SPS Mechanical Solar Power Satellite Steampunk Vision

tahanson43206 · 2024-10-03 09:57:50

This topic is inspired by a suggestion from Calliban, that a mechanical (non-electronic) Solar Power Satellite might be not only feasible, but competitive with popular silicon solar panel vision.

Solar panels are successful in space applications, and they have been for many decades now.

The vision of Calliban would collect power from the flow of thermal energy between a hot plate facing the Sun, and a cold plate facing deep space, where 4 degrees Kelvin is the (approximate) temperature of the background radiation.

In the vision of a mechanical energy capture system, an efficiency of 50% might be possible.

This topic is offered for those NewMars members who share an interest in non-electronic systems, and who are willing to stretch to imagine a gigantic SPS that uses no electronics at all for it's primary function.

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tahanson43206 · 2024-10-03 09:58:23

This post is reserved for an index to posts that may be contributed by NewMars members over time.

Post #6: kbd512 re masers for power transmission:
https://newmars.com/forums/viewtopic.ph … 76#p226976

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tahanson43206 · 2024-10-03 10:54:23

This topic ** should ** generate some interest outside the small community of active NewMars participants. If I'm right, and there are folks ** out there ** who would like to engage with Caliban in developing a mechanical SPS concept, please see the Recruiting Topic for procedure.

A well designed mechanical SPS would work ** really ** well closer in to the Sun, since the deep space heat sink is available there and the solar flux is so much greater.

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Calliban · 2024-10-03 16:33:35

When O'Neill first described SPS, they were steam plants. Only later was the concept ungraded to PV. But the two systems would have about the same power density in full sun. But thermodynamic plants would be mostly steel construction, whereas PV requires polysilicon. Given the scale of equipment needed to make polysilicon, it isn't clear to me that PV gives better results than a thermodynamic plant. It is much easier to make carbon steel than semiconductor grade silicon. And concentrating mirrors and radiators will be no heavier than PV panels.

So why bother trying to make PV? It makes more sense on Earth, because PV continyes to produce power under diffuse light. It is also easier for small distributed operations, because it has no moving parts. But those advantages count for much less with a multi-GW space solar power station.

Last edited by Calliban (2024-10-03 16:35:44)

tahanson43206 · 2024-10-03 18:07:02

For Calliban re #4

Thanks for the inspiration to refresh memory of those heady days when visions of solar power satellites were in the air, and humans had not yet landed on the Moon. The suggestion that mechanical systems might have been considered early is intriguing and I intend to do a bit of research. In the mean time, I do feel that it is reasonable to remember Peter Glazer, who is believed to be the first human to secure wide publicity for the SPS concept.

I found an article in Physics World that i hope to paste into this topic, but it's on a different computer. The essential information is that Glaser's concept used solar panels when the concept was first published in 1968.

No doubt patents were filed with SPS designs, so I'll look for evidence of those.

Regardless of what may have been the case in the past, the present is here with fresh opportunities for your vision to receive attention, and hopefully some funding to prove the concept would actually work.

A very small prototype heat engine should be able to prove your concept is valid, and that the efficiency of 50% might be achieved.

I'll make an effort to find any evidence of prior work in this specific discipline. In the mean time 70+ years have gone by, and humans know much more than we did in those early days.

Please translate your vision into a sketch of a prototyple that can be build and deployed on a Falcon 9 or one of the light lifters on the market these days.

(th)

tahanson43206 · 2024-10-03 18:12:11

This post is intended to capture a bit of the early history of the SPS idea, as we embark upon a newly refreshed vision of a mechanical solution rather than an electronic one.

