For the purposes of this question, assume that a Dyson Array is a collection of discrete solar panels or mirrors orbiting the sun, all of whom share the same orbit and have same velocity.
In practice you probably don't need to be quite so precise about orbits and velocities. You just need to keep them apart and not blocking each other.
Can a civilization similar to us with the same level of technology as present day humanity build a Dyson Array for energy supply, say by using asteroids as raw material by crushing them?
No even close.
We have none of the required tech except in the basic form for some of the least difficult parts.
If not, what would be the minimum amount of technological advancement necessary to be able to build that?
A rough list of things you need to have are :
Self-replicating space craft.
You can't possibly build and launch enough craft on Earth to build such an array/ring. You need to build machines that you can send out into the solar system that will find and collect resources (probably mine asteroids) and be able to construct copies of themselves and send material to where it's needed to build an array of solar collectors. You also need machines that build the machines that build the solar arrays. The chemical science requirements are mind boggling.
And these machines themselves need lots of energy so just finding a source for that energy (more solar collectors probably) would it's own challenge.
We can't do any of these things now, of course. We're hundreds of years away from this, and I mean just the mechanical aspects.
Doing the above implies advances in chemical engineering beyond anything we can achieve now. It involves a machine finding an asteroid, analyzing it's contents and being able to break it up and refine those into required materials. Some of the materials will be quite rare.
Think about the size of a modern chemical plant and then imagine somehow making something even more complex in space from raw materials.
After you gather it and refine it, you then need to make things. These will include computer components and other unknown technologies we don't yet have possibly. So imagine microchip manufacturing being done on this scale in space as part of a vast production system spanning the solar system with millions of machines working cooperatively but without human intervention (or very little, anyway).
The chemical science to do these things is way beyond us. Again hundreds of years perhaps.
Physics and engineering.
Strangely we probably have enough physics to do these things, but there is a world of difference between physics and engineering.
We probably need some advances in propulsion systems but they're something we could probably get to reasonably easily based on current ideas and prototypes.
Engineering is making stuff and maintaining it. That's a whole other ball game. We have essentially no experience of automated engineering in micro-gravity and the conditions in "raw" space. The challenges are huge. Just designing devices that function for extended periods (we could need hundreds of years to build this array) and do so reliably enough to self-repair or at least recycle themselves is daunting. Again we're a long, long way from this kind of goal. We're still finding new ways that machines can fail after years in space. Finding solutions to those problems is equally hard.
AI and computing.
You possibly don't need AI for this, but by the time make the systems you'll probably have AI and need it to control the systems you build. You may even need the AI to do the research for you to enable this, because there is an argument that doing this kind of advanced science is not practical for humans with limited lifespans and relatively slow learning skills. So maybe we need the AI just to do our thinking for us ! By the time you're building a Dyson array you may already to using AI to do a lot of your thinking (and hence control) for you. AI or something close to it may be a requirement for this. And building an AI isn't trivial and although you hear the expression bounced around a lot now, these devices are only prototypes in basic data processing compared to a proper AI that can "think" for itself. That's another thing that is a long way off.
Even without AI you certainly need a lot of processing power and advances in algorithm design and programming to enable engineering on this scale. Bigger and more complex systems. We've already hit practical limits that mean we're moving away from "faster and bigger" to "more efficient, slower and more parallelism", so there are significant issues in all of that. So budget some time and resources for that too.
What for ? Using the energy !
Dyson arrays sound cool, but there are two problems with this idea that are pretty fundamental :
- How do we transmit the power we gather ?
- What do we do with the power anyway ?
This is kind of important. Maybe a K2 civilization has some useful purpose for all this power, but it's just useless to us. We have no idea what could usefully be done with it. Oh, there are wild ideas out there (e.g. build your own black hole), but the reality is that we have no more idea how to use this amount of power than Humphrey Davy would have about using a nuclear power station's output.
So before you start rearranging the entire solar system, you need a purpose !
Transmitting the power is pretty darn important. You have to find a way to move the vast power output from the array to where you can use it. Or we're all moving to the array ? Or something.
And an array like this is also something else : a weapon of vast scale. Anything that could e.g. send vast amounts of power over solar system distances would be absolutely deadly in any hands. Who precisely would have charge of this ? Or we don't transmit the power, in which case we have to use it in situ. which requires building at least an industrial system based around these arrays.
This also raises a problem with that vast swarm of self-replicating semi-autonomous machines. They're potentially just as dangerous in the wrong hands (or some AI's hands !). They'd be designed for micro-gravity, so there's no danger of those machines landing on Earth, but that doesn't mean they (or someone/something controlling them) can't build different machines that can ! And by the time you reach this level of technology you will already have significant numbers of people ling in space - possibly even most people, because self-replicating machines can build vast space stations as well and we'd have cracked 100% recycling by that time.
So we have now a vast and potentially deadly array of machines controlled largely by other machines that can build other machines rocketing around the solar system. Up hands all those who didn't see any Terminator movies and feels safe about this ?
So there are some issues with building a Dyson anything that are only cool if you're a Bond villain.