6 ms·

Beaming solar energy from space

67 points by danboarder 4y ago

avmich 4y ago
https://caseyhandmer.wordpress.com/2019/09/20/no-really-space-based-solar-power-is-not-a-useful-idea-literature-review-edition/ https://caseyhandmer.wordpress.com/2019/09/20/no-really-spac... (from linked previous post) "My view is that space-based solar power is impossibly expensive and will never be used on Earth."
- superkuh 4y ago
  I agree. In radio the size of the aperture across which the currents flow is inversely proportional to the size of the antenna main beam. The pattern is literally the fourier transform of the currents. The bigger the smaller. There's no getting around needing to have a giant antenna surface (or array). In order to have the required extremely tiny main beams (high gain), to not instantly lose most of the power to spreading losses, LEO beamed power at reasonable microwave frequencies requires ~5km wide aperture. We cannot build 5 km things in space yet. It is not really something worth discussing till we're doing that regularly. Space based power isn't that much more available than ground based so there's not much value added to the huge increase in cost orbit requires.
  - avmich 4y ago
    Henry Spencer (https://en.wikipedia.org/wiki/Henry_Spencer https://en.wikipedia.org/wiki/Henry_Spencer) a couple of months ago run a presentation of current state in space power. Land antennas (rectennas) were in this size, ~5km diameter, made mostly from chicken wire. Cheap, and you can still grow vegetables or anything under it. Not much risk walking under it either. Space antennas are an order of magnitude smaller, ~250 meters (for gigawatt-class power stations). To me, this all seem to need a lot of data and some careful calculations :) .
  - fnordpiglet 4y ago
    They discuss they would build a 3.5 mile array using unfolding tiles. They seem to appreciate the challenges and are researching how to overcome them. Isn’t this how we turn “cannot” into can ?
- ZeroGravitas 4y ago
  > at the end of the day, power is cheap and rapidly getting cheaper on Earth, while it remains expensive in space. Only a couple of years max before this becomes obvious to everyone so if you have any mad schemes that rely on high energy prices then your window of opportunity to land some funding is closing.
- tectonic 4y ago
  I disagree. The currently envisioned approaches are impractical due to in-orbit assembly needs, but there are other options.
  - henearkr 4y ago
    Lunar solar, with panel foundries on the Moon, resulting energy beamed to Earth.
- Pokepokalypse 4y ago
  yes. Dr. Gerard O'Neil figured this out in like 1978. Then, OPEC decided to demonstrate just how temporarily infeasible they could make it, by manipulating global oil prices (far from the first time).
rgmerk 4y ago
The only place this might make sense is at high latitudes where solar power is essentially unavailable for months on end when demand is highest. In temperate and tropical latitudes it’s unlikely to be economically competitive with solar panels on the ground.
- danboarder 4y ago
  24-hour or near 24-hour power delivery would be a big advantage to these space-based solar systems, compared to only mid-day daylight for terrestrial solar.
  - rgmerk 4y ago
    Not as much as you'd think. A modest amount of storage (for which there are a variety of options including conventional batteries, flow batteries, and pumped storage), as well as demand management (run your heat pump hot water and charge your EV in the middle of the day) is more than enough to deal with the intra-day mismatch between supply and demand. That storage isn't cheap but is likely much cheaper than launching the equivalent amount of solar array into space, where the constant supply of power still means you need to either overbuild the array or build storage to supply peaks in demand. The other thing to keep in mind is that few grids will be purely solar-powered; most large electricity grids will have wind in the mix as well. Where the equation starts to look a little more appealing is in, say, Canada and northern Europe, where your energy demand is strongly seasonal, and solar output is strongly seasonal precisely the wrong way to meet that demand (unlike, say, Australia, where peak demand correlates reasonably well with solar energy availability).
