FrankTrollman wrote:Using energy to split Hydrogen out of water and then getting some of the energy back when you recombine it is not a fuel source.
If you're going to be real strict about the terminology then what you're looking for is the term
propellant, rather than
fuel (two very different things but are used interchangeably by most sci-fi terminology).
Without propellant how exactly are you going to move dirt around for processing? Nuclear reactors generate heat (and that heat can be turned to electricity) but for tons of rock to be moved around you need propellant.
And before you go "Ion Drive!" or other similar tech - note that those need propellant too; for instance Ion Drives use various exotic gases (Xenon was used by the Deep Space 1 probe) as propellant and you will eventually run out. Mass drivers are a little better off because they can use just about anything as propellant, but that requires a lot of electromagnetic energy to be produced
and you will need workers to periodically pick up and load rocks unto it (which all but certainly will require the use of propellant). The only propulsion method that doesn't really use propellant are solar sails - but that't not going to be terribly reliable and I'm not really sure how viable it would be for specific purposes.
And splitting water isn't terribly problematic. All you need is a bit of electricity - which you get via solar panels or a nuclear reactor.
Again, the key term is "industrial process". If you want to mine thousands of tons of metal, you need to be prepared to
move thousands of tons of stuff. Even in Zero-G you still need to be able to generate a lot of force to move stuff.
The point of asteroid mining is that there is no "down."
Yeah, but you still need to move the dirt on it and sift for the valuable components. To excavate the metal in Eros for instance would require moving and sifting through more rock than has ever been mined on Earth
too. That's why I keep repeating the industrial process bit. You can't just have 3 guys digging through tens of thousands of tons of rock with some man-portable power tools. They'll basically never finish.
And let's not beat around the bush, some of the M-class asteroids are just reasonably pure metal. 16-Psyche is 181 kilometers thick and apparently simply made out of nickel iron.
Like I said, big universe and there may be a pure Titanium asteroid somewhere.
The issue, as Mechalich noted, is that even a 100% pure Titanium asteroid still needs to be transported to where people actually can use the Titanium. A titanium asteroid in the belt is a curiosity, not a resource, until it's in the hands of people who can turn that metal into useful things.
Indeed, I would note that for reasonably "pure" asteroids it may be wiser to just attach an engine on it (with an efficient drive that uses low amounts of propellant) and to drop it down the Earth's surface so long as we are reasonably sure we can crash it into an uninhabited area and it won't trigger big environmental problems. Having a 10 ton Titanium asteroid crash into Siberia and have it "mined" on Earth would probably be cheaper than sending a crew into space to mine it bit by bit.
In particular, I would note that this is an option that's totally encouraged in
Terraforming Mars. Rather than mine asteroids and send stuff down to Mars, players are encouraged to drop entire asteroids into the Martian surface to both increase available metals or water on the surface and to trigger increases in temperature. The most extreme case being attaching a bunch of engines on Deimos and dropping one of Mar's moons unto the planet itself.
In short, the game turns you into a Gundam villain. Except your actions are totally legal and profitable.