Author Topic: Solar Power Satellites  (Read 29392 times)

Offline MP99

Re: Solar Power Satellites
« Reply #60 on: 10/17/2014 07:59 AM »


Should use lasers and find a customer that needs a lot of power and is willing to pay a LOT more than $0.10/kWh and lives above the clouds and could use a system at the hundreds of kW range to start.

Cloud servers in the clouds.

Dunno, that perigee sounds a bit low. ;-)

Cheers, Martin

Offline Asteroza

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Re: Solar Power Satellites
« Reply #61 on: 10/17/2014 08:15 AM »
Should use lasers and find a customer that needs a lot of power and is willing to pay a LOT more than $0.10/kWh and lives above the clouds and could use a system at the hundreds of kW range to start.

Cloud servers in the clouds.

Well, Facebook/Ascenta or Google/Titan Aerospace have solar electric HALE drone projects. Tuned solar cells for receiving laser light from above is not entirely crazy (see Lasermotive UAV demos). Good pointing accuracy isn't necessary if the spot is wide and at light sunburn levels of power...

Offline SICA Design

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Re: Solar Power Satellites
« Reply #62 on: 10/17/2014 08:48 AM »
How much would a HESPeruS satellite cost? (not including launch costs as obviously that's highly dependent on how cheap Skylon and/or SpaceX reusability turn out to be in actual practice...)
To estimate the future cost (1-2 decades hence) of materials and manufacture is incredibly difficult and prone to inaccuracy.

What I can state is that the HESPeruS design uses very few types of component:

Almost the entire functionality is modular down to a 25mm scale - including photovoltaics (either concentrated multi-junction, or future thin fim, e.g. perovskite), dc to microwave conversion at <100mW levels (single CMOS ASIC) and micro-wave beam formation (dual crossed dipole / crossed elliptical antenna).

Combining 25,000 of these elements into a modular panel (~5m across), including several pilot beam receivers, allows coherent microwave beam formation and retro-directive steering. Up to 1 million panels would be necessary for a complete system delivering 1GW to the grid.

Getting costs down to economical levels will require extreme mass-production and automation, the same drive which has put powerful processing and microwave technology into peoples pockets, to be discarded as throw-away items after one or two years.

Offline SICA Design

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Re: Solar Power Satellites
« Reply #63 on: 10/17/2014 08:55 AM »
Should use lasers and find a customer that needs a lot of power and is willing to pay a LOT more than $0.10/kWh and lives above the clouds and could use a system at the hundreds of kW range to start.

Cloud servers in the clouds.

Well, Facebook/Ascenta or Google/Titan Aerospace have solar electric HALE drone projects. Tuned solar cells for receiving laser light from above is not entirely crazy (see Lasermotive UAV demos). Good pointing accuracy isn't necessary if the spot is wide and at light sunburn levels of power...

John Mankins is promoting space-based servers as a good means to kick-start Space Based Solar Power

http://www.nss.org/adastra/volume25/spsalpha.html

Offline SICA Design

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Re: Solar Power Satellites
« Reply #64 on: 06/07/2017 09:10 AM »
Including one notable and impending reversal, there are currently 191 signatories to the Paris Climate Agreement, all recognising the need to reduce man-made greenhouse gas emissions, due primarily to the combustion of fossil fuels. With widespread distrust and lack of nuclear power investment, there are few options which can replace the guaranteed baseload power provided by coal, oil and gas.

There is rapid and increasing uptake of both wind and solar power, but almost zero grid-scale storage necessary to overcome their unpredictable nature. In 2015, the three largest terrestrial solar photovoltaic farms provided (on-average) just 5 watts per square metre. This is similar for solar-thermal plants and less for wind-power.

To generate the 28 terrawatts predicted total world power requirement by 2050 (for a global population expected to peak below 10 billion), a massive increase in wind and solar will likely compete with food production for available land. However, there is a band located around the Earth from which we could extract all this power many-times over, beamed as biologically and ecologically benign microwaves, converted with over 90% efficiency to electricity (50% end-to-end efficiency), from which we can then meet all our energy needs.

We’ve known about this since the early 1970’s, and we have had daily demonstrations of the fundamental technology ever since the first geostationary communications satellite was placed in orbit. The only significant difference between a communications and a power satellite is the scale required to capture the majority of the beam.

