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Comment by yongjik | Hacker News Reader

Mankind never had to drill a hole in zero gravity, so I don't think we have such a tool in the first place. Besides, even if we had something like that, I imagine they would be rather heavy. Hauling it all the way to the asteroid will take a lot of fuel and money.

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I would imagine a simple drill bit would do the trick - that action isn't dependent on gravity, and in an enclosed area (the bore) the simple action of the screw should do it. The real trick would be making sure the ejecta doesn't hang around. For small particulates you could use a static field, but larger masses would be harder.

But how are you going to press against the ground without gravity? If you don't press firmly, the drill bit will just scratch the surface instead of boring in. You don't have gravity, and you can't use suction cups (no air!), and I'm skeptical if you can grab on something and hold on to that. (It will require a lot of robotic engineering, and what if the surface is filled with loose gravel?)

Maybe you could fire a rocket in the opposite direction the whole time, but that increases fuel requirement even further.

Any landing on a such a low gravity object object would require some form of anchoring, which you can use to to get the drill started. The Philae lander (was designed to) use its impact velocity to drive ice screws into the surface, before fireing a harpoon. Presumably such a harpoon could give sufficient leverage to get run a drill.

Of course, if you followed the landing, you know that things didn't quiet go as planned, and Philae bounced a few times (and almost escaped the gravity), so this is definitely a difficult problem, but I suspect that once you have a lander that can anchor itself enought to not bounce, you could probably anchor yourself enough to drill.

I was thinking abut this, and it seems to me that the Third Law problem only exists when you're starting the drilling (pressing down) and removing the drill (pulling up). During the actual drilling procedure, there should be a force from the action of the drill bit digging into the rock, and from the stuff being bored away from the drill. Shouldn't there be an equilibrium point where the pressure you're exerting on the drill (pushing you up) matches the force of the drill pulling you down? I feel [1] that higher torque speeds would impact this.

[1] "I feel," "It seems," etc. - I don't have the maths or the physics to back this up beyond intuition and a hasty free body diagram sketch, which admittedly seems to work well-ish for most problems in classical mechanical physics.

Basically, if there's nothing stopping you from spinning then the drill will spin you but with the bit stationary. The fixture holding the drill needs to be secured somehow so that the motor in the drill spins the bit against the surface. On Earth, this is commonly achieved using your feet and friction.

Exactly. There are so many problems with drilling/mining asteroids, its going to be one of the most enormous challenges ever undertaken.

The drill doesn't pull you down. The equilibrium is achieved by (roughly speaking) (the force that the drill bit pushes the ground) = (the force that the ground pushes the drill up) = (the force that you push the drill down) = (the force that the drill pushes you up) = (the force that the Earth pulls you down).

The Earth's gravity on your body enables all this force; without it you need to invent some other way of pushing down the drill.

You need leverage to drill. You have to push down a bit on whatever you are drilling into, which will push you away from it. So, until you drill in enough to get leverage on the target, you've got to either counteract this force, or keep extending your drill arm as you drift away.

Could a very strong laser potentially work for this?

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