Dyson Sphere thread

[Creator223]

Hi!This is the thread to discuss, how the Dyson sphere can be built, what difficulties are in doing so, and so on.

 

[Wolfshadw]

Well, if you could somehow collapse the Oort cloud down from 100,000 AU to around 3 AU, there might be enough material to fully encapsulate the Sun. Other than that, there isn't enough raw material to create it.

-Wolf sends

 

[Creator223]

hmm, well it is not required to encapsulate it

 

[Creator223]

you can make a 'horde' of mirrors instead

 

[Creator223]

It is called 'Dyson swarm'
And for its construction, the resources of Mercury are enough.

 

[Catastrophe]

Wiki Dyson Sphere

Quote
A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output. The concept is a thought experiment that attempts to explain how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet's resources alone. Only a tiny fraction of a star's energy emissions reaches the surface of any orbiting planet. Building structures encircling a star would enable a civilization to harvest far more energy.
Quote

My emphasis.

Cat

 

[Wolfshadw]

Also:

How to Build a Dyson Swarm

To anyone infatuated with science fiction, a Dyson sphere might be the Holy Grail.

www.space.com

There is a clear distinction between a "sphere" and a "swarm".

-Wolf sends

 

[Catastrophe]

Thank you. I was not aware of that.

However, (Wiki: Dyson Sphere v swarm):

Quote
Disadvantages resulting from the nature of orbital mechanics would make the arrangement of the orbits of the swarm extremely complex.
. . . . . . . . .
Another potential problem is that the increasing loss of orbital stability when adding more elements increases the probability of orbital perturbations.
Quote

I found this interesting.

Cat

 

[Wolfshadw]

Thank you. I was not aware of that.

Heh... Neither was I until I decided to delve a little deeper!

Disadvantages resulting from the nature of orbital mechanics would make the arrangement of the orbits of the swarm extremely complex.
. . . . . . . . .
Another potential problem is that the increasing loss of orbital stability when adding more elements increases the probability of orbital perturbations.

Agreed.

We'd need to first put in place some sort of Solar Positioning System, similar to GPS, but for solar orbit. The collectors would need to use this to maintain alignment and position. What good is a collector if it cannot deliver the power it's collected? Also, as more elements are added to the structure, the SPS would assist in the repositioning, provided those elements have some sort of thrust/vectoring capability.

The big problem comes in when these thrust/vectoring capabilities fail. Assuming you have a 10x10 element structure. What do you do when element A6 fails? Could we possibly eject it and send in a replacement or would we have to shut down other elements to maintain attitude? What if we...

I'll stop there. Otherwise I'd could go on for pages and pages.

-Wolf sends

 

[Helio]

I've never given this topic much thought, but wouldn't a large plate at L1 be the most sensible first step? I assume it would be somewhat easy to hold in place, thus it would provide some shadowing effects.

My rough calculations show a 2550 km dia. disk at L1 would reduce solar radiation by 1%, effectively. [It blocks the central part of the solar disk that radiates at 2.6x that of the limb.]

 

[Creator223]

oof, I thought it is the same

 

[Creator223]

You guys are so professional

 

[Catastrophe]

Helio, mate, are we not looking at Dyson "systems" capturing stellar radiation? I can't see any Lagrange Point making much difference. As you point out, L1 partially "eclipses", whilst L2 is eclipsed by the planet?

Cat

 

[Helio]

Helio, mate, are we not looking at Dyson "systems" capturing stellar radiation? I can't see any Lagrange Point making much difference. As you point out, L1 partially "eclipses", whilst L2 is eclipsed by the planet?

Well, I was trying to follow the flow.... sphere --> swarm --> plate(?).

Your point about orbital stability for a swarm is important, but an L1 object, even large, might offer a better solution. A 1% change in solar radiation could make a difference over time. If necessary, due to GW, then a much larger plate might work. I'm only guessing, admittedly.

 

[Catastrophe]

Helio,
Sorry, you are losing me. A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its power output. Langrangian points are the constant-pattern solutions of the restricted three-body problem. For example, . . . two massive bodies in orbits around their common barycenter, (Wiki). My emphasis.

The purpose of a Dyson sphere is to provide power from the central star to the encompassed planet. The two Lagrange Points L1 and L2 are in line star - L1 - planet - L2 (we can involve L3-5 if you like). Depending on relative size, L1 and L2 either eclipse or are eclipsed by the other entity. This seem to be the opposite of providing power to the planet.

I may be missing something, but I find it difficult to reconcile these two concepts.