lawrenceyan 4y ago
Modular, decentralized, adaptable, no single points of failure, resilient to degradation, and cost-effective all while providing superior performance? This is amazing! Are there any downsides? I can’t think of any off the top of my head.
flarg 4y ago
What a way to de-democratize solar power!
borbulon 4y ago
> Beaming solar energy from space You mean the sun?
raasdnil 4y ago
My first thought on this is why not just build the solar panel on the ground, there must be some major efficiency gain from building this to offset the complexity and cost, or is the main benefit being able to point concentrated power to a different location? (such as a 1m square receiving panel on a moving ship?)
- Mizza 4y ago
  No atmosphere, no land to purchase, and most importantly, no night. I don't think it will be cost-competitive against alternatives, but it's sci-fi so I like it on that front.
  - raasdnil 4y ago
    Yes indeed love the sci-fi aspect :) But these things have to be commercial to work eventually... I wonder what they are seeing as the major competitive advantage. Land, perhaps yeah, but most of the land for solar type systems tends to be out where land is cheapish, but getting that electricity via a cable from a far off location would be something saved.
    - AlbertCory 4y ago
      > most of the land for solar type systems tends to be out where land is cheapish .. but not the court costs for defending against the environmental lawsuits. There are no endangered species living in outer space (that we know of, anyway). But I'm not sticking up for this idea. Which one will happen at large scale first? 1) Geothermal 2) Fusion 3) New generation fission 4) Pumped storage hydro 5) Space solar, i.e. this article 6) Other
olivermarks 4y ago
Interesting but the usual 'moving closer to reality'
r24y 4y ago
I remember this fondly from SimCity 2000, where you could build a "microwave power plant" that would collect beamed energy from space-based solar panels. (If I remember correctly, sometimes the beam would get out of alignment and set fire to nearby neighborhoods.)
- idontwantthis 4y ago
  With the event being so rare I thought it was a joke...until it happened.
Valgrim 4y ago
So far every comment on this thread miss the main customer for this tech: the military. Driving fuel trucks along thousand of kilometers where the enemy can bomb your convoy anywhere, just to run the lights and computers, is incredibly dangerous, costly and inefficient (see the wagon equation). Plus, any kind of power source you bring to the battlefield can be captured by your enemy and used against you. Who cares if beaming it from space is a thousand times more costly than what your local utility company charges you. If it can bring an advantage on the battlefield, army people will research, develop and use it.
- anonporridge 4y ago
  And beyond electricity generation, if you can beam enough solar energy down from space to power the military machine in a remote location, it's not a terribly big step to build a fucking space laser to incinerate any point of the planet at will.
  - dirtball_ 4y ago
    I'm excited for the orbital gravity mirror
  - xnx 4y ago
    The Crossbow Project: https://www.youtube.com/watch?v=DTx_qTwQqjU https://www.youtube.com/watch?v=DTx_qTwQqjU
- Retric 4y ago
  Solar + batteries + sabotage charges is a fuck of a lot cheaper for the military. Alternatively generators use vastly less fuel than tanks or aircraft etc so logistically it’s not a major issue. What they might be interested in is drones and missiles. In theory you can make a very lightweight and powerful jet engine using beamed power which then gets unlimited range. Being able to launch cheap Mach 4+ missiles from a gunboat to hit some target 5,000+ miles away is on somebody’s wishlist.
- mirekrusin 4y ago
  It would also act as high precision targeting system for enemy?
dang 4y ago
