7 ms·

This idea never made any sense to me. Why the heck would you spend billions of dollars to launch solar panels into space to gather sunlight then beam it to eart

This idea never made any sense to me. Why the heck would you spend billions of dollars to launch solar panels into space to gather sunlight then beam it to earth when you could just wait for the sunlight to get to earth naturally for free...

nine_k 3y ago
The fact that a powerful microwave beam shooting precisely from the orbit is also a weapon platform (if directed outside the receiver) might have played some role.
- MrOwnPut 3y ago
  A real-life Hammer of Dawn (gears of war) Really though I don't see this scaling to energy production for the masses due to the beaming logistics. It'll mainly be used to recharge drones that never land and possibly fry enemy systems / missiles / etc.
- DennisP 3y ago
  Not with a satellite in geostationary. The beam concentration on the ground would be too low to hurt anyone. You'd need a collector miles wide. With modern modular designs using phased array transmitters, even getting that much focus requires a reference signal from the ground target.
kybernetikos 3y ago
Putting the cells in orbit means that there's almost no night, and there's less loss due to the atmosphere. Of course, there are loads of problems with the idea but I can see why it's intuitively appealing.
- jackmott 3y ago
  there is loss from the atmosphere when you beam it down
  - pfdietz 3y ago
    Not much, typically.
    - MrOwnPut 3y ago
      I think 60% over a kilometer is the best efficiency thus far. What is the "typically" you are referencing?
      - pfdietz 3y ago
        Microwave beams are attenuated in heavy rain. Typically, the beam is not going through heavy rain. The 60% over a kilometer is not due to atmospheric absorption, it's due to losses at the transmitter and receiver (and beam spread exceeding the size of the receiver.) If microwaves lost 40% of their energy in a kilometer radar would have a hard time working. Millimeter waves are more strongly absorbed in clear air, so they are not as good for this use case. They may be good for powering aircraft.
  - kybernetikos 3y ago
    yes, but you can concentrate the beam more than sunlight so that there's less atmosphere involved. You can also choose a beam technology (wavelength etc) based on it going through the atmosphere well, rather than having to stick with sunlight's properties.
- Cthulhu_ 3y ago
  The loss from the atmosphere is not the issue; plenty of energy still hits the earth while the sun is out, plenty of methods of capturing it (solar panels, mirrors to focus the heat, etc), the issue is that someone actually has to build it and it goes off at night. That, and transport.
  - kybernetikos 3y ago
    Indeed, and this project is a way of fixing the "it goes off at night" problem by making all the other problems massively harder.
Faint 3y ago
Yeah, no night, no atmosphere, constant power output, lot's of real estate, and panels in space do not need heavy superstructure to withstand weather or gravity, thus they could potentially be extremely light for the area (micrometers to tens of micrometers thick at most needed for light absorption). And in far future, if they are built of materials taken from moon or meteorites, you could also bypass most of the lifting cost for even that. Of course, that would need huge scale to justify the R&D to pull it off. Anyway, space based solar power is the end game. Nothing on earth will ever provide the quantities of power (not even nuclear, fusion or fission) that capturing solar energy can.
- sandos 3y ago
  Conclusion: everyone will eventually live in orbit!
  - XorNot 3y ago
    I mean probably? We can't manufacture more real estate down here as easily as you could up there (once certain technologies are common place).
- ZeroGravitas 3y ago
  > constant power output Worth noting this isn't as much of a benefit as it's made out to be. If you were designing a perfect power source, it would match demand, so produce more in winter in polar regions, and more in summer for regions with lots of AC. Similarly, you'd generally want more power during the day than at night. This is part of the reason a mix of solar and wind that varies by latitude is an ideal mix. Space power might get more bang for buck if it could target its power to different regions e.g. swapping from north to south as the seasons change, and/or following the day/night cycle and/or weather to maximise energy price.
  - DennisP 3y ago
    The satellites would be in geostationary, with phased-array transmitters, focused by a reference signal from the ground target. They actually could be repointed to various receivers. The ground stations would be relatively cheap so it wouldn't be all that important to maximize their utilization. (Source: The Case for Space Solar Power)

nine_k 3y ago

The fact that a powerful microwave beam shooting precisely from the orbit is also a weapon platform (if directed outside the receiver) might have played some role.

