Actually, if we're talking about our own asteroid belt, Kuiper Belt and Oort Cloud, there's a lot of empty space between asteroids, cometoids, dwarf planets et al in those three areas. So approach navigation wouldn't be a problem, unless you were dealing with a situation where an asteroid had one or more satellites in orbit (which is sometimes the case).

The Jovian and other planetary trojan asteroid clusters are still some distance apart. However, given the possibility that if they formed alongside the planets they're in synchrony with, there might be more useful raw materials present there, I suspect one relevant skill might be proficiency in dealing with high-radiation environments, particularly if we're talking about Jupiter or Saturn Trojans.

Orbital navigation around a small celestial object might be a useful attribute of asteroid mining, as might knowing how to read spectrographic analysis and other instrumentation to ascertain the concentration of whatever trace elements you're looking for, so geological proficiency would be a relevant skill.

So might knowledge of chemistry and engineering in low gravity environments as well as mining operation experience offworld.

Things might be easier on the larger planetary satellites, asteroids or dwarf planets from this perspective, given their greater mass and density. I suspect that they would probably be the first extractive colonies ventured for that reason.

Most asteroid mining SF takes place in the intermediate range asteroid belt between Mars and Jupiter, given we know less about the Kuiper Belt and Oort Cloud due to their distance and preliminary exploration stages as yet. If the NASA New Horizons mission can locate new mission targets out beyond Neptune, we might have a better idea.

Incidentally, there'd probably be robot mining operations established out there before humans travelled out there. I can foresee a period of risk assessment before regulatory agencies allowed human access to asteroid mining. So robotics competency might also be a useful skill to have.

If we're talking alien asteroids, it's possible some dwarf planet sized asteroids might have some primitive life, possibly parasitic and/or microbial, so we're talking the size of Ceres, Vesta, Juno and Pallas here.

As for weaponising the above skills, much would depend on how skilled your opponent might be in corresponding areas. 

Sorry, Doc, I was in a hurry this morning. I suspect you remember what coffee break times are like!

This takes place in the Rao system, in the orbital belt filled with the rubble of the destroyed planet Krypton. As in practically any system of captured asteroids, the volume is mostly empty space - even in the 'thickest' parts of the belt. Unlike our own asteroid belt, this one has existed less than 100 years and while it is slowly spreading out to be less dense, in certain areas of the belt the density is higher. And because a lot of momentum-absorbing collisions between the various chunks have not yet occurred there is probably a wider range of velocity distribution than in a more long-term asteroid belt. There are chunks in this belt that are probably as large as some of the smaller moons in our own system, a lot of 'mountain-sized' chunks, down to a LOT of dust that hasn't yet been swept up by the larger stuff.

I see the profession of prospector as more of a 'full time solitary pilot' with only rare social interactions rather than the more rugged, bar-fighting-every-time-he-roars-into_town on his barely broken wild stallion kind of person. It is a LOT more difficult to set up saloons and cat houses in space with airlocks and the constant need to bring EVERYTHING in, including air and water, than it was in the wild west. So I don't think brawling is necessarily a prospector skill set. Being proficient in hand weapons that work in vacuum seems like a probable skill (lasers or hand-held missile launchers to destroy small, unexpected meteors just about to smash your helmet to smithereens, for example) and using ship mounted weapons too - both to protect the ship from collisions and pirates.

And estimating trajectories, both from the control seat and when in a spacesuit outside. And yes, chemistry and some construction techniques, perhaps handling explosives, general rocket repair skills and familiarity with tools, cooking and housekeeping. Some prospectors might set up a still in the spare cargo compartment, or even brew their own drugs. Probably many of them are good programmers.

None of that, other than the trajectory estimation and the familiarity with hand weapons, seems to me to be useful in fighting. I'm looking for some awesome secret weapon that nobody (other than us!! ) will ever expect.

Thanks all so far!

Unfortunately, our own solar system has no known super-terrestroid planets, so we can't see for ourselves what happens when a super-earth like Krypton explodes. We know that some of its ejecta fell into Rao, much as Wegthor's fragments did when Jax-Ur's carelessness destroyed that satellite, and probably advanced the imminent destruction of Krypton due to the ensuing electromagnetic or gravitational effects.

Some of the fragments might have hit Thoron, although it seems as an advanced civilisation, it might have had spectrographic early warning that Krypton's core was volatile or unstable, and had orbital particle beam or laser installations either in thoronostationary orbit or on its satellites ready to zap any incoming debris. I'm assuming that as an advanced civilisation, Thoron would have also been able to protect itself against the electromagnetic pulse that would have resulted from the nuclear chain reaction that obliterated Krypton.

We know that some of the kryptonite was scattered into interstellar space, possibly by the space warp Kal-L's rocket made when it escaped from Rao's solar system. As for its planetary debris, it seems that the Jewel Mountains and Gold Volcano were volatilised and transformed into gold and jewel kryptonite rather than green kryptonite, and magno-kryptonite seems to be a sub-variety of green kryptonite caused when the Magnetic Mountains were destroyed. However, for some reason, Krypton's Fire Falls were wholly preserved almost intact- Supergirl bathed in them at one point with no ill effects, so it cannot be composed of green kryptonite. The above suggests that the explosion of Krypton produced fragments that had differential effects given their pre-detonation kryptological chemical and elemental composition in some cases. Most of it became green kryptonite, but clearly not all of it.

Therefore, I may have an inferred motive for an asteroid miner prospecting Krypton's ruins. Let's say that there are useful post-detonation kryptonite variants that resulted from the explosion and our prospector is trying to get her or his hands on those. As for competing prospectors, perhaps they were both in the Thoronian interplanetary armed forces and acquired useful space-based combat skills, whether suit to suit or within small, mobile exploratory spacecraft.

Ah. If white and jewel kryptonite-two have analogous effects to their kryptonite-one counterparts, then there could be good reason for asteroid prospecting in the K Belt. Jewel kryptonite-two might have applications in telepathic receptivity and psionic criminal apprehension, if Thoron has any criminal telepaths. If white K-two operates analogously to its K-one counterpart, then it could be useful as defoliant if Thoron has problems with predatory vegetation (say, something like John Wyndham's Triffids or Anne MacCaffrey's Pern "threads"). One advantage of having a scantily detailed world is that you can embellish and detail at will.

You could make your protagonist a xenobiologist, which could be useful in deducing possible vulnerabilities when it came to alien protagonists. Particularly if Thoron has comparative expertise in the life sciences to Daxam in Universe-One, which was said to be highly advanced.