35 thoughts on “Space Solar Power”

  1. If we’re never going to have large-scale space nuclear power, then we’re going to have to learn to make really big solar arrays. Remember the 39-days-to-Mars VASIMR ships? You had a choice of a 600 ton reactor or 800 tons of solar arrays that basically covered two square kilometers. None of the space cadets I knew at the time, all of them claiming to be NASA and OldSpace employees, saw anything wrong with asking the taxpayers to shell out for a mile-long spaceship. Evidently the mundane giggle factor was beyond their ken.

    1. There’s a third possibility. We, and by “we” I mean the West, give up on high-energy civilization. We get to watch our grandchildren hunt rats by candlelight as we freeze to death in the dark. Our great-grandchildren will dismiss running water as a fairy tale. This is the future that environmentalists have been working so hard to bring us since the first Earth Day was arranged by a psychotic killer named Ira Einhorn.

  2. The antenna farms to receive the microwave beams are huge and based on what I remember about the frequencies for power transfer will be effected by rain squalls on a regular basis. The origin of the SPS was the arab oil embargo, not AGW, but the point was the same, find something – anything – that would validate spending huge amounts of money on space technology.

    For a small fraction of the money, new tech nuclear reactors could be tested out while using some media discipline to stop the fear mongering.

    1. The late Jerry Pournelle wondered how many solar power satellites we could have built with the money spent on the war in Iraq.

        1. Worth recalling that Pournelle’s novel (with Larry Niven) LUCIFER’S HAMMER had as its key narrative the quest to save the last nuclear power plant on the West Coast from a band of post-apocalyptic Luddite cannibals.

    2. The military is interested on space solar power for use at remote operating locations. In the outlying areas of Iraq and Afghanistan, delivering fuel for generators was one on the most dangerous jobs anyone could do. It got so bad that in some places, the had to deliver fuel using helicopters. I read that the price for fuel including delivery costs was over $50 per gallon. Space solar power for places like this could simplify the logistics tail and would be at a much smaller scale than something intended to be connected to a power grid. With good storage systems, the power wouldn’t need to be continuous.

        1. They’re likely thinking in terms of kilowatts, not megawatts. Lower power requirements and higher beam signal strength can reduce the size of the ground antenna.

          1. Even relatively small solar arrays or rectennas would be highly vulnerable to even small arms and mortars, which the jihadis have in abundance.

      1. As engineers, we naturally try to optimize a system before asking whether it serves a useful purpose. Elon Musk has talked about this trait we have.

        Applied here, instead of coming up with a better way to deliver energy to US military forces in the Korangal Valley, Afghanistan, maybe we should eliminate the problem instead of trying to optimize it. There are a range of untried option, everything from converting them all to Episcopalians, building a dam and turning it into a giant pay-fishing lake, to nuking it from orbit.

    3. Rain squalls.

      So you mean your electric power feed will get interrupted at the same time as Dish Network?

    4. When I was at DARPA, I had a contractor come in with an idea to use “eye-safe” wavelength lasers to beam SSP power to photovoltaic cells on the ground. The PV cell bandgap would be tailored to the laser wavelength to achieve ~80% conversion efficiency, without the focusing problems and attendant side-lobe losses of microwave transmission. The remaining problem of weather was not addressed. But there were other parts of the office looking at high-altitude balloon technology, so I sketched out an idea for a very large, flat balloon (made of concentric toroidal balloons of the same minor radius) topped with a PV farm that could receive the beamed power. The apparatus could be flown at an altitude of 70,000 feet, above any weather, and positioned over a battlefield. There it would be moored by Zylon ropes carrying high voltage DC power transmission lines to the ground. An outfit called Phillystran (today’s status indeterminate) at the time sold ropes made of the polymer Zylon which had a “hang length” (the length of rope suspended from the top which would not break under its own weight) of >450,000 feet, making the entire idea feasible.

      In the same capacity at DARPA, I became acquainted with a guy who ran a nuclear research facility. When I bounced the SSP idea for supplying power to forward military units off him, he didn’t consider the details of the idea itself much. But he said that he had approached the military with the idea of a small, truck-mounted, accelerator-driven nuclear power supply for forward bases. Such devices would cost two orders of magnitude less than SSPs to develop, deploy and operate. The reaction he got was the same as the reaction I got, and the reaction anyone else with an alternative to diesel will get. The military knows diesel generators, and the logistics of supplying them, and are confident in their reliability. And reliability is the sine qua non for keeping troops 1) alive, and 2) combat effective. Fifty bucks a gallon is chicken feed to ensure that, and the likely $1 billion to $100 billion needed to bring about the nuclear or SSP alternatives, respectively, gets you 20 million to 2 billion gallons of diesel to the front today, guaranteed.

      I doubt if this will get any traction.

      1. “And reliability is the sine qua non for keeping troops 1) alive, and 2) combat effective.”

        An important point to keep in mind.

      2. If I know my enemy’s military outpost is dependent on a balloon 70,000 foot up, sounds like an attractive target.

        1. But one that would, by design, be very hard to take out – and could lay down responsive fire of breathtaking proportion.

