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It's very easy to avoid asteroid impacts. You do lots of observation, so that you can tell decades in advance, that the asteroid is an imminent threat. Then y

by magduf 7y ago

It's very easy to avoid asteroid impacts. You do lots of observation, so that you can tell decades in advance, that the asteroid is an imminent threat. Then you build spacecraft which intercept it, and use some type of engines (probably ion engines) to slightly change its orbit. You don't need extremely powerful ones, you just need them to operate for a long time. A very small orbital change will result in it completely avoiding the Earth decades later. The key, of course, is being prepared well ahead of time, and looking for these things. We're doing a terrible job of these. If you're a stupid species like the dinosaurs and don't bother to prepare for these things decades in advance, then there's nothing to be done; just let it happen.

jerf 7y ago
Agreed. To elaborate, if you have enough advance warning, you can also dodge all the questions about asteroid composition and what happens if you impact it, etc., by using a gravity tractor: https://en.wikipedia.org/wiki/Gravity_tractor https://en.wikipedia.org/wiki/Gravity_tractor If you can lob one at an asteroid with a multi-year period as it passes near Earth, you can totally, reliably solve the problem for quite cheap. I'd like some significant redundancy in the mission just to be sure, but it wouldn't be that hard, inasmuch as one can say that about anything in space. The situation gets once worse once that ceases to be an option. When you're back to using electromagnetic forces by touching it in some manner, by landing, pushing, exploding, whatever, you've suddenly got a lot more problems.
craftyguy 7y ago
Eh, that all assumes the object has a relatively short orbital period around the Sun. None of that would work for an object with a very long orbital period, which would have a very high velocity in the inner solar system and likely would not be observed until it was already on its way here. Then there are objects which are not in orbit around the Sun, with even higher velocities.
- magduf 7y ago
  >and likely would not be observed until it was already on its way here. That's my whole point: if we were more serious about this, we'd have orbital observation platforms looking for all these objects and keeping track of them all, so that we aren't surprised by anything short of another asteroid from totally outside the solar system like that one a couple years ago.

by magduf 7y ago

jerf 7y ago

Agreed. To elaborate, if you have enough advance warning, you can also dodge all the questions about asteroid composition and what happens if you impact it, etc., by using a gravity tractor: https://en.wikipedia.org/wiki/Gravity_tractor https://en.wikipedia.org/wiki/Gravity_tractor If you can lob one at an asteroid with a multi-year period as it passes near Earth, you can totally, reliably solve the problem for quite cheap. I'd like some significant redundancy in the mission just to be sure, but it wouldn't be that hard, inasmuch as one can say that about anything in space. The situation gets once worse once that ceases to be an option. When you're back to using electromagnetic forces by touching it in some manner, by landing, pushing, exploding, whatever, you've suddenly got a lot more problems.

craftyguy 7y ago

Eh, that all assumes the object has a relatively short orbital period around the Sun. None of that would work for an object with a very long orbital period, which would have a very high velocity in the inner solar system and likely would not be observed until it was already on its way here. Then there are objects which are not in orbit around the Sun, with even higher velocities.

magduf 7y ago
>and likely would not be observed until it was already on its way here. That's my whole point: if we were more serious about this, we'd have orbital observation platforms looking for all these objects and keeping track of them all, so that we aren't surprised by anything short of another asteroid from totally outside the solar system like that one a couple years ago.