https://physicsworld.com/a/space-based- … rgy-needs/

Space dreams
The original concept of solar power from space was dreamt up in 1968 by Peter Glaser, a US engineer at the consultancy Arthur D Little. He envisaged placing a huge disc-shaped satellite in geostationary orbit some 36,000 km above the Earth (Science 162 857). The satellite, roughly 6 km in diameter, would be made of photovoltaic panels to collect sunlight and convert it into electrical energy. This energy would then be turned into microwaves using a tube amplifier and beamed to Earth via a 2 km-diameter transmitter.
It’s the only form of green, renewable energy with the potential to provide continuous, baseline electrical power.
Chris Rodenbeck, US Naval Research Laboratory
The beauty of microwaves is they don’t get absorbed by clouds here on Earth and so would pass largely (though not totally) unhindered through our atmosphere. Glaser envisaged them being collected by a fixed antenna 3 km in diameter, where they would be converted into electricity for the grid. “Although the use of satellites for conversion of solar energy may be several decades away,” he wrote, “it is possible to explore several aspects of the required technology as a guide to future developments.”
The initial reaction was positive in at least some quarters, with NASA awarding Glaser’s company, Arthur D Little, a contract for further study. Over the years, however, the conclusions of subsequent studies into space-based solar power have ranged from cautiously positive to outwardly negative.

All members of NewMars forum are welcome to assist with research. We are looking for any evidence that anyone seriously considered a non-photovoltaic method of capturing solar power.

*** After reading the entire article, which covers current work as well as historical designs, I can report that the authors included no mention of non-photovoltaic solutions. What they spent a lot of time on is design for continuous service without moving parts.

As near as I can tell, the field is wide open for an inventor who can show that a non-photovoltaic solution is both practical and competitive.0

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tahanson43206 · 2025-10-08 16:55:11

I'd like to bring this topic idea back into view. Calliban inspired this topic with his vision of a mechanical system to capture solar energy and convert it to electricity. The idea still has appeal. The machinery required would need lubrication and maintenance. I am hoping that Calliban (or anyone who might like the idea) will investigate further. The quiet reliability of photoelectric cells is certainly an argument in their favor.

I wonder if a Stirling cycle device might work as well and require a bit less maintenance?

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kbd512 · 2025-10-11 04:14:36

A key technology for solar power satellites, only now in its infancy, is room temperature masers- coherent microwave power transmission devices. Synthetic diamond wafers are capable of transmitting RF power without significant loss of beam coherency over great distances. Imperial College London and Northumbria University have done quite a bit of the civil work on such devices, all of it within the past 15 years or so. We can think of this tech as the microwave frequency equivalent of a laser, but without the significant efficiency losses that still plague solid state lasers. The insistence on using solid state electronic devices is why high power military lasers remain relatively impractical. Lasers with exceptional power outputs measured in megawatts have been available for many decades, but require complex chemical processes that need to be managed by qualified engineers to prevent the devices from exploding in operation. For obvious reasons, the military didn't want to contend with that kind of complexity, in much the same way that virtually all military missiles use solid rocket motors vs liquids.

Traditional masers were experimented with from the 1950s to 1970s for military applications related to sensing, targeting, and communications, but unfortunately required deeply cryogenic temperatures, and were mostly scientific curiosities due to their special operating requirements, despite repeated attempts to further develop the tech for military purposes. I watched a couple of TED Talks and tech presentations on this new class of devices on YouTube a few months back. Prior to that, I never knew room temperature maser devices existed.

I think one of our first Mars probes was able to transmit pictures from Mars to Earth because a maser-based deep space receiver on Earth was so selective that the paltry RF power output from the probe's radio could be tuned-into well enough to capture the data it sent back. However, that device had to be operated near absolute zero using LH2 or LHe, IIRC.

In the near-future, I think these devices will see use as low-cost / low-power microwave band radar systems for space probes / light aircraft / missiles / drones. Longer-term, their application to solar power satellites is compelling. A maser's ability to significantly reduce the size of ground-based rectennas means individual vehicles could be effectively powered from orbit. Room temperature maser tech has the potential to dispense with some of the heavy batteries and solar arrays in favor of beaming power.

One particularly interesting presentation from Northumbria related to using a LED for the input power driving a room temperature maser device. If we can almost directly create coherent microwave radiation using photonic input power that would be a real game changer for orbital power stations.

Anyway...

