Electricity infrastructure in space?

A discussion with Andy Hill that mentioned electricity creation in space and beaming it down to Earth by microwaves or laser stimulated some ideas about electricity infrastructure - and I think I should start a new thread about it.

What are the maximum distances microwaves or laser are working efficiently in bemaing electricity to? At what distances relay stations would be required?

If it is possible to generate electricty in space and beam it down to the earthian surface it is possible too to beam electricity to satellites and vehicles moving in space. If that would be done the energy provided by nuclear power sources could be saved for times when no electricity beam is available.

Are microwaves and lasers efficient enough to beam electricity to the distance of Mars or would relay stations be required? and how much if yes?

ESA mentioned the requirement od nuclear power sources at missions to Titan etc. and NASA is used to use these power sources. But one day these power sources too are exhausted. Could the radiation belts of Jupiter, Saturn, Uranus or Neptune be used to generate electricity and bema it to probes orbiting these planets or going down to the surface of their moons? To what amount can the capacity of accumulators be extendedß The beams could load accumulators that have sufficinet capacity to provide electricity to probes and rovers for the whole time when the beams cannot reach the probes and rovers.

Is something of this possible based on microwaves or lasers?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

My rough calculations say that a 200 meter diameter reflector could send a visible light laser beam to Mars (at closest approach) tight enough to be captured by a receiver of the same diameter. Of course the aim would have to be within a few meters or the receiver would have to be larger by an amount equal to the aiming error to capture all of the beam. When Mars is at it's farthest distance from Earth, say 7 times as far, the diameters would have to be 7 times as large. For microwave energy the antennas would have to be much larger. It scales directly with wavelength, so microwaves with a wavelength 1000 times longer than light would require antennas 1000 times larger.

So I think it could be done with laser light, but not microwaves, and no relays at all. Especially with Mars near opposition.

This makes it pretty doable for a lunar power beam using a laser. Something like a 5m reflector would mean you could have a small tolerance on accuracy. You would probably need a few satellites placed in orbit around the Earth so that you could relay the beam to a specific location on the surface.

It could work both ways and you could supply the moon from Earth initially to power equipment building the lunar base.

You would have the Earth's atmosphere messing up any outgoing beam. When astronomers bounce laser light off the moon the spot ends up several kilometers across on the moon I think.

Also, I was wondering, what would the power output of a 200 meter wide solar cell array at Mars be? It might not be worth beaming the laser there after all. Just use local solar power. I guess it would depend on how powerful the laser was.

I was wondering the same thing (Why beam energy when the sun is already beaming a whole lot that may be captured with a solar array).

I guess it depends largely on the energy requirements at the specified base, or if the base were to be in an eclipsed portion of the moon. Even with one of these cases, though, would it not make more sense to beam the energy from a satellite (obtaining its energy from either the sun or a contained nuclear reactor (far distant in realizable time, I'd imagine)? This way one would not need to be bothered by much atmospheric scattering of the beam.

My main concern with this, though, would be other potential uses for such a high-energy beam from space. Where would the money for this type of a project come from? It may be a bit of a silly stretch, but if any of you remember the movie "Real Genius" with Val Kilmer, it seems as though the military would be quick to recognise the strategic benefit of such a project. I, for one, wish to limit and postpone as much as possible the militarization of space, and do not look forward to another arms race.

The money could come from all those electricity industries that are forbidden to use nuclear or fossile energy powers - perhaps.

Additionally I asked for providing electricity (got in space) to satellites and space vehicles by microwave or laser.

What about the extensions to make use of all this to provide power for vehicles at Jupiter or Saturn etc. too?

Concerning Earth, moon and - especially - Mars: What about relay stations in several orbits between Earth and monn or between Earth and Mars? Could they reduce the required diamter of the antennas? And is there a technology that is working efficiently enough to store energy received until beaming it further to its destination?



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Yeah, why doesn't Iran forget about nuclear power and build Giant microwave beams on orbit.

An excellent way to supply commercial power...

No relay stations should be needed for so short a distance as Earth to Moon. After all, even when Mars is at it’s closest approach to Earth, the Moon is still 140 times closer.
Relays between Earth and Mars would not work because Earth and Mars orbit the Sun at different speeds. Sometimes they pass close to each other and sometimes they are on opposite sides of the Sun. The same would be true for relay stations between Earth and Mars. They would orbit the Sun slower than Earth but faster than Mars. You would need hundreds of relays spread out between Earth and Mars. At any one time, only the ones on a direct line between Earth and Mars would be used, while all the others waited, unused, for their turn to be in line. It would be like burning some kind of expensive hardwood instead of coal to fire a boiler. You COULD do that, but it would totally impractical and economically wasteful. Local solar or nuclear power makes much more sense over interplanetary distances.

I'm very familiare with the different velocities Mars and Earth are orbiting by - that's the reason wha I asked for the efficient technology to store energy received by a beam until it can be sent further by beam to its ultimate destination.

My idea is to beam the electricity to a relay station when it's close to Earth and to store it there. After Earth has passed the relay station the station will wait until it's close to Mars and send the stored electricity further to Mars. There could be several relay stations between Earth and Mars this way.

As far as I know accumulator technology still has to be improved. But there seem to be alternative technologies.

Another idea perhaps could be to generate the electricity by equipment orbiting sun at a closer distance. Can it be beamed to a larger distance then? At least relay stations that can store the electricity could be used in that case too.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

We do not even have the technology to store large amounts of energy overnight well enough to make ground based solar power useful. So, no, we can’t store it for months in space either.

This is not a talk about beaming electricity to Mars in 2005 - it's a talk about an idea that might become reality years or decades in the future. Until that time the technologies to store electricity can be improved - as far as I know there is work on improvements. So that's no k.o.-argument.

As the years are passing by first the technology to beam electricity down to Earth would be developed.

Next that technology would be improved and used to beam energy to the moon.

After that time will pass and then a relay station would or could be constructed, built and installed. This too would require several years. Within the period between now - 2005 - and that step of development of a relay station where the storage technology has to be available there is much time to research for ways of improvement of the storage technology. It's not guaranteed, that the required improvement will be achieved but it has to be tried - and the scientists and engineers ARE working on it.

Perhaps incentives should be set - perhaps they should be set by a private organization...



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

In my opinion, it won't work. You don't have to accept it. It is just my opinion.

The inefficiencies and complexity of beaming power over long distnaces just make it too difficult. (in my opinion of course). Better to utilise local conditions for power, or a nuke.

Perhaps developments and researches for a space elevator will result in improvements of efficiency and reductions of complexity of power beaming.

Edwards provided in his study power beaming by laser from ground.

The elevator:2010 competition contains one prize for a solution to provide electricity for the climber of the elevator.

This may open new way for beaming power over long distances too or at least make easier existing ways. It may be interesting to watch that competiton for these reasons.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

Erm, aren't carbon nanotubes conductive? I think they are. If so, then power may be sent up the thread of a space elevator? Each climber could pick up the power from inductive pickups? Would we require loops to be woven in the ribbon?