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So largely I believe the plan is to use microwaves to send the power back to earth so you don't have to have anything processed in space. This would usually inv

So largely I believe the plan is to use microwaves to send the power back to earth so you don't have to have anything processed in space. This would usually involve ground stations that would receive the power.

cduzz 3y ago
Right -- microwaving the ground is just moving the energy, which may or may not actually be efficient. On the face of it it seems silly, but so does making a rocket out of water towers and landing it on it's ass on the moon, so I've re-calibrated 'silly'. Nevertheless -- finding ways to move refined products around that embody a huge amount of energy is the traditional way to approach this problem. And anti-matter, if you could package it, is an obvious example....
- sbradford26 3y ago
  Yeah with space it is typically more efficient to move energy versus mass. The efficiency may not be great but you get to balance it with the increased efficiency of solar panels being located in space. So independent component efficiencies might be overshadowed by large end to end system efficiency gains.
  - bglusman 3y ago
    oh, whoops, somewhat duplicated your point, sorry!
- bglusman 3y ago
  The book Critical Mass by Daniel Suarez is my only source, but, the efficiency of rectenna is discussed there, and particularly, though the efficiency of the transmission is somewhat low, the efficiency of solar panels in space is MUCH higher than on earth, and they can operate 24/7, so the overall system efficiency is still substantially higher than the equivalent solar panels on earth... at least, assuming you can build the solar panels in space from mined material as they do in the book, I imagine if you needed to launch all the material from earth, it would probably be a fairly different story, assuming you included that in the calculations.
  - giantrobot 3y ago
    > the efficiency of solar panels in space is MUCH higher than on earth Not really. The biggest difference between a panel on Earth and one in space is the space panel is illuminated 23 hours a day. So per panel you're getting 2-3x the illumination over the course of the day. The drawback is even at the absolute cheapest pie in the sky Musk estimates of cost to orbit ($10/kg), a space solar panel is orders of magnitude more expensive than a ground panel. You could just deploy 3x the number of panels on Earth for 3x the price vs deploying in space at x\^3 the price. Even with the near constant illumination of panels in space the losses from RF conversion, free space losses, atmospheric losses, and RF rectification eliminate a lot of your power gains. For those losses you also incur significant costs. So SBS is kind of a lose-lose problem. Every technology that would make SBS more practical could be applied on the ground for a tiny fraction of the cost.
    - dabluecaboose 3y ago
      >The biggest difference between a panel on Earth and one in space is the space panel is illuminated 23 hours a day Small nitpick, but as a GEO satellite navigator I want to point out that the solar panels are in sunlight constantly except for "eclipse season" around the equinoxes. During eclipse season it can be in shadow for about an hour.
      - giantrobot 3y ago
        Thanks for the correction. So 23.76 hours a day (averaged over a year).
    - LargoLasskhyfv 3y ago
      Only if ignoring all externalities. If the panels could be manufactured in space, or on the moon, via some ultrasmall in-situ-utilizer bootstrap gizmothingy, which would then use material from the moon, or asteroids, we'd save much mining and manufacturing here on earth. Which has its own costs. As we all should know, meanwhile?
- oceanplexian 3y ago
  It’s not efficient for replacing power sources on the ground, but for airplanes, ships, and remote communities it could be genius. No need to carry heavy batteries around and your capacity is virtually unlimited (At least as far as it is feasible to build a massive orbital solar array).
  - ETH_start 3y ago
    Why isn't it efficient for replacing ground based power sources? In the case of replacing ground based solar, it means not having to deal with intermittency and diplacement of natural habitats. In the case of hydrocarbon-based power plants, it means not having to contend with pollution.

cduzz 3y ago

Right -- microwaving the ground is just moving the energy, which may or may not actually be efficient. On the face of it it seems silly, but so does making a rocket out of water towers and landing it on it's ass on the moon, so I've re-calibrated 'silly'. Nevertheless -- finding ways to move refined products around that embody a huge amount of energy is the traditional way to approach this problem. And anti-matter, if you could package it, is an obvious example....

sbradford26 3y ago
Yeah with space it is typically more efficient to move energy versus mass. The efficiency may not be great but you get to balance it with the increased efficiency of solar panels being located in space. So independent component efficiencies might be overshadowed by large end to end system efficiency gains.
- bglusman 3y ago
  oh, whoops, somewhat duplicated your point, sorry!
bglusman 3y ago
The book Critical Mass by Daniel Suarez is my only source, but, the efficiency of rectenna is discussed there, and particularly, though the efficiency of the transmission is somewhat low, the efficiency of solar panels in space is MUCH higher than on earth, and they can operate 24/7, so the overall system efficiency is still substantially higher than the equivalent solar panels on earth... at least, assuming you can build the solar panels in space from mined material as they do in the book, I imagine if you needed to launch all the material from earth, it would probably be a fairly different story, assuming you included that in the calculations.
- giantrobot 3y ago
  > the efficiency of solar panels in space is MUCH higher than on earth Not really. The biggest difference between a panel on Earth and one in space is the space panel is illuminated 23 hours a day. So per panel you're getting 2-3x the illumination over the course of the day. The drawback is even at the absolute cheapest pie in the sky Musk estimates of cost to orbit ($10/kg), a space solar panel is orders of magnitude more expensive than a ground panel. You could just deploy 3x the number of panels on Earth for 3x the price vs deploying in space at x\^3 the price. Even with the near constant illumination of panels in space the losses from RF conversion, free space losses, atmospheric losses, and RF rectification eliminate a lot of your power gains. For those losses you also incur significant costs. So SBS is kind of a lose-lose problem. Every technology that would make SBS more practical could be applied on the ground for a tiny fraction of the cost.
  - dabluecaboose 3y ago
    >The biggest difference between a panel on Earth and one in space is the space panel is illuminated 23 hours a day Small nitpick, but as a GEO satellite navigator I want to point out that the solar panels are in sunlight constantly except for "eclipse season" around the equinoxes. During eclipse season it can be in shadow for about an hour.
    - giantrobot 3y ago
      Thanks for the correction. So 23.76 hours a day (averaged over a year).
  - LargoLasskhyfv 3y ago
    Only if ignoring all externalities. If the panels could be manufactured in space, or on the moon, via some ultrasmall in-situ-utilizer bootstrap gizmothingy, which would then use material from the moon, or asteroids, we'd save much mining and manufacturing here on earth. Which has its own costs. As we all should know, meanwhile?
oceanplexian 3y ago
It’s not efficient for replacing power sources on the ground, but for airplanes, ships, and remote communities it could be genius. No need to carry heavy batteries around and your capacity is virtually unlimited (At least as far as it is feasible to build a massive orbital solar array).
- ETH_start 3y ago
  Why isn't it efficient for replacing ground based power sources? In the case of replacing ground based solar, it means not having to deal with intermittency and diplacement of natural habitats. In the case of hydrocarbon-based power plants, it means not having to contend with pollution.