the units), the asteroid could
slowly be de-spun and then propelled and steered to the desired destination.

It would work similarly to the tractor concept, but doesn't require a
massive structure and capture bag.

I would argue that a redundant 4th mass driver unit located at a point
equidistant to the other 3 on the opposite side of the asteroid could
help despin and steer the asteroid quicker, but it would need to rotate.

If the mass drivers were telescopic and the segments supported on
pivoting wheels (think landing gear crossed with lunar buggy wire
wheels), they could be deployed or re-deployed as needed in whichever
direction was optimum (presuming that no significant obstructions
blocked the deployment or exhaust path. The base end would obviously
require some sort of anchor/drill mechanism to react against the mass
driver's resulting thrust.

These are just some ideas that I came up with building on my previous
concept and what was discussed in your article. Feel free to share with
researchers working on the problem.

Mark Reiff markreiff@...