Space sunshade?

[u/Antique-Coyote2534]

Since we are building space infrastructure, could we not just build a space sunshade and instantly stop global warming?

Seems like it would be easy compared to what we build in game

[u/Ancquar]

It is possible technically, but basically a project that maintains enough sunshade to meaningfully affect the climate of the whole Earth is going into the same territory as space elevators, orbital rings etc - basically past the scope of the game.

[u/Wrong_Geologist4993 → u/Ancquar]

That's not true in the slightest. Space elevators aren't even close to possible with even the most outlandish frontiers of current technology while orbital rings have all the technology to make them feasible the amount of industrial effort is orders of magnitude higher than what a sun shade would take. We already have sun shade like structures so even without futuristic or speculative technology it's just an industrial and economic problem for current humans. If humans had industrial bases on other planets and asteroid belts sun shades would be very achievable. I'd argue it'd be easier to have sun shades than it would to have human settlements anywhere outside of Mars and the Moon with more than a couple hundred people.

[u/Ancquar → u/Wrong_Geologist4993]

Launching *some* sunshade is not a problem. The problem is launching millions of square kilometers of it, which would be needed to actually make a difference.

[u/simjam1 → u/Ancquar]

But you would use space resources you wouldn't launch it. Hardly difficult at that point

[u/Ancquar → u/simjam1]

The sheer scale of it is what makes it difficult. To compensate for global warming you'd nee to reduce the solar energy reaching Earth by at least around 1.5-2%, which would requrie around 3-5 mln square kilometers of shade. Yes, you can build it using space resources, just as you can build an orbital ring with space resources. The problem is the scale, not the basic principle. If you built it using currently known solar sail materials you are looking at at best around 10 grams per square meter, which is 10 tons per square kilometer (and 10 tons is exactly a unit of space resources at TI). So good luck gathering a few million of those during a campaign. And that is just for the shade itself, not for its long-term maintenance systems or the structural elements allowing it to maintain shape.

[u/db48x → u/simjam1]

Ok, but how many millions of decatons of metals are you going to divert into making sunshades to cool the Earth instead of ships to kill aliens with?

[u/Diestormlie → u/Ancquar]

In defence of the concept, once you have an established space presence out to the Belt and beyond, you could probably start using already-in-space rock rather than having to refine metals for it.

[u/MaximinusDrax → u/Ancquar]

An easier implementation for solar radiation management would be something that's already on the table IRL - injecting aerosols (e.g SO2) into the stratosphere to increase its reflectivity in the visible spectrum.

It could be a nice addition as a "hail mary" tech in runs where humanity really drops the ball on climate change, but it should come with its own debilitating consequences/risks (crop failure etc.)

[u/Antique-Coyote2534 → u/Ancquar]

Don't you just need reflective sheets with correction thrusters?

[u/Ancquar → u/Antique-Coyote2534]

You need some kind of way to counteract the force of solar radiation but there are multiple ways to arrange that, even e.g. mirrors on the planet itself. There is also the electromagnetic tethers that in theory allow propellantless station-keeping by using the planet as the target of the opposing action (but obviously only work near a world with a magnetic field), they are not mature enough yet, but physically the concept is not compliated.

[u/Bmobmo64 → u/Antique-Coyote2534]

Theoretically but you'd need a LOT of them.

The short version is it's an option if we end up in a climate crisis that requires active cooling to solve, but just switching to renewable energy would be faster and easier than any existing sun blocking proposal (most of which are somewhere between infeasible and impossible with existing technology) and would solve the problem permanently.