Space-Based Solar Power

a public discussion sponsored by the Space Frontier Foundation

What Comes Next? Phase 1! Your Comments Needed!!!

Posted by Coyote on November 3, 2007

I’m back by popular demand…and you are back by even more popular demand!

It’s been almost a month since we published the Interim Assessment on the 10th of October in a very public event at the National Press Club in Washington. Then we took a little pause, did a few media interviews, and now we’re ready to get busy again!

You remain the central players in this effort. The Interim Assessment was built on the bedrock of comments provided right here on this website. Quite frankly, by working together in this wide open public forum, we learned more and spent less than any other study on record! More importantly (and to our amazement) we discovered enormous public enthusiasm for space-based solar power!

This enthusiasm even brought 13 national and international organizations together to form the Space Solar Alliance for Future Energy (SSAFE). Their goal is “to ensure that the benefits of renewable clean energy from space solar power are understood and supported by business, governments and the general public.”

So you see, our advocates are lining up. We need to give them something worth advocating for! Let’s make sure we avoid getting caught up in the enthusiasm and continue to provide sound, dispassionate, realistic, and feasible analysis!

Now we need to roll up our sleeves, sharpen our pencils (or click for fresh lead), put on our thinking caps, and get back work!

You’ve had time to read the Interim Assessment and think about it. What are your expectations for the next step? What should the Phase 1 Study look like?

You’ve probably also seen at least some of the the media coverage (for which we are grateful, because it expands our base of participants here!). What are your thoughts about it? What more can we do to expand awareness of our effort? Can we do more? Should we do more???

Let the brainstorming begin!


P.S. I have actually been promoted and transferred from Dream Works in the National Security Space Office to the University of Reading in the UK where I am pursuing a PhD in strategic studies under the hand of Professor Colin Gray. (Yes, I have a flat next to an Irish pub! Many locals have been briefed to full understanding of SBSP on bar napkins.) I’m very proud to remain a part of the NSSO’s space-based solar power team and am delighted to continue leading the discussions here, making public presentations, and giving interviews. It is extra work, but like Major General Armor said in the beginning, “Security in the form of clean energy independence is just too important to America, its allies, and the world!”

P.P.S. One news story called us the “Pentagon’s space hippies.” Groovy man!


44 Responses to “What Comes Next? Phase 1! Your Comments Needed!!!”

  1. Phil Mills said


    The British Interplanetary Society was really impressed with your presentation on Sat Nov 3rd at their HQ in London. Space Based Solar Power has now crossed the Atlantic!

    Today I talked with Rex Hall who we met at the symposium. Rex suggested that you make another presentation next year on SBSP and the progress made by then, at the BIS as part of a dedicated symposium with just you as the speaker.

    Phil Mills

  2. Dan Lantz said


    First, a small detail. Page 29 illustrations seem to show Terrestrial Solar Farm and SBSP Rectenna at approx same size, but perhaps it would be better to show sizes corresponding to equal total electricity delivered, to help demonstrate that rectenna is working 24/7, etc.
    More significantly, one thing that has happened with SBSP topic since Oct 10 is the ever more intense international “political” interest in the very problem(s) SBSP could solve, IF done on a sufficiently large scale. There could be more in the report that attempts to place the initial “crawl/walk” plan within a larger framework. The global concerns could be addressed with (perhaps somewhat vague) large scale plan that is reachable by smooth extension from starting plan. I would think that estimating some “tipping points” would give something specific to chew on, and provide opportunity for wide, long term support, based upon large scale being discussed. Such things as the estimated point(scale/time) where lunar resource use is “needed” should be more specific than “not yet”, and should be presented as a positive step! Let people know more of the specifics of how SBSP can be a real factor in global scale problem solutions, even if it may not happen this week, and they will rush to get it started!

  3. Coyote said

    Phil Mills: Thanks for the feedback! It was my pleasure to attend the British Interplanetary Society Event and to meet so many serious-minded space enthusiasts. Rex’s idea for a dedicated BIS space-based solar power symposium next year is certainly in the brainstorming phase at this point, but I say, YES! I think that would be a great idea. The more minds we can focus on the huge problem set that SBSP represents the better! Perhaps BIS would be interested in joining the Space Solar Alliance for Future Energy (SSAFE)?