Related: Solar farms in space might beam electricity to Earth - https://news.ycombinator.com/item?id=33426956 https://news.ycombinator.com/item?id=33426956 - Nov 2022 (7 comments) Space-based solar power is getting serious - https://news.ycombinator.com/item?id=33273144 https://news.ycombinator.com/item?id=33273144 - Oct 2022 (208 comments) Europe Is Getting Serious About Making Space-Based Solar Power a Reality - https://news.ycombinator.com/item?id=32644013 https://news.ycombinator.com/item?id=32644013 - Aug 2022 (50 comments) Solaris: ESA Says Space-Based Solar Power Is a Real Option - https://news.ycombinator.com/item?id=32513122 https://news.ycombinator.com/item?id=32513122 - Aug 2022 (5 comments) On beaming solar power from low earth orbit - https://news.ycombinator.com/item?id=28426262 https://news.ycombinator.com/item?id=28426262 - Sept 2021 (86 comments) California utility bets on space-based solar power - https://news.ycombinator.com/item?id=28225254 https://news.ycombinator.com/item?id=28225254 - Aug 2021 (3 comments) $100M donation powers decade-long moonshot to generate solar-power from space - https://news.ycombinator.com/item?id=28106957 https://news.ycombinator.com/item?id=28106957 - Aug 2021 (3 comments) Beaming Down Space Solar – Air Force Research - https://news.ycombinator.com/item?id=27334259 https://news.ycombinator.com/item?id=27334259 - May 2021 (3 comments) UK government considers space-based solar power for 24/7 Solar Generation - https://news.ycombinator.com/item?id=26674956 https://news.ycombinator.com/item?id=26674956 - April 2021 (28 comments) A solar panel in space is collecting energy that could be beamed to anywhere - https://news.ycombinator.com/item?id=26262524 https://news.ycombinator.com/item?id=26262524 - Feb 2021 (5 comments) China wants to put a solar farm in space by 2025 - https://news.ycombinator.com/item?id=19190620 https://news.ycombinator.com/item?id=19190620 - Feb 2019 (59 comments) Scientists are working on space-based solar panels - https://news.ycombinator.com/item?id=10310307 https://news.ycombinator.com/item?id=10310307 - Oct 2015 (11 comments) Harvesting solar power in space and sending it back to Earth - https://news.ycombinator.com/item?id=6294565 https://news.ycombinator.com/item?id=6294565 - Aug 2013 (80 comments) Space Solar Power System - https://news.ycombinator.com/item?id=2197108 https://news.ycombinator.com/item?id=2197108 - Feb 2011 (11 comments) Will the stars align for space-based solar power? - https://news.ycombinator.com/item?id=698859 https://news.ycombinator.com/item?id=698859 - July 2009 (6 comments) New Company Looks to Produce Space Based Solar Power Within a Decade - https://news.ycombinator.com/item?id=487316 https://news.ycombinator.com/item?id=487316 - Feb 2009 (6 comments) ... and what the hell: A Material That Throws Heat into Space Could Soon Reinvent Air-Conditioning - https://news.ycombinator.com/item?id=15249089 https://news.ycombinator.com/item?id=15249089 - Sept 2017 (25 comments) Efficient Air-Conditioning Beams Heat into Space - https://news.ycombinator.com/item?id=15176721 https://news.ycombinator.com/item?id=15176721 - Sept 2017 (187 comments) Material Cools Buildings by Sending Heat into Space - https://news.ycombinator.com/item?id=8684647 https://news.ycombinator.com/item?id=8684647 - Dec 2014 (18 comments) Cooling panel sends excess heat back into outer space - https://news.ycombinator.com/item?id=5556564 https://news.ycombinator.com/item?id=5556564 - April 2013 (14 comments)
fourseventy 4y ago
I never understood the point of this. Energy is already beaming to earth from space. Much easier to just let it get to us on earth and collect it there.
- deleted 4y ago
  [deleted]
- henearkr 4y ago
  Less space constraints in orbit, also this is technology required for the next step, a Dyson Sphere, which allows to gather much much more energy.
didgetmaster 4y ago
Assuming that this technology can advance enough to become practical; are there orbits a satellite can take where it could collect sunlight continuously (i.e. it is not in the Earth's shadow very much) yet still be over a spot where it could deliver energy to a desired point on the Earth for a significant amount of time?
- 0x0203 4y ago
  You can look up sun-synchronous orbits; orbits that are mostly polar, but can be set up to continuously face the sun and without ever going into the earth's shadow. For continuous power delivery to a single ground station from such an orbit, you'd need several satellites. (If you remove the requirement to never be in shadow, but just mostly never, there are quite a few orbits that could be set up.) Geo-synchronous orbits would always be stationary above a single point on the earth's surface and could therefore potentially get away with just one solar collector, but you are guaranteed to be in shadow at some point and taking up that much space in the very precious geo-orbit is unlikely.