As power requirements scale up, there's quite a difference in terms of overall design, total system complexity, and materials energy input between square kilometers of semiconductors vs mirrors or fiber optics. Mirrors can be scaled-up in a more or less linear in nature, especially when the photonic power is being thermalized into a central receiver tube. For a mirror with 200m^2 vs 20m^2 of surface area, the components used in the plant design don't change substantially. The cost differential is mostly a function of the mass of materials produced and transported. In terms of total plant cost per Watt, there's an economy of scale to be had by using thermal power systems.

This is not the case for purely electronic power systems where every component in the system is some type of electronic device. The differences in voltages and amperages dictate the use of entirely different electrical and electronic components to efficiently transmit and condition the power from the periphery of an array, back to a centralized collection / distribution station. The semiconductor wafers used to generate the power don't change, but transmitting 10X to 100X more electrical power back to a centralized point, presumably for microwave power transmission to a ground-based rectenna, involves changing everything else. The wiring gauges must change, insulation requirements increase to prevent arcing since a significant voltage increase is the primary means to reduce resistance losses during power transmission while minimize wiring mass, step-up / step-down transformers must also change, and the array control system changes to account for many more array elements and system components. A control system appropriate for a 100kWe to 1MWe array is inappropriate for a 1,000MWe array.

For a high temperature thermal system with a centralized receiver tower and Supercritical CO2 gas turbine turning an electric generator, concentrating 10MWth vs 1,000MWth requires a direct scale-up of the same basic plant components. The count and/or surface area of the mirrors changes substantially, but a thermal power plant doesn't involve a multitude of wiring runs with different gauges, power inverters, step-up transformers, electronic control and monitoring systems, etc.

If a photonic-to-maser power system ever becomes practical, then we can dispense with thermal-to-electrical conversion as well, using only fiber optics to collect power from the Sun, special solar-pumped diodes which directly convert (~35% efficient) the photonic power to feed the maser, and then transmit it as RF power to ground-based power terminals, for conversion to electrical power by the powered device. Photovoltaic-to-LED-diode is far less efficient, typically below 10%. Masers can be around 35% efficient over millimeter wavelengths useful for power transmission through atmospheric water vapor. Here on Earth, we might use such tech to power ships at sea. Some people will fixate on the apparent lack of efficiency, but the figure that matters is the ability to continuously remotely power an enormous machine, such as an ocean-going cargo ship, or perhaps a train on Mars, without enormous quantities of onboard energy storage, ground-based power generation and distribution infrastructure, or operational problems arising from intermittent power availability.

The most obvious first use case for a multi-gigawatt maser-based power satellite is thermal power transfer to boost the orbits of satellites and spacecraft in lower orbits. A power sat would save the most money by powering vehicles from the launch pad using simplistic Hydrogen-based heat engines, ones requiring no oxidizer mass, then to propel heavy payloads to higher orbits, and ultimately to achieve escape velocity for interplanetary transfers. Decoupling the energy supply from the powered vehicle means very heavy payloads can be moved using only modest amounts of propellant.

One question I have, though, is if we can generate gigawatts of power in orbit, then why not consume it there for manufacturing purposes?

As we transition to optical computing devices that are anywhere between 1M and 10M times more efficient per compute operation, why not put those new AI data centers in orbit where they're co-located with a power source capable of delivering a near-direct power source for their consumption?

The Earth observation and military satellites are already doing a lot of onboard imagery processing prior to sending the data back to Earth, so drastically increasing their compute power using optical chips consuming direct / near-direct optical power from the Sun is the next logical step in their evolution. Maser-based synthetic aperture radar could provide HD video-like image resolution in almost any weather conditions. The X-band radars they already use are capable of centimeter resolution and easily pick up supposedly "stealthy" ships and aircraft, which are specifically supposed to reduce observability against X-band radar. The images are a little more "blurry" when compared to non-stealthy objects, yet clearly identifiable as to exactly what they are. These things won't be able to read the paper you have in your hand, but they will be able to discriminate between civil and military ships / aircraft / vehicles, discard non-essential information, clean up the images, and only return near-finished intelligence products for human assessment.

Since the military is already paying for a lot of this development, and the civil applications also benefit at the same time, why not ask Daddy Warbucks to help finance the power transmission and sensing tech we'll inevitably need when we settle Mars?

