re: #233 wheat-dogg

For a spacecraft to have a gravitational effect, it would need to be Death Star-sized. But you could use the thrust of the spacecraft to alter the trajectory of the asteroid enough to miss hitting the Earth.

That is, if we had that kind of spacecraft just sitting around doing nothing.

Gravity Tractor. My skepticism is towards our knowing the orbit of a threatening object precisely enough to determine it would impact Earth that far in advance, or that any tiny change we could make would do more good than harm.