Re:Mining asteroids: Going platinum
by daniel-cussen on Friday April 27, 2012 @06:18PM
(#3901268)
> lumps of asteroid aren't exactly known for being aerodynamic, making reentry calculations pretty unreasonable.
As long as you're cutting it, you could make it somewhat aerodynamic. However, you have to remember a lot of the time you want reentry vehicles (or rocks) to be round so that they get down in good condition.
In addition, you don't need to just fire it off into earth; you can attach a computer and small rockets to it so it can subtly and cheaply correct its own course. The energy you would need for this can be arbitrarily small: http://en.wikipedia.org/wiki/Edward_Belbruno
I won't say it can't be done, but there are significant challenges here that you may be underestimating. Not the least of which is the fact that there is no "suck" orbit.
You need quite a bit of energy to make the proper orbital adjustments to aim the rock at a precise spot on earth (rather than some random ocean, somewhere inaccessible, a major city...) and lumps of asteroid aren't exactly known for being aerodynamic, making reentry calculations pretty unreasonable.