kaiju0 4y ago
This has been researched and found impractical. First you have power conversions solar > electric > microwave > electric. Then the microwave transmission receiver has to grow at the square of the distance. Receivers need to be huge on the order of kilometers. Also to be stationary to the ground the satellites need to be in geo orbit making the distance huge. What am I missing?
- drewbeck 4y ago
  The vision and dedication of a team of Caltech scientists
- choonway 4y ago
  competition from china. don’t want to fall behind like with the hypersonics and rail guns
plasmatorch 4y ago
I worked on this project a few years back, on the power transmission bits. It's pretty cool from the engineering side; the mechanics need to be very light, and unfold into a large area. The beaming part is just a large phased array. The hardest bit is likely high efficiency, cost effective PV cells that can survive in space, but this is a field that Atwater has been in a long time, and is very, very good at.
- kumarvvr 4y ago
  Any info on system capacity and efficiency?
  - plasmatorch 4y ago
    IIRC, it took about 50~100 W from a power supply to beam ~2.5W to a target antenna array, but that was fairly early on, so it's likely better now.
- pencilguin 4y ago
  Probably a laser would be a much better power transmission method: shorter wavelengths spread out less. You would pick a wavelength that PV panels on the ground convert most efficiently, and pump the laser cavity with focused sunlight, directly. No fooling with PV panels, then. Monochromatic light can be converted via PV with little loss. Mirrors to focus sunlight weigh practically nothing. Made of alternating layers of different index of refraction, of thickness according to the pumping wavelength, they reflect only that wavelength, and let the rest pass through. So, the laser cavity doesn't get hot, an important detail in space where cooling is hard. You would arrange so the laser light intensity is no more than of sunlight, for safety. Of course it wouldn't do much good in the daytime, but would work at night and in winter. Just, not so good through clouds.
  - pipodeclown 4y ago
    Isnt this really a question the reflectivity and amount of absorption in the atmosphere of the wavelength you're using?
AtlasBarfed 4y ago
Amazing Bond plot: Someone gets ownership of Antarctica, uses Solar panels to raise the temperature of Antarctica and melt all the snow cover, gains control of an entire new continent. Also Gundam 0083 had the solar system II superweapon, which was just mirrors. But fundamentally, isn't this increased insolation and on a large scale would accelerate warming? Man, couldn't we use a bunch of mirrors to locally warm northern climates in Siberia, Antarctica, etc... I wonder if that would be worth it.
sakitgigi 4y ago
if you can get 100wph from 1m2 of solar panel on earth, how much electricity can you get from space for an equivalent 1m2 space panel ? i read the no night argument, so if earth panel gets usable 8hr per day, the space panel automatically gets 3x gains, no ?
- drewbeck 4y ago
  The article says 8x all in
wrycoder 4y ago
This same tech was on the cover of a 1971 IEEE Spectrum magazine. I don’t see any advancement since then.
- LargoLasskhyfv 4y ago
  Roland Emmerich's first from 1984! https://en.wikipedia.org/wiki/The_Noah%27s_Ark_Principle https://en.wikipedia.org/wiki/The_Noah%27s_Ark_Principle
- MichaelZuo 4y ago
  100 km of atmosphere in the way of any 'beaming' makes the economics unviable even with recent drops in launch prices. It will likely have to be assembled in space from materials mined in space to ever work out.
  - avmich 4y ago
    Microwaves pass through atmosphere with negligible losses.
    - MichaelZuo 4y ago
      The losses certainly are not negligible, they're >> 10%.
      - fnordpiglet 4y ago
        That’s why Bruce banner was experimenting with gamma rays. It’s a shame what happened to him.
      - e12e 4y ago
        Infrared laser in wavelengths between 8 and 13 micrometers? The inverse of radiative cooling? https://news.ycombinator.com/item?id=15176721 https://news.ycombinator.com/item?id=15176721
  - guyzero 4y ago