Those recon satellites are already dual-use, meaning an "ordinary" (but wealthy) civilian can pay for and request their imagery. The government paid to put them up there and pays to have priority on tasking, but apart from that almost anyone with money (provided they're not an enemy of the state) gets to benefit from them. All we'd be doing is giving them a gentle nudge in the direction they already want to go.

On that note, what about using power satellites in higher orbits to power observation satellites in lower orbits, and power relays transferring power from GEO to LEO or GEO to LEO to surface?

We could also use GEO power sats to "clean up" the lower orbits by delivering optical or maser power to de-orbit the junk using ablation, or perhaps even collect it for recycling since we already expended energy to put it up there in the first place.

GW Johnson · 2025-10-12 09:39:27

If power is beamed as a coherent bean, beam spread is very much reduced. A power density that is quite dangerous leaving the satellite is still rather dangerous 30,000 km away. So you have to aim the beam with utter reliability. This is an inherent phenomenon with coherent beams. We've seen it before, with both laser and maser.

You do not have that risk to mitigate, if you could use an extension cord "fat" enough not to lose very much in I^2*R losses. The problem with that concept is the materials from which to build it do not yet exist! I think I said that when I posed the concept in a post elsewhere on these forums. I used the words "manurium", "unbelievium", and maybe "unobtainium", when I wrote the post.

But once they do exist, one could use the alternate extension cord approach to lower the cost of that electricity further, by simplifying and eliminating so many safety controls and devices.

The danger posed by the extension cord is the same as that posed by a space elevator: what if the thing breaks? Part of it will fall to Earth, ultimately at very high speeds. So you have to build it to reliably not break, if you do it at all, no matter what the available materials are, in the future.

GW

Calliban · 2025-10-14 06:34:53

Isaac Arthur has released his latest video on space based data centres.
https://youtu.be/iLNrYwx0th0

The neat thing about this is that it obviates the need for transmission of power from an SPS to the ground. Power is used where it is generated. This is a product that can realistically be sold to Earth based customers for profit. There is huge and growing demand for it. The downsides are transmission delay - 0.1s to a satellite in GEO. Such a satellite would also probably need a manned presence.

Void · 2025-10-14 09:43:20

I got tired of putting more fins:

It seems quite reasonable to think to beam power with lasers from orbit or even better from mountain peaks next to shadowed craters.

Imaging a Aluminum Balloon with fins as high as a skyscraper, with fins that help protect from impactors. Oxygen at 333 mb should forma protective Oxide film as it always does so fire would not be a big problem.

In the basement a data center with radiation protection. Perhaps using a heat pump to heat the Oxygen and to provide coolant to the data center.

So, the shadowed craters might be very valuable for that.

Granted that there is time latency, but for some things that may not so much matter.

This could be modified for the Moon: https://newmars.com/forums/viewtopic.ph … 09#p234709
Quote:

From post #182:
I believe that this is going to be massively important: https://www.youtube.com/watch?v=m0tMViyxxcw
Quote:
At 18 He Took On Space Energy! Satellites, Lasers & the Next Frontier
Over The Horizon
The basic notion is power plants in orbit that send laser power to spacecraft.

So solar power on the outside rims of these craters or in orbit of the Moon perhaps.

Beam power from several mountain peaks to the data centers.

Again time latency issues, but for the Moon the compute would be rather local, and for the Earth for some applications it would still be useful.

The Moon materials and structure can provide many protective potentials, and of course materials for the making of structures.

Ending Pending

Last edited by Void (2025-10-14 09:53:09)

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#1 2024-10-03 09:57:50

SPS Mechanical Solar Power Satellite Steampunk Vision

#2 2024-10-03 09:58:23

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#3 2024-10-03 10:54:23

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#4 2024-10-03 16:33:35

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#5 2024-10-03 18:07:02

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#6 2024-10-03 18:12:11

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#7 2025-10-08 16:55:11

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#8 2025-10-11 04:14:36

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#9 2025-10-12 09:39:27

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#10 2025-10-14 06:34:53

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

#11 2025-10-14 09:43:20

Re: SPS Mechanical Solar Power Satellite Steampunk Vision

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