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Large space-based solar installations are feasible, the only big problem is transmission of the power, usually proposed via laser or directed energy beam to the

Large space-based solar installations are feasible, the only big problem is transmission of the power, usually proposed via laser or directed energy beam to the ground. That is technically feasible, but nobody has ever attempted to wirelessly transmit such high levels of sustained energy over long distances. Depending on the transmitter and receiver efficiencies and what wavelengths are used a lot of power could be lost and there are potential disasters like missing your target receiver with your energy beam, or interactions of the air with such a high powered beam, or EM 'pollution' from an imperfect transmitter. As for something like tethering orbiting objects or the like, it is all still theoretical. A space elevator requires similar material technologies and nobody has found a way to feasibly build such a large, strong, and light tether or chain. But that isn't something I would expect to see any time soon.

didericis 7y ago
I was thinking of a smaller electrodynamic tether that would be floating in space rather than anything anchored or as long as a space elevator. I’d assume the stresses would be significantly less/more feasible to overcome, but that’s a naive assumption. Maybe a power generating, floating electrodynamic tether would have to be similarly super long and strong to generate meaningful amounts of electricity; I know fairly little about them, but they sounded more plausible than a space elevator to me.
- AngryData 7y ago
  I guess I just don't understand where the generation capacity comes from that because it is trading kinetic energy into electrical but that kinetic energy has to come from somewhere or you will deorbit your anchor. Although now that I think about it, you could potentially nudge a conveniently positioned space rock into a sacrificial eccentric orbit around earth and harvest energy off that ever time in skims by until it finally crashes down into the earth.
  - didericis 7y ago
    I don't understand it either. Am assuming we're both looking at the wikipedia article, unless you have another source/are going from something else: https://en.wikipedia.org/wiki/Electrodynamic_tether#Tethers_as_generators https://en.wikipedia.org/wiki/Electrodynamic_tether#Tethers_... > When the tether intersects the planet's magnetic field, it generates a current, and thereby converts some of the orbiting body's kinetic energy to electrical energy. Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. As a result of this process, an electrodynamic force acts on the tether and attached object, slowing their orbital motion. In a loose sense, the process can be likened to a conventional windmill- the drag force of a resistive medium (air or, in this case, the magnetosphere) is used to convert the kinetic energy of relative motion (wind, or the satellite's momentum) into electricity. In principle, compact high-current tether power generators are possible and, with basic hardware, tens, hundreds, and thousands of kilowatts appears to be attainable. Maybe cosmic radiation interacting with the magnetosphere is adding to the "wind" in the analogy; not sure. Agree that the explanation makes it sound like you'd basically just be turning launch energy into electricity, which doesn't sound useful for generating power to send back to earth. Nudging space rocks into orbit to generate electricity is a cool sounding idea. I've heard similar proposals for space mining if and when it becomes a thing just to make transporting the material a lot easier. Not sure how plausible that is either. Regardless of what form it takes, I really hope we get some serious and practical space infrastructure at some point. I think having a practical reason to go into space beyond just gathering astronomical data and doing experiments will help keep space programs from stagnating. Plus it'd be super cool.

didericis 7y ago

I was thinking of a smaller electrodynamic tether that would be floating in space rather than anything anchored or as long as a space elevator. I’d assume the stresses would be significantly less/more feasible to overcome, but that’s a naive assumption. Maybe a power generating, floating electrodynamic tether would have to be similarly super long and strong to generate meaningful amounts of electricity; I know fairly little about them, but they sounded more plausible than a space elevator to me.

AngryData 7y ago
I guess I just don't understand where the generation capacity comes from that because it is trading kinetic energy into electrical but that kinetic energy has to come from somewhere or you will deorbit your anchor. Although now that I think about it, you could potentially nudge a conveniently positioned space rock into a sacrificial eccentric orbit around earth and harvest energy off that ever time in skims by until it finally crashes down into the earth.
- didericis 7y ago
  I don't understand it either. Am assuming we're both looking at the wikipedia article, unless you have another source/are going from something else: https://en.wikipedia.org/wiki/Electrodynamic_tether#Tethers_as_generators https://en.wikipedia.org/wiki/Electrodynamic_tether#Tethers_... > When the tether intersects the planet's magnetic field, it generates a current, and thereby converts some of the orbiting body's kinetic energy to electrical energy. Functionally, electrons flow from the space plasma into the conductive tether, are passed through a resistive load in a control unit and are emitted into the space plasma by an electron emitter as free electrons. As a result of this process, an electrodynamic force acts on the tether and attached object, slowing their orbital motion. In a loose sense, the process can be likened to a conventional windmill- the drag force of a resistive medium (air or, in this case, the magnetosphere) is used to convert the kinetic energy of relative motion (wind, or the satellite's momentum) into electricity. In principle, compact high-current tether power generators are possible and, with basic hardware, tens, hundreds, and thousands of kilowatts appears to be attainable. Maybe cosmic radiation interacting with the magnetosphere is adding to the "wind" in the analogy; not sure. Agree that the explanation makes it sound like you'd basically just be turning launch energy into electricity, which doesn't sound useful for generating power to send back to earth. Nudging space rocks into orbit to generate electricity is a cool sounding idea. I've heard similar proposals for space mining if and when it becomes a thing just to make transporting the material a lot easier. Not sure how plausible that is either. Regardless of what form it takes, I really hope we get some serious and practical space infrastructure at some point. I think having a practical reason to go into space beyond just gathering astronomical data and doing experiments will help keep space programs from stagnating. Plus it'd be super cool.