67 points by danboarder 4y ago

https://caseyhandmer.wordpress.com/2019/09/20/no-really-space-based-solar-power-is-not-a-useful-idea-literature-review-edition/ https://caseyhandmer.wordpress.com/2019/09/20/no-really-spac... (from linked previous post) "My view is that space-based solar power is impossibly expensive and will never be used on Earth."

superkuh 4y ago
I agree. In radio the size of the aperture across which the currents flow is inversely proportional to the size of the antenna main beam. The pattern is literally the fourier transform of the currents. The bigger the smaller. There's no getting around needing to have a giant antenna surface (or array). In order to have the required extremely tiny main beams (high gain), to not instantly lose most of the power to spreading losses, LEO beamed power at reasonable microwave frequencies requires ~5km wide aperture. We cannot build 5 km things in space yet. It is not really something worth discussing till we're doing that regularly. Space based power isn't that much more available than ground based so there's not much value added to the huge increase in cost orbit requires.
- avmich 4y ago
  Henry Spencer (https://en.wikipedia.org/wiki/Henry_Spencer https://en.wikipedia.org/wiki/Henry_Spencer) a couple of months ago run a presentation of current state in space power. Land antennas (rectennas) were in this size, ~5km diameter, made mostly from chicken wire. Cheap, and you can still grow vegetables or anything under it. Not much risk walking under it either. Space antennas are an order of magnitude smaller, ~250 meters (for gigawatt-class power stations). To me, this all seem to need a lot of data and some careful calculations :) .
- fnordpiglet 4y ago
  They discuss they would build a 3.5 mile array using unfolding tiles. They seem to appreciate the challenges and are researching how to overcome them. Isn’t this how we turn “cannot” into can ?
ZeroGravitas 4y ago
> at the end of the day, power is cheap and rapidly getting cheaper on Earth, while it remains expensive in space. Only a couple of years max before this becomes obvious to everyone so if you have any mad schemes that rely on high energy prices then your window of opportunity to land some funding is closing.
tectonic 4y ago
I disagree. The currently envisioned approaches are impractical due to in-orbit assembly needs, but there are other options.
- henearkr 4y ago
  Lunar solar, with panel foundries on the Moon, resulting energy beamed to Earth.
Pokepokalypse 4y ago
yes. Dr. Gerard O'Neil figured this out in like 1978. Then, OPEC decided to demonstrate just how temporarily infeasible they could make it, by manipulating global oil prices (far from the first time).

rgmerk 4y ago

The only place this might make sense is at high latitudes where solar power is essentially unavailable for months on end when demand is highest. In temperate and tropical latitudes it’s unlikely to be economically competitive with solar panels on the ground.

danboarder 4y ago
24-hour or near 24-hour power delivery would be a big advantage to these space-based solar systems, compared to only mid-day daylight for terrestrial solar.
- rgmerk 4y ago
  Not as much as you'd think. A modest amount of storage (for which there are a variety of options including conventional batteries, flow batteries, and pumped storage), as well as demand management (run your heat pump hot water and charge your EV in the middle of the day) is more than enough to deal with the intra-day mismatch between supply and demand. That storage isn't cheap but is likely much cheaper than launching the equivalent amount of solar array into space, where the constant supply of power still means you need to either overbuild the array or build storage to supply peaks in demand. The other thing to keep in mind is that few grids will be purely solar-powered; most large electricity grids will have wind in the mix as well. Where the equation starts to look a little more appealing is in, say, Canada and northern Europe, where your energy demand is strongly seasonal, and solar output is strongly seasonal precisely the wrong way to meet that demand (unlike, say, Australia, where peak demand correlates reasonably well with solar energy availability).

lawrenceyan 4y ago

Modular, decentralized, adaptable, no single points of failure, resilient to degradation, and cost-effective all while providing superior performance? This is amazing! Are there any downsides? I can’t think of any off the top of my head.

flarg 4y ago

What a way to de-democratize solar power!

borbulon 4y ago

> Beaming solar energy from space You mean the sun?

raasdnil 4y ago

My first thought on this is why not just build the solar panel on the ground, there must be some major efficiency gain from building this to offset the complexity and cost, or is the main benefit being able to point concentrated power to a different location? (such as a 1m square receiving panel on a moving ship?)

