Ask HN: could we capture and mine Apophis? | Hacker News Reader

Ask HN: could we capture and mine Apophis?

10 pointsduncan_bayne5 comments

The asteroid 99942 Apophis ( http://en.wikipedia.org/wiki/99942_Apophis ) will be passing close to Earth (within geosynchronous orbit) in 2029 and 2036. Its mass is estimated at 2.7x10^10kg.

If it was a typical nickel-iron asteroid, it could contain between 5% to 30% nickel. Assuming the lowest value - 5% - then it would contain US$1,637,550,000 worth of nickel at current prices. The remaining 95% mass in iron would be worth US$8,208,000,000.

I wonder what would be entailed in getting Apophis to enter a low orbit, such that it could be conveniently 'mined'? I imagine something like a first mission in 2029 to set up for the capture, perhaps planting propulsion units etc. Then upon the return in 2036, it could be 'nudged' into the appropriate orbit.

Is this even feasible?

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Its probably not feasible at this time with current technology even if you spent all 10 bil and went for break even.

It is worth remembering though, as we squabble over the scraps on the surface of our planet, that all of its wealth put together is probably insignificant compared to what might be floating around the solar system in easy reach for a sufficiently space-faring species. Lots of nice building materials (that aren't all messed up by oxygen) that don't have to be drug up out of giant gravity wells by chemical rockets.

Even if it were technologically and economically feasible to capture and mine Apophis, the prices you cited wouldn't last; those prices are made considering current supply and demand; if you flood the market with that much nickel or iron, prices will drop incredibly quickly and you'll soon be left with a bum investment.

It's like the proverbial "What if I found a solid gold pyramid under my house?" or whatever.

Not feasible as major governments are busy fighting wars.

It looks like it would take a velocity change of 1 km/s to make it work. For the mass you state, that would be a change of 1.4 * 10^16 joules of kinetic energy, which is 3.2 megatons TNT equivalent. It would take a nuclear reactor to do it quickly enough. It looks like a 50 megawatt reactor would do the trick in about 10 years. That sounds practical.

The tricky part is the propellant for the ion drive. The asteroid probably contains a lot of oxygen that could be extracted, but that takes fancy chemical processing, and the oxygen would tend to corrode the working parts. Shipping an inert gas from Earth would be technically easier, but the launch costs would be impossible unless you develop laser launchers first.

If only we could usefully store antimatter ... use a little of Apophis itself as the reaction mass, energised by antimatter annihilation. That's a way in the future though :-)

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