From geosynchronous orbits, fundamental physics dictates a kilometre-scale transmit antenna to beam microwave power across 36,000 km of space, through the atmosphere during all weathers, to a multi-kilometre terrestrial receiving station (rectifying antenna or “rectenna”) – and do this without prohibitive losses. This is irrespective of how much power, so it better be in the region of gigawatts (GW) delivered, to justify the massive transmitter, which still leads to a peak beam intensity weaker than sunlight at the ground (so forget those “space-weapon” fears).

Nearly all proposals take a high-level systems approach, splitting the satellite into the antenna facing the Earth and the collector facing the Sun. This inevitably leads to a complex kilometre-scale 3D structure with continuously moving parts as the satellite traverses its orbit. In 1971, one proposed 5 GW solar power satellite (SPS) massed 34,000 tonnes, with typical concepts today still around 5,000-10,000 T/GW.

HESPeruS (JBIS, Vol. 69, pp 127-138, 2016 http://jbis.org.uk/paper.php?p=2016.69.127 ) is a proposal which eliminates the moving parts in-favour of a solid state design. Its essentially-flat and highly modular structure reduces mass to around one tenth that of competing designs, and simplifies robotic orbital construction - but that orbit needs to be a highly elliptical (Molniya) orbit in order to both face the Sun and stay within its beam steering limits.

Offline SICA Design

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Re: Solar Power Satellites
« Reply #65 on: 06/07/2017 09:22 AM »
IN THE INTERESTS OF PUBLIC DISCLOSURE:

CASSIOPeiA – Constant Aperture, Solid State, Integrated, Orbital Phased Array


The recent invention of CASSIOPeiA (patent applied for), has realised a scalable design which can work in any orbit, capable of both directly facing the Sun and beaming continuously through 360 degrees, solving the beam steering issues of a planar array without any mass penalty.

CASSIOPeiA deploys from a highly compact stowed form, into a gossamer large-scale helical array, having sufficient self-rigidity to support itself in microgravity. Unlike a parabolic dish (for example), there is no need to maintain a perfect rigid geometry in the presence of varying thermal expansion, nor precision pointing accuracy. Instead, the power beam is formed and locked on target by measuring the spherical wavefront of a pilot signal emitted by the terrestrial station, synchronously sampled by numerous receivers across the orbital array, with phase measurements reversed in time to generate the coherent power beam.

Key to the design are the half-wavelength spaced elements, which combine highly efficient concentrated photovoltaics with a triple antenna configuration - able to electronically steer a shaped radiation pattern (cardioid) through 360 degrees. This combination of steerable element pattern and the constant aperture (cross-sectional area as seen from the Earth) of a helical surface results in a high quality beam, matching that of an equivalent planar array’s ideal boresight direction, but invariant throughout 360 degrees azimuth, combined with +/-55 degrees elevation (elevation limits where peak intensity drops by 3dB, “azimuth” and “elevation” with respect to the rotational axis of the array).

This integration allows the flexible substrate to provide mechanical support, electrical interconnect and simplified thermal management – functions typically assigned to distinct large-scale structures in other SPS proposals.

By matching CASSIOPeiA’s RF aperture to the area of intercepted sunlight, the design is completely scalable from 200 kW to 600 MW predictable delivered power. Examples:

1)   A pseudo-satellite measuring 34m across, massing 200-400kg and situated at 20 km altitude inside the transparent envelope of a station-keeping stratospheric blimp (see Thales Stratobus for a near-term example), providing 200 kW continuous power throughout daylight hours.
2)   A constellation of 300m diameter, 20-40 tonne satellites following offset Sun-synchronous 2-hour orbits, skipping over Earth’s shadow to provide near-continuous power at 20 MW. Each satellite conceivably launched and deployed as a single payload.
3)   Similar 400m diameter, 33-66 T satellites delivering 33 MW from 2-hour 24-minute Sun-synchronous orbits.
4)   A constellation of 5 satellites, each 650 m diameter, massing 90-180 T, delivering 90 MW to multiple northern latitude sites from 3-hour, Sun-synchronous elliptical orbits. Rectenna utilisation is > 95% at 45 degrees latitude, >98.5% at 60 degrees (see figure).
5)   A single 1.4 km diameter geosynchronous satellite, massing 430 - 860 T 600 – 1200 T, delivering 430 600 MW with >99% utilisation.