    Dan Lantz: Good point about that illustration. It is somewhat misleading because it does not show the scaling of rectennas versus ground-bases solar power fields properly. However, that is entirely my fault, not our artist. He did a great job when you consider the sparse information we gave him and the fact that he did it for free! This illustrates the point (pardon the pun) that so many people realize the huge potential for SBSP to make such a fundamental improvement for humanity by providing another clean energy source and opening the highways to space that they are literally giving their time and talent to help this effort succeed! Your more significant point is brilliant and I couldn’t agree with you more! We need to do more to paint a clear vision, one that breaks out all the major contributing projects that build towards SBSP. I’d like to have everyone understand exactly what role they can play in making SBSP a reality. For that, they need to know roughly where we are going, and our step-by-step plan for getting there. I would love to have a science fiction writer help us with that! Perhaps a story can be told that will spark people’s imagination. Dan, thanks for your thoughtful comments. Please keep them coming!

  4. Edawg said

    Coyote said:

    I’d like to have everyone understand exactly what role they can play in making SBSP a reality. For that, they need to know roughly where we are going, and our step-by-step plan for getting there.

    Maybe there should be a meeting between small business and academia. There is a odd gap between engineers and business people. We just come from different worlds, yo!

  5. Edawg said

    To steal another thing from the sci-fi game “Halo” is the “United Nations Space Command.” Such a structure would be useful for planetary defense and keeping geo-politics stable with the ability to drop troop out of orbit (and darkstar like craft).

  6. Alienthe said

    Coyote said:

    We need to give them something worth advocating for! […] What more can we do to expand awareness of our effort? Can we do more? Should we do more???

    Since we are selling an idea it might be a good idea to give a physical demonstration that it works and is safe, all in a media friendly way. There are times when an initial goal post has to be quickly and successfully reached and I believe this is one of them.

    Allow me to propose:
    Use a phased array radar on the ground, preferably powered by a big solar panel, to track a van with a rectenna and make it power a few light bulbs or perhaps a sign so that it is clear to everyone and the media that the power comes entirely from the radar beam.

    Have some cows in the background to demonstrate just how safe it is but for goodness sake make sure they are healthy! One cow tipping over in front of the camera crew and the project is sunk.

    It combines the wow! with an objective demonstration how power is delivered across space and importantly that it can be done using todays technology. We can all agree here but if you get the media on board you will get a movement on an entirely different order of magnitude.

    PS: I hope it is not too off topic to congratulate you on your promotion (and seeing your collection of masters degrees I did wonder when you would start on the PhD).

    PPS: as for hippieness, this one is far too good to resist:

  7. Rodney said

    If we assume that building a Solar Power Satellite is analogous to constructing a dam–which isn’at a bad analogy. We are going to have a hard time persuading people that this can be done if we a still getting our concrete and rebar to the build site using porters. You’re going to have to roll up and your sleeves and think how you’re going to get a lot of stuff into orbit. If your intersted, I’ve got a paper quickly segueing to millions of tons per year to orbit with the right market incentive.

  8. Rob Mahan said

    I saw link to the recently released NSSO study in an e-newsletter from Aviation Week & Space Technology. After reading it and getting very excited about the potential of SBSP on a large scale, I decided to take some actions on my own.

    The first thing I did was contact someone high up in my own company (I work for a large U.S. aerospace contractor), bring the study to their attention and recommended that we take a lead role in getting SBSP under serious development. I received a very positive response and thanks for the timely and interesting information. (Another employee in a different division of our company is listed as one of the contributors to the study.)

    Wanting to do more, I have created a site on WordPress called Citizens for Space Based Solar Power (C-SBSP). My main goal is to enlist as many “average citizens” as possible in getting the word out by learning about SBSP and then writing to their representatives, industry leaders and media outlets. I want lots of people (aka voters) to get involved, take positive actions and ask the decision-makers to support the development of SBSP. I believe it is critical that the United States gets out in front and takes the lead, instead of playing catch up as we did in the early days of the space program.

    I am almost ready to start making the C-SBSP site known to as large an audience as possible … and to start writing additional posts and my own letters, too. Any and all comments and suggestions would be most appreciated. I hope my efforts will be viewed as a help, not a hinderance.

    Best regards,


  9. Coyote said

    Edawg: Your observation that businessmen and technologists need to come get together on this is correct! There is great cause for optimism. I am seeing more serious discussions between them in several different venues across the globe over SBSP than any other issue that I’ve dealt with in the past. This idea is catching on. Given the energy and environmental situation I think we are looking at the “perfect storm” to make SBSP a reality–starting small and growing to the 2050 vision that I posted earlier. Moreover, we are seeing genuine interest by politicians and lawyers who are seriously looking for ways they can help business “get ‘er done.” When it comes to the game “Halo,” I’ll have to take your word for it.