Mizza 4y ago
No atmosphere, no land to purchase, and most importantly, no night. I don't think it will be cost-competitive against alternatives, but it's sci-fi so I like it on that front.
- raasdnil 4y ago
  Yes indeed love the sci-fi aspect :) But these things have to be commercial to work eventually... I wonder what they are seeing as the major competitive advantage. Land, perhaps yeah, but most of the land for solar type systems tends to be out where land is cheapish, but getting that electricity via a cable from a far off location would be something saved.
  - AlbertCory 4y ago
    > most of the land for solar type systems tends to be out where land is cheapish .. but not the court costs for defending against the environmental lawsuits. There are no endangered species living in outer space (that we know of, anyway). But I'm not sticking up for this idea. Which one will happen at large scale first? 1) Geothermal 2) Fusion 3) New generation fission 4) Pumped storage hydro 5) Space solar, i.e. this article 6) Other

olivermarks 4y ago

Interesting but the usual 'moving closer to reality'

r24y 4y ago

I remember this fondly from SimCity 2000, where you could build a "microwave power plant" that would collect beamed energy from space-based solar panels. (If I remember correctly, sometimes the beam would get out of alignment and set fire to nearby neighborhoods.)

idontwantthis 4y ago
With the event being so rare I thought it was a joke...until it happened.

Valgrim 4y ago

So far every comment on this thread miss the main customer for this tech: the military. Driving fuel trucks along thousand of kilometers where the enemy can bomb your convoy anywhere, just to run the lights and computers, is incredibly dangerous, costly and inefficient (see the wagon equation). Plus, any kind of power source you bring to the battlefield can be captured by your enemy and used against you. Who cares if beaming it from space is a thousand times more costly than what your local utility company charges you. If it can bring an advantage on the battlefield, army people will research, develop and use it.

anonporridge 4y ago
And beyond electricity generation, if you can beam enough solar energy down from space to power the military machine in a remote location, it's not a terribly big step to build a fucking space laser to incinerate any point of the planet at will.
- dirtball_ 4y ago
  I'm excited for the orbital gravity mirror
- xnx 4y ago
  The Crossbow Project: https://www.youtube.com/watch?v=DTx_qTwQqjU https://www.youtube.com/watch?v=DTx_qTwQqjU
Retric 4y ago
Solar + batteries + sabotage charges is a fuck of a lot cheaper for the military. Alternatively generators use vastly less fuel than tanks or aircraft etc so logistically it’s not a major issue. What they might be interested in is drones and missiles. In theory you can make a very lightweight and powerful jet engine using beamed power which then gets unlimited range. Being able to launch cheap Mach 4+ missiles from a gunboat to hit some target 5,000+ miles away is on somebody’s wishlist.
mirekrusin 4y ago
It would also act as high precision targeting system for enemy?