All these examples provide surface beam intensities no-greater than one-quarter sunlight, intrinsically safe to wildlife, with average delivered surface power densities ten times greater than the current best wind and terrestrial solar sites. The option to safely and aesthetically combine rectenna sites with agriculture (by raising the mesh-like rectenna several metres above the ground) removes the potential future conflict between food and power production.

[Edit: correction to GSO example 5, for delivered power, not total RF power]
« Last Edit: 06/10/2017 04:26 PM by SICA Design »

Offline TrevorMonty

Re: Solar Power Satellites
« Reply #66 on: 06/07/2017 06:05 PM »
Unfortunately all current solar installations can't provided base load.
For SPS to every be viable they need to be built in space from space materials eg moon or asteriods. The technology to do this is evolving but we have long way to go.
The other critical item is pilot satellite to prove beaming high quatities of power back is possible.

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Offline Robotbeat

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Re: Solar Power Satellites
« Reply #67 on: 06/07/2017 06:21 PM »
Unfortunately all current solar installations can't provided base load.
For SPS to every be viable they need to be built in space from space materials eg moon or asteriods. The technology to do this is evolving but we have long way to go.
The other critical item is pilot satellite to prove beaming high quatities of power back is possible.

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Oft-repeated myth. Terrestrial photovoltaics can provide baseload if oversized (to provide power during cloudy days) or geographically diversified and coupled with batteries.

Additionally, I don't think building SBSP with space resources is required (or even competitive) if you get launch costs low enough.
« Last Edit: 06/07/2017 06:25 PM by Robotbeat »
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Offline Asteroza

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Re: Solar Power Satellites
« Reply #68 on: 06/07/2017 11:27 PM »
IN THE INTERESTS OF PUBLIC DISCLOSURE:

CASSIOPeiA – Constant Aperture, Solid State, Integrated, Orbital Phased Array



I think I get the design, but is the helix central axis actively pointed at the sun, or are you willing to take the off-angle power efficiency loss to utilize passive pointing? Like Mankin's SPS-ALPHA, unless you have a lot of good orientation/beaming pictures, people will have trouble visualizing the arrangement and usage. If passive, would you also be using an upward tether mass to gravity gradient stabilize the nadir pointing of the phased array, or will you also be using active means to roll the helix to improve pointing at specific ground targets?

The physical arrangement is unique and very interesting as a solution to the power slip ring bearing issue that plagues classic SPS designs. Recent designs like the NASA butterfly tend to end up with a GEO fixed sandwich panel design of sorts, though SPS-ALPHA does the psuedo-cone arrangement, and the recent FISO presentation on Z step sandwich panel module research had a rather interesting central stepped cone arrangement replacing the traditional fixed flat disk of the NASA butterfly design (which is conceptually similar to this helix arrangement even if visually not so). Nice to see more people thinking beyond rectilinear 3D.

I guess you could also call it a heliogyro style of sorts...

But how does the GEO case work without relay mirrors like the NASA butterfly design, for a single satellite design? Wouldn't a 24 hour sun tracking spin to keep the PV panels lit also point the phased array primary axis so far off orthogonally that you would get terrible transmission efficiency?
« Last Edit: 06/07/2017 11:36 PM by Asteroza »

Offline QuantumG

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Re: Solar Power Satellites
« Reply #69 on: 06/08/2017 01:08 AM »
I really don't care if terrestrial solar is better than solar power satellites.

Can we talk about the topic please?

34,000 tons sounds like fun. 100 ITS flights or 200 mini-ITS?



Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline TrevorMonty

Re: Solar Power Satellites
« Reply #70 on: 06/08/2017 03:23 AM »
IN THE INTERESTS OF PUBLIC DISCLOSURE:

CASSIOPeiA – Constant Aperture, Solid State, Integrated, Orbital Phased Array



I think I get the design, but is the helix central axis actively pointed at the sun, or are you willing to take the off-angle power efficiency loss to utilize passive pointing? Like Mankin's SPS-ALPHA, unless you have a lot of good orientation/beaming pictures, people will have trouble visualizing the arrangement and usage. If passive, would you also be using an upward tether mass to gravity gradient stabilize the nadir pointing of the phased array, or will you also be using active means to roll the helix to improve pointing at specific ground targets?

