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Many space advocates are strongly in favor of space solar power (SSP). These would be very large satellites, typically in GEO synchronous orbit collecting sunlight 24/7 and then beaming that energy to rectenna on Earth for transmission through existing power networks. The advantages of SSP are several-fold:

  • There is essentially no night at GEO and so this gives twice the amount of power compared to solar panels on Earth. It can thus also provide continuous, baseload power.
  • In the mornings and evening, sunlight passes through a lot of atmosphere prior to being collected on solar panels. But in free space, there is no reduction in the solar power hitting the panels.
  • Solar power satellites can, theoretically, redirect its beam to different points on the globe according to the energy needs.
  • Solar power satellites can beam power to where there is not an existing, robust electrical grids. So, for the military, very rural areas, and mining operations this can be a big plus.
  • Most importantly, solar power satellites don't produce ongoing CO2 or nuclear waste like fossile fuels and fission power respectively. So from the standpoint of the environment, its perhaps the best.
So, with all of these benefits, why don't we have SSP already?

High launch costs have been the main reason why SSP has not gotten off the ground (pun intended). The large mass needed to reach even just a gigawatt power plant would cost much more than compared to achieving the same thing using terrestrial alternatives. SSP designs have improved over the years but it is only with the nearly arrived Starship that we can plausibly begin to consider actual implementation. The fact that SSP advocates have not raised practically any money from investors and primarily look to government for demonstrations suggests that we are not at financial escape velocity yet.

Secondly, SSP is only financially competitive compared to alternatives (current and future). So for example, there are plenty of modular, thorium, etc fission power plant designs that will likely mature by the time that SSP is feasible. Will SSP be able to compete with those? One day, fusion power facilities will be a thing. Again, will SSP compete with that?

The Space Development Network believes that we should focus on the relative near term and not spend much money developing systems until they are close to being feasible. Our belief is that SSP is quite a number of years away from feasibility and may or may not be competitive when it does. However, given how near term Starship is and its anticipated capability, we believe that space dollars would be best spent establishing humanity's first permanent foothold off Earth and proceeding with actual settlement. Then, as launch prices come down and SSP technology readiness levels improve, then we can look at SSP. Until then, we believe that the great deal of focus on SSP by many in the space advocacy community is diverting attention from the more near-term objective of space development and settlement.

Space solar power may exist in the future but our near term focus should be on the development and settlement of space.

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