dang 4y ago

Related: Solar farms in space might beam electricity to Earth - https://news.ycombinator.com/item?id=33426956 https://news.ycombinator.com/item?id=33426956 - Nov 2022 (7 comments) Space-based solar power is getting serious - https://news.ycombinator.com/item?id=33273144 https://news.ycombinator.com/item?id=33273144 - Oct 2022 (208 comments) Europe Is Getting Serious About Making Space-Based Solar Power a Reality - https://news.ycombinator.com/item?id=32644013 https://news.ycombinator.com/item?id=32644013 - Aug 2022 (50 comments) Solaris: ESA Says Space-Based Solar Power Is a Real Option - https://news.ycombinator.com/item?id=32513122 https://news.ycombinator.com/item?id=32513122 - Aug 2022 (5 comments) On beaming solar power from low earth orbit - https://news.ycombinator.com/item?id=28426262 https://news.ycombinator.com/item?id=28426262 - Sept 2021 (86 comments) California utility bets on space-based solar power - https://news.ycombinator.com/item?id=28225254 https://news.ycombinator.com/item?id=28225254 - Aug 2021 (3 comments) $100M donation powers decade-long moonshot to generate solar-power from space - https://news.ycombinator.com/item?id=28106957 https://news.ycombinator.com/item?id=28106957 - Aug 2021 (3 comments) Beaming Down Space Solar – Air Force Research - https://news.ycombinator.com/item?id=27334259 https://news.ycombinator.com/item?id=27334259 - May 2021 (3 comments) UK government considers space-based solar power for 24/7 Solar Generation - https://news.ycombinator.com/item?id=26674956 https://news.ycombinator.com/item?id=26674956 - April 2021 (28 comments) A solar panel in space is collecting energy that could be beamed to anywhere - https://news.ycombinator.com/item?id=26262524 https://news.ycombinator.com/item?id=26262524 - Feb 2021 (5 comments) China wants to put a solar farm in space by 2025 - https://news.ycombinator.com/item?id=19190620 https://news.ycombinator.com/item?id=19190620 - Feb 2019 (59 comments) Scientists are working on space-based solar panels - https://news.ycombinator.com/item?id=10310307 https://news.ycombinator.com/item?id=10310307 - Oct 2015 (11 comments) Harvesting solar power in space and sending it back to Earth - https://news.ycombinator.com/item?id=6294565 https://news.ycombinator.com/item?id=6294565 - Aug 2013 (80 comments) Space Solar Power System - https://news.ycombinator.com/item?id=2197108 https://news.ycombinator.com/item?id=2197108 - Feb 2011 (11 comments) Will the stars align for space-based solar power? - https://news.ycombinator.com/item?id=698859 https://news.ycombinator.com/item?id=698859 - July 2009 (6 comments) New Company Looks to Produce Space Based Solar Power Within a Decade - https://news.ycombinator.com/item?id=487316 https://news.ycombinator.com/item?id=487316 - Feb 2009 (6 comments) ... and what the hell: A Material That Throws Heat into Space Could Soon Reinvent Air-Conditioning - https://news.ycombinator.com/item?id=15249089 https://news.ycombinator.com/item?id=15249089 - Sept 2017 (25 comments) Efficient Air-Conditioning Beams Heat into Space - https://news.ycombinator.com/item?id=15176721 https://news.ycombinator.com/item?id=15176721 - Sept 2017 (187 comments) Material Cools Buildings by Sending Heat into Space - https://news.ycombinator.com/item?id=8684647 https://news.ycombinator.com/item?id=8684647 - Dec 2014 (18 comments) Cooling panel sends excess heat back into outer space - https://news.ycombinator.com/item?id=5556564 https://news.ycombinator.com/item?id=5556564 - April 2013 (14 comments)

fourseventy 4y ago

I never understood the point of this. Energy is already beaming to earth from space. Much easier to just let it get to us on earth and collect it there.

deleted 4y ago
[deleted]
henearkr 4y ago
Less space constraints in orbit, also this is technology required for the next step, a Dyson Sphere, which allows to gather much much more energy.

didgetmaster 4y ago

Assuming that this technology can advance enough to become practical; are there orbits a satellite can take where it could collect sunlight continuously (i.e. it is not in the Earth's shadow very much) yet still be over a spot where it could deliver energy to a desired point on the Earth for a significant amount of time?