The physical arrangement is unique and very interesting as a solution to the power slip ring bearing issue that plagues classic SPS designs. Recent designs like the NASA butterfly tend to end up with a GEO fixed sandwich panel design of sorts, though SPS-ALPHA does the psuedo-cone arrangement, and the recent FISO presentation on Z step sandwich panel module research had a rather interesting central stepped cone arrangement replacing the traditional fixed flat disk of the NASA butterfly design (which is conceptually similar to this helix arrangement even if visually not so). Nice to see more people thinking beyond rectilinear 3D.

I guess you could also call it a heliogyro style of sorts...

But how does the GEO case work without relay mirrors like the NASA butterfly design, for a single satellite design? Wouldn't a 24 hour sun tracking spin to keep the PV panels lit also point the phased array primary axis so far off orthogonally that you would get terrible transmission efficiency?
Mirrors can be aluminum or another metal, if produced in space then there won't be any oxidisation. Plus it can be very thin and lite.



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Offline Robotbeat

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Re: Solar Power Satellites
« Reply #71 on: 06/08/2017 04:02 AM »
I really don't care if terrestrial solar is better than solar power satellites.

Can we talk about the topic please?

34,000 tons sounds like fun. 100 ITS flights or 200 mini-ITS?
That's the thing about ITS:

Musk may think SBSP is dumb, but ITS actually gives it a shot at working.

And same with Bezos' New Armstrong, if it's competitive with ITS. And Bezos might actually BUILD it, since:
1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Stan-1967

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Re: Solar Power Satellites
« Reply #72 on: 06/08/2017 04:17 AM »

1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).

That lucky Bezos guy is going to retire as a millionaire if he jumps into SBSP.

Offline Robotbeat

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Re: Solar Power Satellites
« Reply #73 on: 06/08/2017 04:31 AM »

1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).

That lucky Bezos guy is going to retire as a millionaire if he jumps into SBSP.
Ya can't take it with you...

But I think you underestimate how rich Bezos is.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline RocketmanUS

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Re: Solar Power Satellites
« Reply #74 on: 06/08/2017 05:10 AM »
I really don't care if terrestrial solar is better than solar power satellites.

Can we talk about the topic please?

34,000 tons sounds like fun. 100 ITS flights or 200 mini-ITS?
That's the thing about ITS:

Musk may think SBSP is dumb, but ITS actually gives it a shot at working.

And same with Bezos' New Armstrong, if it's competitive with ITS. And Bezos might actually BUILD it, since:
1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).
Solar power for use in space for industry use. Perhaps in the future solar from space for use on Earth might work , but for now I would say in space use. Products made in space for space use and for Earth.

Offline Robotbeat

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Re: Solar Power Satellites
« Reply #75 on: 06/08/2017 05:51 AM »
I really don't care if terrestrial solar is better than solar power satellites.

Can we talk about the topic please?

34,000 tons sounds like fun. 100 ITS flights or 200 mini-ITS?
That's the thing about ITS:

Musk may think SBSP is dumb, but ITS actually gives it a shot at working.

And same with Bezos' New Armstrong, if it's competitive with ITS. And Bezos might actually BUILD it, since:
1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).
Solar power for use in space for industry use. Perhaps in the future solar from space for use on Earth might work , but for now I would say in space use. Products made in space for space use and for Earth.
Not buying it unless you can be SPECIFIC. What would move a significant amount of industrial activity off planet? How many Gigawatts?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline RocketmanUS

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Re: Solar Power Satellites
« Reply #76 on: 06/08/2017 06:18 AM »
I really don't care if terrestrial solar is better than solar power satellites.

Can we talk about the topic please?

34,000 tons sounds like fun. 100 ITS flights or 200 mini-ITS?
That's the thing about ITS:

Musk may think SBSP is dumb, but ITS actually gives it a shot at working.

