It doesn't have to be a big, rigid, monolithic thing. It could be thousands of satellites (not at the same altitude...). Sort of like a flock of birds. With vast, incredibly thin gossamer wings. And the goal wouldn't be to completely occlude the sun, but to reduce by a small percentage the radiation that reaches the ground.
Enormous solar sails essentially.
We're also talking about an essentially 2D object in space. Sure, there's depth to it, but the depth is irrelevant compared to it's height and width. And there should be absolutely
no concern about the gravity of such a structure. Gravity is a function of
density and overall mass. A light-weight object with low density (such as a simple skeletal frame to support it and keep it in place while the majority of its body is spread out over a plane) would exert negligible gravity. Even similarly massive space structures like
space colonies would exert an immeasurably tiny amount of gravity.
Even if you use a "
flock of birds" concept, all of this remains the same.
And [MENTION=6801328]Elfcrusher[/MENTION] none of what I wrote is to
disagree with you, but all in support of your statements. The science of space structures is one of my obnoxious hobbies.
In the not so distant future....
- A blanket of satellites encircles the earth with rotatable solar panels that can be used like a colossal venetian blind to shield the ground from solar radiation, with the (ostensible) purpose of mitigating global warming.
- That didn't work out quite as well as was hoped.
- Many of those who can afford to choose to live in orbit.
- On the positive side, the vast majority of the generated power goes to running server farms, in orbit, that can barely keep up with all the block chain processing that humanity requires.
- Which is a lot of processing, because countless fortunes have been made from mining asteroids. Even the miners, who agree to live on asteroids for one year (not counting transit time) earn trillions (millions in today's dollars). And nobody wants to pay taxes.
I'm imagining a kind of Shadowrun meets Paranoia meets Firefly kind of thing, if written as a collaboration between Neal Stephenson, William Gibson, and Arthur C. Clarke.
- What are the features/factions/conflicts in this world?
- What's happening on the Moon? On Mars? How about the moons of Jupiter and Saturn? (I'm betting on at least one 'estate' on Europa. Which raises the question of whether there is life there...)
- Does all the wealth mean prosperity for all? Or greater disparity than ever?
- What technologies have finally been invented/perfected/adopted? Fusion energy generation? Orbital elevators? Designer babies? Brain-Computer Interfaces? Nanotech Manufacturing?
- What impact do the environment/technology (e.g., cut-resistant textiles and the Very Bad Consequences of bullet holes in a vacuum) have on combat?
So some more specific thoughts, in order:
Your main divisions are going to be economic and location. The Moon lacks any real useful resources and is terrible for constructing...well anything.
The moon would likely have underground structures.
What exactly is going on there is likely power generation and manufacturing. You import highly toxic elements from the various parts of the solar system and turn the moon into a giant friggen nuclear power plant. Who cares where the waste goes, the moon is devoid of life and unable to support it. Meanwhile you use that ridiculous amount of power to build...everything.
Mars has a perfected system of the "satellite umbrella" that Earth lacks (Earth's was the prototype). Mars requires this device in order to protect its relatively weak atmosphere from solar radiation.
Earth is of course, jelly. But Earth also has the giant space battery in orbit. Mars is Jelly. Phobos/Daemos just isn't cutting it.
Mars is fairly developed and suitably teraformed, though the atmosphere is still weak and without the Mars Solar Umbrella those teraforming efforts would be undone quickly. Mars relies on panels produced on the Moon to expand and repair their Solar Umbrella. There is some push to simply build a dyson sphere around the planet, most people think it's silly. (hint: the leadership says it's silly but they're actually working on it)
Since the Earth Solar Umbrella largely failed, Earth is being strip-mined, conditions are worsening 100 times faster than they were before. Raw materials are strip-mined from the earth, shipped to the Moon for production and refinement and then sold to space-colonists who use the materials to construct more space colonies. People on the Earth see zero benefits. Queue promises that "We'll fix the Earth umbrella!" *spoiler: it doesn't happen!*
The Moons of Saturn and Jupiter are far away and to some extent the "unexplored frontier". Colonization efforts are slow. Getting people out there is hard, we don't have warp drive yet, but we do have cryo-freezing. Teraforming efforts are equally slow. Most colonists still rely on domes, which are of course, produced on the Moon and
literally the colony ships sent out there.
The wealthy live in space-colony sized ships that can travel between planets. If they tire of the conditions around Earth, they go to Mars. If they tire of Mars, they can go to the "Ring Worlds". Or simply fly off into the depths of space. These colony ships were made by literally slicing off the prettier parts of Earth and shipping them into space. So yeah, Earth sucks now.
Speaking of mining, dragging asteroids from the Belt back to Earth or Mars is silly. Ceres acts as a base of operations for Belt mining. The Belt is a harsh mistress but apparently full of valuable materials even the Earth lacks. Want to get rich quick? Try your luck on the Belt! The Belt is of course, massive and people tend to go "missing", as do their fortunes, never to be seen again.
As for relative technology levels: Earth has regressed. Mars is progressing slowly, the Ring World colonies have nothing special. The majority of the advanced technology exists on the mobile colonies of the wealthy. From nano-machines to AI and machine-brain interfaces. The further from a physical world you get, the more advanced technology gets. The Moon provides some degree of R&D for these things and the Earth often acts as a testing ground for munitions. Surprise: the Mars Solar Shield acts as a
real shield in case the Earth-Sphere gets uppity.
Hmmm...fairly dystopian. But then, that's probably what you would get when you cross Clarke, Firefly and Shadowrun. Corporate overlords, a wasted Earth, a half-baked Mars, and people taking insane risks to get rich...with a dash of hope for something better on the fringes.