    Alienthe: YES! I agree that a very public series of proofs of concept, safety tests, and environmental impact assessments are needed–and we need to help the media to cover it fairly and without unduly exposing them to advocates or critics. I go back to General Armor’s first comment on this project, “…[T]his is just too important to America, its allies, and the world.” We’ve got to do this right. We want clean energy…not unsafe energy…or another energy source with massive environmental consequences. I think we’re in sync on this. You mentioned a cow tipping over. Have you ever gone cow tipping???

    Rodney: You are right…we need to massive cheap lift to orbit. I envision fleets of reusable rockets and spaceplaces. However, many propose space elevators, but they are about as complicated as doing space-based solar power in the first place–and may take as many spacelifts to build as SBSP. Others suggest slingatrons, massive guns, and other systems requiring enormous G-loads on launch. Still others suggest constructing SBSP systems on the Moon (which we will do as soon as the Moon is industrialized). I am interested in all of them, but am mostly interested in the logistics to make any suggestion a reality. The capability sells itself, and I want to field a wide variety of options. What I need most is thorough contemplation of the weaknesses and limitations of each suggestion. Sure! I’d love to see any papers on solving the launch problem that anyone has.

    Rob Mahan: Brilliant! If there were such a thing as the “SBSP Good Citizenship Award” I would give you one. I’ve looked over your website and think you are doing a wonderful thing! When the citizens are informed and have access to their political leaders good things happen! For our part, we will keep plugging away to learn more and pass along our growing knowledge in the public domain so the citizens stay informed.

  10. Alienthe said

    You mentioned a cow tipping over. Have you ever gone cow tipping???

    Cowtipping? Who, me? Oh not at all. Nonono, it was not me. And it was a long time ago and in a different country and besides the wench is dead, as they say… As an European this is an (unique?) part of the American culture I have not sampled.

    As for using phased array radars to demonstrate power transmission across space I’d say all the hardware is already established technology, though a minor software change might be required but nothing that would require much time or effort to achieve. Since such electronic beam steering would be needed as outlined in the report I’d say the companies in this business have a strong interest in getting aboard the project as soon as possible.

    One of my lecturers back in my student days told me of his time in the early space projects and about the can-do culture where parts were held together with “rubber bands and chewing gum” and it worked well. I hope SBSP can be the start of a new such era.

  11. Des Emery said

    Hey Coyote! — I knew you were a Hippie right from the beginning of this project ’cause only a Hippie would literally hitch his wagon to a star and fling himself into Space. And the British Interplanetary Society must recognize that, too. The Irish Pub will also be a good footbridge into new landscapes for you. Congratulations on everything!

    One hurdle to watch for is the tendency for any project like this to become too focussed on one troublesome problem to the neglect of the rest of entire program. May I suggest that at least two or three streams of effort should be considered at the same time. And then the project has you, advising the rectennae erectors, working to co-relate their work with that required by the solar antennae in space, and directing construction and operation of equipment systems, keeping the separate objectives working together.

  12. kumbu said


    I heartily support the idea of SBSP. I fear that we lack the political will in the west. Because its not profitable this quarter. All of you are doing a terrific job at NSSO and on this site. Congratulations on the NSSO report. Still, as a new arriver here, reading the report and this blog I feel like there is a bit of preaching to the choir going on. I do not get the sense of urgency that seems appropriate.

    Living in Asia its clear to me that the only way to avoid war between China and the west over energy resources is to expand the resource pie with extra-terrestrial resources. China can never have the car-person ration of the US. The planet could not sustain the carbon emissions, and we would need extra planets to support the oil consumption required, even if we could get around the carbon problems.

    I was stunned to see that the NSSO report stands firmly on an awareness that war between China and the west can only be avoided in the next 10-30 years, if we can find a way to supply cheap, carbon free, energy to all comers. Of course the report does not say it in the stark terms I have, but its there, to me, its clearly there. And the report even understands that if America is smart it will sell that energy to India and China. Wonderful depth of awareness behind the NSSO report. A reality sense I do not get by reading western media outlets.

    Who would have thought DOD had such vision lurking in its depths. Again. Congratulations!

    But, hello there. Are you aware of how little time we have before the war erupts? The Communist Party must maintain 10% annual economic growth to cling to power. It’s the only thing that will keep the workers out of the streets. More jobs. Nothing is more important to the Party. They do not care about the carbon impact that has. They will do anything to continue the current boom in China. Which is utterly dependent on China increasing its slice of total world oil imports, every year, as far as the eye can see. That way lies war. Americans may think that they have their belly’s’ stapled to the world’s buffet table… but guess what. China and India will do anything to obtain the energy they need to develop in the next few decades.

    Some posts on this site give the appearance that they do not yet understand the house is on fire. We need SPSB contributing 30% of global energy within no more than 20 years, and I don’t know if we even have that much time.

