Earth is a bit cleaner as most of the heavy dirty industry has moved off planet. Satellite farms handle most of the industrial sector, everything from refining metals and chemicals to pre-assembly finished goods. The only aspect of industry that takes place on earth is final assembly but that is just because it is easier to drop shipments of parts to the surface rather than containers of finished goods.
Stuff gets back into orbit via the mass drivers, be it transports, space ships, or pods of raw materials needed in orbit. There arent many of the mass drivers and the machines run constantly. The rich nations and powers have access to them, the poor nations do not. As a result, the rich nations have easy access to space and the orbital habitats. Their criminals can be sent to penal colonies, and their nasty waste like nuclear waste can be launched into space where it can be stored or launched into the sun.
The habitats and stations dislike the load put on them, each outpost has a quota of work put on it, and it is almost like the industrial revolution with slave like hours, and sometimes dangerous working conditions. There is an expression on the habs 'Keep working, a dozen terrans are depending on your taxes'
Space based warfare is in it's infancy, but there is already a growing concern over control. The habitats and satellites have to be policed for rogue elements, rebellions and revolts. The Martian and Lunar colonies, crowded with excess population from earth and generally composed of criminals, settlers, and others malcontent with society chaff under the rule of their terrestrial super powers. A few unsupervised high end habitats could start building a fleet of warships for one of these disenfranchised sects, which has spurred the terrestrial powers to militarize space and arm their own ships.
Meanwhile the poor nations, struggling with moribund economies, fuel and water shortages and other basic problems watch as the super powers start building space warships, which are even more expensive than their watery counterparts.
Add into the mix: brilliant but eccentric scientific factions, some of which are pushing weapons tech, biotech, and other tech.
limited application energetic armor
cloning tech, to make worker drones, and so that the rich can become functionally immortal
limited ability androids
AI and SI
Early stage energy and beam weapons