With best wishes,

Cat

 

[Creator223]

The Dyson sphere requires LOTS of energy to build.Because until it is done, it won't provide energy, it will be practically impossible to build a 'sphere'.

 

[Creator223]

That's why the swarm is a lot better as 1 mirror gives the energy to build the other one.If we use mirrors+catapulting system to send them around the Sun it will not very energy-consuming.Another problem is that they ALL have to follow one vector of their orbit, or they collide into each other.

 

[Catastrophe]

Has anyone done an estimate of materials required and energy consumed and cost to get to the very first stage? Where is it shown that a first mirror provides "the energy to build the other one" and this must include, of course, manufacture including energy and raw materials (which are?)?

Just asking, as there are so many pie in the sky proposals bandied around without any practical basis.

Cat

 

[Creator223]

Where is it shown that a first mirror provides "the energy to build the other one" and this must include, of course, manufacture including energy and raw materials (which are?)?

Well, I mean that fabrics and catapult for mirrors can work on electrical energy.Of course 1 mirror might not be enough, but several can already reflect sunlight to the collector, which can give energy to Mercury.Raw materials can be harvested there.

 

[Catastrophe]

"Raw materials can be harvested there"

Can you please be specific as to what the raw materials are, and how they are produced.
I am particularly interested to know whether aluminium is needed.

Cat

 

[Creator223]

Well, I'm not a professional, but it is assumed(Stephen L. Gillett. Mining the Moon. Analog, Nov. 1983 ) , that on Mercury there are huge deposits of iron ore.Which can be used for the production of mirrors.Also there might be deposits of Helium-3 in Mercury's ground, which, cannot be used anyhow for now.
(Info taken from wikipedia)

 

[Atlan0001]

A Dyson's Sphere is far too big, far too singularly dicey and vulnerable, taking far too long to construct, concentrating far too much species' attention (far too expensive using far too much species energy), to be built by any species not gone completely mad (insane) as a species. Far better small islanded colony city-states, islanded stations, and specialized function facilities, spread widely in countless numbers, countless ships and boats, and countless lanes of traffic. Far better inventiveness and discoveries in countless chances, countless possibilities of evolutions, revolutions, and change (up to the invented or discovered [possible] means of going interstellar). Whatever of microbes, terrorists, or alien invaders (animate and/or inanimate) , could not wipe out the whole of the life at one swipe. A Dyson's Sphere does not deal in survivability of life, thus does not deal in prosperity of life either. Exactly the opposite. It would be the largest [constructed] coffin in any galaxy.

 

[Catastrophe]

Well, I'm not a professional, but it is assumed(Stephen L. Gillett. Mining the Moon. Analog, Nov. 1983 ) , that on Mercury there are huge deposits of iron ore.Which can be used for the production of mirrors.Also there might be deposits of Helium-3 in Mercury's ground, which, cannot be used anyhow for now.
(Info taken from wikipedia)

There is plenty of iron in Mercury's core, which is inaccessible. Any near the surface must be quarried as ore and then purified.
Do you do this on Mercury or transport it elsewhere for refining?
Somewhere you have to built the ore refining plant and provide it with energy.

Where?

Cat

 

[Creator223]

Do you do this on Mercury or transport it elsewhere for refining?
Somewhere you have to built the ore refining plant and provide it with energy.

Where?

Same on Mercury.There are LOTS of solar energy.As Sun is close and Mercury's atmosphere is very rarified it is the best solution for getting energy.

 

[Catastrophe]

"During the day, temperatures on Mercury's surface can reach 800 degrees Fahrenheit (430 degrees Celsius). Because the planet has no atmosphere to retain that heat, nighttime temperatures on the surface can drop to minus 290 degrees Fahrenheit (minus 180 degrees Celsius)." Google

It is a bit more stable at the poles. So, where are you going to find your iron ore? Will you process it where you find it? Despite the temperature variations. You might get very lucky and find ore close to the poles?

You have to take all your processing plant (do they still use Bessemer converters?) from Earth, and work out the power supply which is not goung to be suitably placed to connect with the Sun's energy. Then you have to transport your iron/steel to ? Earth? Moon? Mars? If not Earth, you will have similar (though milder) temperature variations.

Then you have to factor in all the living costs/expenses for man to inhabit Mercury and wherever else. Food, water, and shelter etc..

Would you please locate (hypothetically) your iron ore, and decide where to put your refining unit for the ore, especially notice the geographical difference between these. Remember, you won't get much energy at the poles - or perhaps you will choose lower latitudrs?

Believe me, I am a Chemical Engineer and have a good idea of the practicalities involved. I would welcome a friendly discussion where we can debate these issues.

Cat