    May I remind you then. The house is on fire. Security for the US can only be maintained in the coming decades if we sell cheap, carbon free, energy to Asia. If we fail at this… well, travel to Dacca and spend a few weeks there….

    When the house is on fire its silly to have discussions about who is sleeping in what bed room, or exactly where the fire truck should be parked.

    Security for the US can only be had by investing in the future– not fighting over the past. But yet our entire political process is dominated by …. big oil.

    My apologies if any of this is rude. Again, Congratulations on the great report. But, whats next?

  13. I know this is not a political forum, but in this important political season, wouldn’t it make sense for someone to get Al Gore [Coyote inserts: or other influential political figures] up to speed about SBSP […]? […] [Al Gore] has won the Nobel Prize for his global environmental championing, and he has been active in real space programs (he brainstormed the Triana Earth Observing Satellite which still waits at Goddard Flight Center due to its being axed from the final Columbia mission […]. […] If government is required to “kick off” SBSP, he certainly would have the qualifications to announce it, would he not?

  14. Gary Oleson said

    Alienthe: Allow me to simplify your suggestion. There’s no need to use a van in your demo since all the early terrestrial rectennas are going to be fixed installations. Using a mobile rectenna adds unnecessary complexity and, worse, could give people the idea that we’re planning to power cars from space. Misconceptions about SBSP get started easily enough without help from us!

    I get a sinking feeling about our civilization every time I read a general-population discussion of SBSP or any other technical issue. 95% of the time I want to scream “RTFA” followed by “Do the math!”

  15. Andy Evans said


    I’m happy to see you made it across the pond. I returned from Colorado via California, and opened some dialog along the way concerning space logistics and space-based solar power. I am of the firm opinion that space tugs will lead the way in this effort, and I’m working to make that happen.

    Logistics infrastructure on Earth is assumed, competed, or manufactured, because it’s relatively cheap and easy to do. In space, to date, we’ve carried everything on each mission’s back like a rucksack, operated to failure, and called it a day or returned as empty as possible. Sustained efforts, like the International Space Station, Space-Based Solar Power, the Vision for Space Exploration, etc., cannot carry it all, cannot assume reliability will cover a multi-generation assembly, cannot operate without appreciable investment in support systems. Commercial communications satellites operating in life cycles around the 17 year range, start to experience problems with fuel, computers, system failures. Debris from thousands of launches litters Earth’s orbits at virtually every level. Failure to plan and invest becomes a commercial opportunity because reward overtakes risk, and demand is established by an oversubscription to wishful thinking. Space is not an easy environment, and transportation, servicing, salvage, provisioning, supply, and corrective maintenance are terms finally entering peoples thoughts as they think about putting bigger systems out there. There’s a lot of markets for space tugs there already, and there are more on the way.

    Space-Based Solar Power will require lots of logistics, and planners, policy makers, and designers need to understand the environments, plan the capabilities of their support system, and express those needs and capability gaps so that options can be analyzed or pursued.

    Think back in history, when Captain Cook island hopped across the Pacific and around the world, mapping and taking notes as he went. No trade routes existed except to known islands near each Continent. No one had any idea who was friendly, what islands were populated, or where way stations could exist. Cook’s scouting provided mitigation of risk, and an ability to segment risk that commercial shippers could accept. His work drove ship-building, shipping centers, and trans-oceanic trade for 237 years and counting.

    A system of unmanned, agile, reusable, flexible tugs that stay in space and do what’s necessary at the point of origin, enroute, and at the point of use…that describes what is needed. “What’s necessary” is agility and flexibility to do power, guidance, navigation, transport, positioning, fueling, servicing, salvage, etc. These are features that can be added to capable tug systems.

  16. Edawg said

    Score! Since planetary defense is a global issue it would make a great springboard for international cooperation on SSP. As far as I know there is no official plan to deflect an incoming asteroid. Is planetary defense apart of the NSSO agenda? […] Having an official public plan will have a positive profound impact on how serious America is about space, SSP, and planetary security. […]

  17. Dan Lantz said

    Kumbu #12:

    You have the right perspective! This is a life-or-death question for our species if not the biosphere. Read Gerard K. O’Neill’s “The High Frontier” for basic plan, Google “Criswell LSP” for near-term plan. Those who are not ready to devote full energy to Space are living in denial!