MrOwnPut 3y ago
A real-life Hammer of Dawn (gears of war) Really though I don't see this scaling to energy production for the masses due to the beaming logistics. It'll mainly be used to recharge drones that never land and possibly fry enemy systems / missiles / etc.
DennisP 3y ago
Not with a satellite in geostationary. The beam concentration on the ground would be too low to hurt anyone. You'd need a collector miles wide. With modern modular designs using phased array transmitters, even getting that much focus requires a reference signal from the ground target.

kybernetikos 3y ago

Putting the cells in orbit means that there's almost no night, and there's less loss due to the atmosphere. Of course, there are loads of problems with the idea but I can see why it's intuitively appealing.

jackmott 3y ago
there is loss from the atmosphere when you beam it down
- pfdietz 3y ago
  Not much, typically.
  - MrOwnPut 3y ago
    I think 60% over a kilometer is the best efficiency thus far. What is the "typically" you are referencing?
    - pfdietz 3y ago
      Microwave beams are attenuated in heavy rain. Typically, the beam is not going through heavy rain. The 60% over a kilometer is not due to atmospheric absorption, it's due to losses at the transmitter and receiver (and beam spread exceeding the size of the receiver.) If microwaves lost 40% of their energy in a kilometer radar would have a hard time working. Millimeter waves are more strongly absorbed in clear air, so they are not as good for this use case. They may be good for powering aircraft.
- kybernetikos 3y ago
  yes, but you can concentrate the beam more than sunlight so that there's less atmosphere involved. You can also choose a beam technology (wavelength etc) based on it going through the atmosphere well, rather than having to stick with sunlight's properties.
Cthulhu_ 3y ago
The loss from the atmosphere is not the issue; plenty of energy still hits the earth while the sun is out, plenty of methods of capturing it (solar panels, mirrors to focus the heat, etc), the issue is that someone actually has to build it and it goes off at night. That, and transport.
- kybernetikos 3y ago
  Indeed, and this project is a way of fixing the "it goes off at night" problem by making all the other problems massively harder.

Faint 3y ago

Yeah, no night, no atmosphere, constant power output, lot's of real estate, and panels in space do not need heavy superstructure to withstand weather or gravity, thus they could potentially be extremely light for the area (micrometers to tens of micrometers thick at most needed for light absorption). And in far future, if they are built of materials taken from moon or meteorites, you could also bypass most of the lifting cost for even that. Of course, that would need huge scale to justify the R&D to pull it off. Anyway, space based solar power is the end game. Nothing on earth will ever provide the quantities of power (not even nuclear, fusion or fission) that capturing solar energy can.

sandos 3y ago
Conclusion: everyone will eventually live in orbit!
- XorNot 3y ago
  I mean probably? We can't manufacture more real estate down here as easily as you could up there (once certain technologies are common place).
ZeroGravitas 3y ago
> constant power output Worth noting this isn't as much of a benefit as it's made out to be. If you were designing a perfect power source, it would match demand, so produce more in winter in polar regions, and more in summer for regions with lots of AC. Similarly, you'd generally want more power during the day than at night. This is part of the reason a mix of solar and wind that varies by latitude is an ideal mix. Space power might get more bang for buck if it could target its power to different regions e.g. swapping from north to south as the seasons change, and/or following the day/night cycle and/or weather to maximise energy price.
- DennisP 3y ago
  The satellites would be in geostationary, with phased-array transmitters, focused by a reference signal from the ground target. They actually could be repointed to various receivers. The ground stations would be relatively cheap so it wouldn't be all that important to maximize their utilization. (Source: The Case for Space Solar Power)