Odd that he lists the mostly solved problems as the "huge challenges", but ignores the "make one of these things actually work" and "make it not be a bloody superweapon of hideous death"
Boffins brew up FIRST CUPPA in SPAAACE using wireless energy (well, sort of)
Japanese scientists have claimed a breakthrough in beaming energy wirelessly, after they used microwaves to deliver 1.8 kilowatts of power though the air to a receiver a short distance away. That amount of power is enough to run an electric kettle, researchers at the Japan Aerospace Exploration Agency (JAXA) enthused. "This …
COMMENTS
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Sunday 15th March 2015 20:10 GMT Yet Another Hierachial Anonynmous Coward
Olympic Sized Swimming Pool
"The microwaves reached a receiver 55 metres (or 170 feet) away – which is a little bigger than the typical length of an Olympic-sized swimming pool."
Yes, but how many kettle-fulls are in an OSSP, and how long would it take 1.8kilowatts to heat them all? The article does seem very short of useful facts and figures.....
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Sunday 15th March 2015 20:13 GMT Anonymous Coward
energy for cloud-cuckoo land
For space solar to make sense either atmospheric attenuation of solar energy would have to be enormous (so that one orbiting panel replaces one thousand on earth) or it has to be supplementary, i.e. after carpeting the Sahara with panels still more power is needed (and then the energy yield still has to exceed the input of getting them into orbit and maintaining them there. In fact attenuation isn't that bad (skim read of wikipedia suggests 50-75%) and short of a space elevator or nanomachines processing captured asteroids directly into panels I doubt they can be built in an energy-profitable way (and that's completely disregarding other costs)
So fine research, keep it up - but stop justifying it as "gonna make peace with Greenpeace"
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Monday 16th March 2015 02:10 GMT Martin Budden
Re: energy for cloud-cuckoo land
For space solar to make sense either... ...or it has to be supplementary, i.e. after carpeting the Sahara with panels still more power is needed
The reason we haven't already carpeted the Sahara with panels is transmission costs. Yes the Sahara gets lots of sunshine, yes the land in the Sahara is dirt cheap (pun intended), but the problem is the Sahara is a long way from major population & industrial centres where the electricity could be sold for $$$ (e.g. Germany). This bit of Japanese research is trying to improve transmission costs, but only works line-of-sight which means space-panels is the target application.
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Monday 16th March 2015 07:32 GMT BristolBachelor
Re: energy for cloud-cuckoo land
Why from space? Because except for a few days around the equinox, the satellite has sunlight 24/7 (and even then, the longest "night time" is about 70 mins in 24 hours). The Sahara has nights in between all the daytimes, which is not great if you want 24 hour power.
As far as the amount of power and birds, etc, the normal plan is to beam the power with a density of about 1kW/M^2, which is the same a normal sunlight. One thing missing from this report is efficiency - normally conversion to microwave is normally only about 50% efficient.
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Monday 16th March 2015 09:26 GMT Phil O'Sophical
Re: energy for cloud-cuckoo land
Normal photovoltaic cells are heading for 20% efficiency. Even if they only get full sunlight for, say, 25% of the day, this would mean that 20m² of earthbound solar panels could produce the same net energy as a 1m² microwave satellite reception antenna, and the satellite would have to have 10m² of solar panels to collect that energy (allowing for the stated 50% conversion to microwave efficiency).
I still don't see how this could be viable, when you consider the relative cost of 20m² of earthbound solar panels, versus that of lofting a satellite with 10m² of solar panels + the ground station.
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Monday 16th March 2015 21:39 GMT Martin Budden
Re: energy for cloud-cuckoo land
There are fairly large swaths of desert in North America (southwestern US) and Australia. Replicating "Sahara carpeting" in the other two regions would get much closer to 24 hour coverage, would it not?
Yes it would BUT how would you get the power from those uninhabited remote deserts to cities all around the world?
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Tuesday 17th March 2015 13:22 GMT Ugotta B. Kiddingme
Re: energy for cloud-cuckoo land
Yes it would BUT how would you get the power from those uninhabited remote deserts to cities all around the world?
Some companies already are planning to do just that. Like this. (link goes to pic of transmission lines coming from the Hualapai Valley Solar project in Arizona)
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Sunday 15th March 2015 20:31 GMT Anonymous Coward
Microwave RECEIVING satellites
Given the enormous cost of gettings stuff into space, and the flimsy nature and low power output of solar panels I think JAXA have got the idea backwards. They should use solar panels on the ground to power microwave transmissions to satellites instead. That way the energy is relatively clean, the satellites are mechanically simpler and more durable (because of less surface area to micrometeorites), and no one is at risk of being accidentally vaporised from above.
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Sunday 15th March 2015 20:52 GMT JassMan
Will nobody think of the pigeons (and microlight pilots)?
Already we have architects making curved building which cook the paint off cars, sculptors making parabolic mirrors as "art" which almost vaporises pigeons before they fall out of the beam and now they want to use a microwave not contained inside a faraday cage. No matter how accurate they can beam to a given point on earth there will always things which can't read the signs before they fly through the restricted airspace above the receivers.
Since someone has already mentioned a space elevator, why not build 2, then they can use them as both conductors of a power cable. Send it as HVDC and you could achieve much lower losses than any micro wave.
Is it too late to patent a system of parachutes attached to the elevator cables such that in the event of the satellite becoming detached, the chutes act just like the drogue on a glider tow line.
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Sunday 15th March 2015 22:24 GMT x 7
I always thought the plan was always to beam microwaves down from the satellite through a superheated plasma beam so there'd be no risk of atmospherics interfering with the microwaves. The plasma acts as a kind of waveguide.
Of course you'd need a decent power supply to create and maintain the plasma.
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Monday 16th March 2015 07:28 GMT Faux Science Slayer
Photovoltaics is a crude, molecular erosion parlor trick....
Solar cells are a one time, one way molecular erosion process that NEVER 'produces' the energy required to 'create' solar cells. Microwaves are deadly at higher power levels. The sky based PV panel, transmitting power back to Earth is science fiction that is absurd.
See "Green Prince of Darkness" at the FauxScienceSlayer site
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Tuesday 17th March 2015 09:17 GMT Conundrum1885
Re. power
Using metamaterials could also work, the beam could be quite large then a stratellite array at 45K feet would upconvert the (diffuse) microwave beam into the required narrow IR non coherent beam for use with existing solar power stations optimized for infrared light.
This would be an excellent use for ionocraft technology combined with longlife envelopes and onboard H2 production to keep the stratellites aloft and on target.
If something goes wrong the second the beam misaligns power is lost and the system self corrects.