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A Dyson swarm is a collection of solar collector satellites around a star, capturing the majority of its light. Each solar collector is essentially a mirror. Each group of solar collector satellites - say, each 5,000 satellites - focuses sunlight on a power collector satellite, which would presumably convert the solar (light) energy to electrical energy, or some other form of beamable, usable energy.

I'm interested in how the power collector satellites would be converting the solar energy to electrical energy. There are two current technologies used for converting solar (light) energy to electrical energy:

  • Directly, via photovoltaic cells
  • Indirectly, via steam turbines and a fluid heated by solar energy (whether through a parabolic trough, heliostats, or other concentrated thermal approach)

I have doubts as to either method being a valid approach, since the concentrated solar power being received by each power collector satellite would burn a photovoltaic cell and turn most fluids into plasma.

To put it into context, Mercury (the approximate location of a dyson swarm) receives $9116.4\ \mathrm{W/m^2}$ of light energy, and assuming 5,000 satellites each of $1\mathrm{\ km^2}$ size, that would be a concentration of 45,582,000,000,000 watts (45 trillion watts) on a very small area. Given $c = \frac{E}{m \Delta T}$, and assuming that the power collector satellite would likely be made of steel, which has a specific heat capacity of 466 J/kg·K, as well as a 1000 kg collector satellite, such a concentration of energy would cause an increase in the temperature of a power collector satellite of 97,815,451°C. While such temperatures are present in inertial confinement fusion reactors (which easily achieve temperatures above even this), I find it difficult to believe that a photovoltaic cell or fluid/turbine assembly in direct contact with the sunlight would survive.

Which of the two methods (if any) would be most suitable for a power collector satellite in a Dyson swarm? And is there a more suitable method for energy collection?

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  • $\begingroup$ Questions like this are better suited to space.se. $\endgroup$
    – J.G.
    Aug 16, 2022 at 17:59
  • $\begingroup$ Your 100 MK temperature calculation, presumbaly set over a 1s period, is wrong. At high temperatures, objects have higher heat capacity and radiate much of their received heat. Obviously, sunlight can't make something hotter than the Sun's core that easily. $\endgroup$
    – J.G.
    Aug 16, 2022 at 17:59
  • $\begingroup$ @J.G. Thank you for pointing that out, and yes, I will make sure to ask future questions of this sort on space.se $\endgroup$
    – JS4137
    Aug 19, 2022 at 13:59

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A superior method of energy collection is to transmit the solar beam as one beam from the power satellites to a collection point near Earth, where another power satellite array could then split the single (incredibly high-energy) beam into numerous (likely tens of thousands of) smaller beams. Then, each satellite in the array would convert their lower-energy beams to microwaves that can be picked up by rectennas on receiver stations on Earth. Doing so avoids needing to use photovoltaics/fluid-turbine approaches entirely.

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