The Asteroid Wars
In The Rock Rats, Ben Bova continues the melodramatic saga that began in The Precipice, with a gold rush to exploit mineral (and other) resources of that vast new frontier the asteroid belt. Independent "rock rat" prospectors trying to get rich out there face not only the bleak hazards of space but ruthless claim-jumping and piracy from hissable bad guy Martin Humphries.
Essef - Once, Dan Radolph was one of the richest men on Earth, but now that the planet is spiralling into environmental disaster, he must look to the wealth of the stars to save the economy. Martin Humphries is also aware of the potential of space-based industry, but he does not care if Earth perishes.