And same with Bezos' New Armstrong, if it's competitive with ITS. And Bezos might actually BUILD it, since:
1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).
Solar power for use in space for industry use. Perhaps in the future solar from space for use on Earth might work , but for now I would say in space use. Products made in space for space use and for Earth.
Not buying it unless you can be SPECIFIC. What would move a significant amount of industrial activity off planet? How many Gigawatts?
NEA and Lunar mining, product for space exploration and living off Earth. Why make it on Earth when it would be used off Earth. For Earth based use, environmental issues making a product on Earth that could be made in space or mined in space without the environmental impact here on earth.

So that is how I would see large solar power used in space.

Offline SICA Design

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Re: Solar Power Satellites
« Reply #77 on: 06/08/2017 10:05 AM »
IN THE INTERESTS OF PUBLIC DISCLOSURE:

CASSIOPeiA – Constant Aperture, Solid State, Integrated, Orbital Phased Array



I think I get the design, but is the helix central axis actively pointed at the sun, or are you willing to take the off-angle power efficiency loss to utilize passive pointing? Like Mankin's SPS-ALPHA, unless you have a lot of good orientation/beaming pictures, people will have trouble visualizing the arrangement and usage. If passive, would you also be using an upward tether mass to gravity gradient stabilize the nadir pointing of the phased array, or will you also be using active means to roll the helix to improve pointing at specific ground targets?

Ideally (at GSO), the helix axis is normal to the ecliptic. A dielectric mirror inclined at 45 degrees allows a CPV chip to be mounted on the same substrate as the electronics (with radiation shielding provided by the secondary  Kohler concentrator), and may be integrated with the triple-antenna arrangement which generates the steerable cardioid pattern. Thermal management is by simple heat spreading by the conductive layers within the substrate.

The comparison here is with a standard square planar array (having side D, no rear reflector/absorber) having the same number of RF elements, power and spacing. The side-view RF aperture of the array equals its solar collecting area, and is given by 2*D^2/pi

The RF surface intensity animation is modelled for a slightly larger array, as it rotates through 360 degrees of orbit (as seen from Earth), continuously and directly facing the sun (one physical rotation/year).

As can be seen, from a mass distribution POV, the design is rotationally symmetric (so no GG stabilisation). Attitude and maneuvering control is still required, though a means of using passive sunlight pressure to aid sun-pointing is being investigated.
« Last Edit: 06/08/2017 10:45 AM by SICA Design »

Offline Robotbeat

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Re: Solar Power Satellites
« Reply #78 on: 06/08/2017 01:21 PM »
I really don't care if terrestrial solar is better than solar power satellites.

Can we talk about the topic please?

34,000 tons sounds like fun. 100 ITS flights or 200 mini-ITS?
That's the thing about ITS:

Musk may think SBSP is dumb, but ITS actually gives it a shot at working.

And same with Bezos' New Armstrong, if it's competitive with ITS. And Bezos might actually BUILD it, since:
1) Bezos is way richer than Musk and will still be super rich after developing New Armstrong and
2) Bezos doesn't explicitly think SBSP is dumb; he talks a lot about moving industry off-planet, and energy production is one of (if not THE) largest.

Bezos could actually afford to finance a few full-sized SBSP stations himself, especially if he finds clever ways of leveraging his own cash (as all self-made billionaires tend to do).
Solar power for use in space for industry use. Perhaps in the future solar from space for use on Earth might work , but for now I would say in space use. Products made in space for space use and for Earth.
Not buying it unless you can be SPECIFIC. What would move a significant amount of industrial activity off planet? How many Gigawatts?
NEA and Lunar mining, product for space exploration and living off Earth. Why make it on Earth when it would be used off Earth. For Earth based use, environmental issues making a product on Earth that could be made in space or mined in space without the environmental impact here on earth.

So that is how I would see large solar power used in space.
No, still not specific enough. Again, what product or mineral or whatever are you proposing to make industrially off-Earth that significantly would reduce impact on Earth, and how many Gigawatts does this replace?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Online gongora

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Re: Solar Power Satellites
« Reply #79 on: 06/08/2017 10:34 PM »
Split recent earth vs. space solar posts into separate thread:
Earth Solar vs. Solar Power Satellites