          Gotta remember, the platform could see everything for hundreds of miles around, and serve as an ultra-broadband communication relay center. In addition to defending itself, it could direct ground-based fire with high precision on an instant basis.

  3. “By 2025, China plans to demonstrate a 100-kilowatt solar power station in low Earth orbit.”

    Isn’t ISS a “100-kilowatt solar power station in low Earth orbit”

      1. Couldn’t they just reroute power from the warp nacelles to the main deflector array? ¯\_(ツ)_/¯

  4. If moon has mineable water, it would become a market from electrical power in Space.

    It also seems possible Starlink would evolve into creating a market for electrical power in space.

  5. Seems like a race between two tortoises. Modular compact nuclear reactors versus SPS for space power applications. I could see deployment of one or the other for the electrification of a Mars colony. So I can’t quite understand Elon’s reluctance to SPS given the big investments he’s already made in Tesla and Solar City. Unless he plans on opening up a nuclear power plant company he’ll need to seriously contemplate electrical power generation on Mars. Maybe he figures it’s easier to use the Sabatier Process and divert some of that methane and oxygen to use in fuel cells aa well as rocket fuel?

  6. Never liked the Solar-to-microwave idea. While I am sure it could be made fail-safe against accident, it could never be made safe against use by terrorists. Can’t be good for a populated city to be microwaved, can it?

      1. On Mars, if make Microwave lethal, would it have better energy conversion.

        On mars there no wild life, and you need radiation shielding for other reasons. So not lethal assuming one has a standard level radiation shielding- and one could be additional amounts shielding specifically for accidental exposure to the beamed Microwave.
        Or rather just from Space to surface, one use Microwave beaming from surface to surface- at higher levels then it’s done on Earth.

      2. Heck, the fundamental problem with implementation has been that the beam can’t be well concentrated without a truly epic transmitting station, just due to the way wave fronts, antennas, and mirrors work.

        1. Well, you build the “truly epic transmitting station” on lunar surface and launch the whole thing from lunar. Or just build huge chunks on lunar surface and launch the huge chunks from Moon and put together at GEO.

          That means the cost to build things on Moon has to be cheap and/or cost electrical power has to be cheap, so +40 years after commercial lunar water starts on the Moon.
          Or after lunar economy is + 1 trillion per year.

  7. Build the solar power plant on the Moon’s north pole. There are tall mountains there, that get sun light 24/7 365. Beam that power to relay satellites in GEO. Then beam that power to rectenna farms on Earth.

    Now the customers.
    1. The militarily.
    The militarily will purchase the power for over seas bases. No more oil for powering over seas bases.
    2. Third World countries.
    Create an organization based on Christian Childrens Fund, and other organizations. But this organization won’t be sending bags og wheat, or rice. They will hook up a village to electric power.
    They will also pay for the power needs of the people of that village.
    The amount of power that they will pay for however, is enough to power a pump for the village, and so that each house can have three electric lights, and a hot plate with two burners.
    If a person in the village wants more power than that, then he will have to pay the rest of the amount.

    3. Spaceflight companies, and airline companies.
    With spacebased solar power, we could develop lightcraft. This will allow the launching of SSTO spacecraft, and hypersonic airships that can travel at mach 5.
    Now Rand, suppose you want to fly to Washington D.C. You could get there in just one hour in a hypersonic airship. If you want to fly from New York City, to London England, it would take 84 minutes. Fly from Los Angelos to London, it would take 2 hours, and 24 minutes.
    So you could get to anywhere, in no time.

    So, the first world will get fast transportation, and the third world will get electric power delivered to all it’s villages, and clean drinking water. No longer would children would have to go out and chop down tree, gather wood, or cow chips. They could go to school, or work in sweatshop factories.
    You would then start seeing lower birthrates in the third world.

    1. “Build the solar power plant on the Moon’s north pole. There are tall mountains there, that get sun light 24/7 365. Beam that power to relay satellites in GEO. Then beam that power to rectenna farms on Earth.”

      I would say get lunar electrical power to about $1 per kw hour.
      Right now it’s about $100 per kw hour.

      If the Moon could have electrical power at $1 per Kw hour, we would need the Moon to have mineable water.
      You need water, to get a lower cost LOX plus you get the Hydrogen.