0x0203 4y ago
You can look up sun-synchronous orbits; orbits that are mostly polar, but can be set up to continuously face the sun and without ever going into the earth's shadow. For continuous power delivery to a single ground station from such an orbit, you'd need several satellites. (If you remove the requirement to never be in shadow, but just mostly never, there are quite a few orbits that could be set up.) Geo-synchronous orbits would always be stationary above a single point on the earth's surface and could therefore potentially get away with just one solar collector, but you are guaranteed to be in shadow at some point and taking up that much space in the very precious geo-orbit is unlikely.

kaiju0 4y ago

This has been researched and found impractical. First you have power conversions solar > electric > microwave > electric. Then the microwave transmission receiver has to grow at the square of the distance. Receivers need to be huge on the order of kilometers. Also to be stationary to the ground the satellites need to be in geo orbit making the distance huge. What am I missing?

drewbeck 4y ago
The vision and dedication of a team of Caltech scientists
choonway 4y ago
competition from china. don’t want to fall behind like with the hypersonics and rail guns

plasmatorch 4y ago

I worked on this project a few years back, on the power transmission bits. It's pretty cool from the engineering side; the mechanics need to be very light, and unfold into a large area. The beaming part is just a large phased array. The hardest bit is likely high efficiency, cost effective PV cells that can survive in space, but this is a field that Atwater has been in a long time, and is very, very good at.

kumarvvr 4y ago
Any info on system capacity and efficiency?
- plasmatorch 4y ago
  IIRC, it took about 50~100 W from a power supply to beam ~2.5W to a target antenna array, but that was fairly early on, so it's likely better now.
pencilguin 4y ago
Probably a laser would be a much better power transmission method: shorter wavelengths spread out less. You would pick a wavelength that PV panels on the ground convert most efficiently, and pump the laser cavity with focused sunlight, directly. No fooling with PV panels, then. Monochromatic light can be converted via PV with little loss. Mirrors to focus sunlight weigh practically nothing. Made of alternating layers of different index of refraction, of thickness according to the pumping wavelength, they reflect only that wavelength, and let the rest pass through. So, the laser cavity doesn't get hot, an important detail in space where cooling is hard. You would arrange so the laser light intensity is no more than of sunlight, for safety. Of course it wouldn't do much good in the daytime, but would work at night and in winter. Just, not so good through clouds.
- pipodeclown 4y ago
  Isnt this really a question the reflectivity and amount of absorption in the atmosphere of the wavelength you're using?

AtlasBarfed 4y ago

Amazing Bond plot: Someone gets ownership of Antarctica, uses Solar panels to raise the temperature of Antarctica and melt all the snow cover, gains control of an entire new continent. Also Gundam 0083 had the solar system II superweapon, which was just mirrors. But fundamentally, isn't this increased insolation and on a large scale would accelerate warming? Man, couldn't we use a bunch of mirrors to locally warm northern climates in Siberia, Antarctica, etc... I wonder if that would be worth it.

sakitgigi 4y ago

if you can get 100wph from 1m2 of solar panel on earth, how much electricity can you get from space for an equivalent 1m2 space panel ? i read the no night argument, so if earth panel gets usable 8hr per day, the space panel automatically gets 3x gains, no ?

drewbeck 4y ago
The article says 8x all in

wrycoder 4y ago

This same tech was on the cover of a 1971 IEEE Spectrum magazine. I don’t see any advancement since then.

LargoLasskhyfv 4y ago
Roland Emmerich's first from 1984! https://en.wikipedia.org/wiki/The_Noah%27s_Ark_Principle https://en.wikipedia.org/wiki/The_Noah%27s_Ark_Principle
MichaelZuo 4y ago
100 km of atmosphere in the way of any 'beaming' makes the economics unviable even with recent drops in launch prices. It will likely have to be assembled in space from materials mined in space to ever work out.
- avmich 4y ago
  Microwaves pass through atmosphere with negligible losses.
  - MichaelZuo 4y ago
    The losses certainly are not negligible, they're >> 10%.
    - fnordpiglet 4y ago
      That’s why Bruce banner was experimenting with gamma rays. It’s a shame what happened to him.
    - e12e 4y ago
      Infrared laser in wavelengths between 8 and 13 micrometers? The inverse of radiative cooling? https://news.ycombinator.com/item?id=15176721 https://news.ycombinator.com/item?id=15176721
- guyzero 4y ago