      If you split water on Earth, you toss out the oxygen and keep the hydrogen. On the Moon the oxygen is worth more than the Hydrogen.
      So for minable lunar water, one needs to be about to buy lunar water for about $500 per kg. It might work if it was $1000 per kg. And would better if could buy lunar for less than $500 per kg.
      With 9 kg of lunar water, it split into 8 kg of Oxygen and 1 kg of hydrogen. The hydrogen worth about 4000 per kg and LH2 might be $5000 per kg. The oxygen worth about $1000 per kg. Or 8000 for LOX and $5000 for the LH2 from 9 kg of water bought for $4500 or if water is $1000 per kg for water $9000.
      To make 1 kg of hydrogen requires about 75 kw hour x 100 = $7500
      So, 4500 + 7500 = 12,000
      8000 LOX, and 5000 LH2 = 13,000
      So generally have to be able to buy lunar water at $500 per kg, and try to get electrical power at $100 per kw hour or less and failure to to reach that, means LOX has to be more than $1000 per kg.
      And if LOX is much more than $1000 per kg, you probably can’t export LOX to low lunar orbit. And if doing that, it could be double as much in terms of price.
      Your main problem is selling enough rocket fuel per year- or you go bankrupt. So I would say within 5 years, out has to be selling about 1000 tons of rocket fuel per year. First year could be less than 100 tons in first year, but within 2 years better be doing +200 tons per year, and double yearly production each following year.
      There is little doubt you will be in the red for first few years, but make money you get to 1000 tons {and later on, even more} year.
      Or within 5 years if at 1000 ton of rocket fuel made per year- your company will be worth more money than the total amount rocket fuel than company sold with the five years.
      But it would be easier, if can but cheaper lunar water and lunar electrical power- and that is possible.
      But if electrical was cheap as Earth’s prices, you could get cheap LOX from any lunar dirt {which per mass is 40% oxygen}.

  8. On the Moon, sunlight is about 8 X stronger. The solar panels would be on a metal tower. David Crisswell has written a lot about this.
    And once you have your power stations set up, you could build a highway of light.

    Here is one way of doing Mars. Build solar sails at L1. Send them to Mars with a 50 ton payload. When it reaches Mars orbit, it then releases the payload. The payload then lands on one of Mars moons. Once you have landed several payloads on one of Mars moons, you then send the settlers, and astronauts. They will then build the following.
    A power station on the north pole, and south pole, on one of Mars moons.
    Next, build a hypersonic tether. This tether would send, and receive payloads. The payloads that are sent out, are captured by the solar sail.
    When the sails are pushed by sunlight, they are solar sails. But when pushed by lasers, or masers, they then become lightsails.
    Over time, powerstations could be built in other parts of the solar system.

    When settling Mars, we need to think more than just Mars. But it’s two moons. We need to settle those.

    Now a question.
    Can an O’Neill space colony be built using large inflatables?
    It would be a large donut. And would house 1,500, to 3,000 people.
    It would also be built in sections, and would have an inner wall, and an outer wall. Between the two walls, would be dirt, and rocks. The dirt and rocks would come from one of the moons.
    I think Phoebus might be a good choice.

    1. “On the Moon, sunlight is about 8 X stronger. The solar panels would be on a metal tower. David Crisswell has written a lot about this.”

      In locations in lunar polar regions, one can have a site get sunlight more than 80% of the time.
      On Earth surface, one get useable sunlight about 25% of the time and in best locations on Earth {some parts of Australia, the Sahara desert region. and southwestern US, and other areas} the amount sunlight during the 25% of the time is about 1/2 the power of sunlight one gets on Moon, 80% of the time. BUT what important is NOT having 75% of the time without usable sunlight- which is what solar energy on Earth surface- and why it’s not a viable source of energy.
      And in addition you have several site in polar region in different location which get 80% of the time getting sunlight AND when some site no getting sunlight, other sites get sunlight, so one get sunlight nearly 100% of the time. Making the lunar polar region a useful place for solar energy for electrical power. But if you want to beam power to Earth, one collect solar energy in Geostationary orbit, any spot in Geostationary can get more 90% of time getting sunlight {1360 watts per square meter- same as lunar polar region} and you need to beam power a 1/10th of distance as compared to the Moon to Earth and in GEO the total energy one can collected, it get more electrical {by many factors} then Earth surface could use.
      So, what you do is make solar panels on the Moon for use on the Moon, and once make them on moon cheaply, one then ship solar panel from the lunar surface at 1/100th of cost of shipping them from Earth surface to Geostationary orbit.
      And GEO has infinitely more area to collect solar energy, as compared the lunar polar area which is pretty small area, or Oregon is a much larger area than lunar polar region. Also lunar polar region is a land shadows, so a 100 meter high tower would cast shadows for miles or have to design solar towers so they don’t shadow other solar towers. Of course could use entire lunar surface, but one only gets sunlight 50% of the time- which better than Earth. The lunar surface is also good place for nuclear energy.

      “Now a question.
      Can an O’Neill space colony be built using large inflatables?
      It would be a large donut. And would house 1,500, to 3,000 people.”
      Usually, an O’Neill space colony is bigger, but for a smaller number of people, it could better.
      But I would say there cost building O’Neill space colonies, sort like cost of building high rises. And though could grow food in high rises, the cost per square foot is high. So I would use Mars surface for growing crops. But O’Neill space colonies probably could more easily provide constant lightning and so one could grow more per year per square foot.
      I tend to think O’Neill space colonies could provide cheaper and better residential living areas, has compared to Earth surface. Though some or maybe most Earthlings may think that for their purposes, living on Earth is better. Or “better” is subjective and depends how you want to live your life.

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