  18. Neil Cox said

    I just added the following to the talk page of for the article Space solar power. Please make appropiate corrections:
    I agree, there has been less discussion of sunsynchonous than geosynchronous, but sunsynchronous = solar synchronous has several important advantages: 1 The satellite flies about half way to GEO altitude, so the transmitting antenna is smaller and/or the beam can be narrower, making slightly smaller scale practical, thus lower initial cost. 2 Two sun synchronous satellites can supply most of the countries of Earth, every peak demand period, when the wholesale price of electricity is highest. This is because the satellites orbit is approximately over the sunshine terminator 3 The antenna aiming is slightly less critical. 4 station keeping for the satellite is much less critical. 5 The rectennas can be smaller, and/or less energy falls outside the rectennas. 6 Rectennas optimised for sunsynchronous can serve other types of SSP reasonably well. 7 I think the brief shading of the solar panels near the equinox is illiminated, but the moon still causes a solar eclipse rarely and briefly, so the beam is available more than 99% of the time. The 96% in the article should be 99% unless it is allowing for repair shutdowns. 8 We don’t have to compete with communications satellites for a geosynchronous slot. The disadvantages: The expensive rectennas are only used a few hours per day, until there are other types of SSP. 2 A very large sunsychronous SSP will briefly increase the path loss of an average of one geosynchronous communications satellite each time it passes the Equator in it’s semi-polar orbit. I suggest a separate article for solar synchronous = sunsynchronous, but do not merge Solar Power Satellite and Space Solar Power as both are well written. Neil/ccpoodle

  19. Neil Cox said

    Sorry, I left out the second i in
    Hi Edawg: If we use lasers instead of microwaves, we can suppliment sunlight to make the space junk and nearby asteroids more visable to the telescopes which are presently charting these hazards. If we eventually build gigawatt laser arrays, these can possibly modify the orbits of asteroids which pass close to Earth, so they are more likely to miss Earth on subsequent passes. The heavy lift needed for SBSP will open other options for changing the orbit of asteroids which endanger Earth. My first choice would be to put a pair of human pilots in each asteroid. The pilots will have a vested interest in not colliding their home with anything including Earth. Neil

  20. Dan Lantz said

    Neil #18:
    seems to show Earth-Sun L1 well past lunar orbit, let alone geosync. Still has advantage of shading Earth (if kept in place), but would be very large transmitter.

  21. I know this isn’t an entertainment forum, but “Sunsats” and “Island One” are original tunes of mine on Free of charge and so forth. You folks are working so hard!

  22. Edawg said

    I like the idea of using lasers and Lidar to detect/deflect asteroids.I just think something should be done in the mean time with our Russian friends who happen to have the other half of the Nuclear arsenal for planetary defense.Space economics could benefit greatly with Russia being another leg of the commercial New Space Market.

  23. Dan Lantz said

    Neil #18:

    Oh, THAT sun-synchronous orbit!
    On a more general note, I don’t recall seeing plans in which SPS is used to redirect beam when that SPS is in shadow, or to move power to where it is needed. That is, add rectenna to SPS to make it relay also, using transmitter that is alredy there. Mix and match as needed, go into higher orbits as size of transmitter is driven up by load rather than forced by diffraction.

  24. Neil Cox said

    Hi Dan: I belive a lunar synchronous orbit is also possible at an altitude of something like 20,000 kilometers. That would permit your phased aray relay to never be blocked by the Earth = The moon would always be high in the sky. Earth would make one turn underneath per 23.5 (24.5?) hours, so one relay could serve many rectennas over a period of 4 weeks, if the relay satellite is in semipolar lunar synchronous orbit.
    I knew almost nothing about phased aray antennas until I read your posts on this forum. I am catching up gradually.
    Is the total energy falling on the rectenna near Atlanta, Georgia about half what was sent from the moon, with one redirect relay about 95% of the way from moon to Earth? I’m guessing half the energy is scattered in minor lobes. The relay phased aray should be how many square kilometers for 2 millimeters wave length = 150 gigahetz frequency. From 20,000 kilometers can it focus the beam onto a rectenna less than one square kilometer? Perhaps the relay satellite can use the same phased aray to send energy produced locally = at the relay satellite to the same or multiple rectennas? Has any one built a relay type phased aray more than 100,000 square meters = 1/10 square kilometer? Neil

  25. Alienthe said


    Alienthe: Allow me to simplify your suggestion. There’s no need to use a van in your demo since all the early terrestrial rectennas are going to be fixed installations. Using a mobile rectenna adds unnecessary complexity and, worse, could give people the idea that we’re planning to power cars from space. Misconceptions about SBSP get started easily enough without help from us!

    This forum is dominated by people with deep technical insight and as such we all understand it is not needed. The issue here is getting the population in general and the politicians in particular on board and then we need to go beyond technical demonstrations alone. We need to use the media. Just look at any newscast: there is hardly any static displays; something just has to move. Pictures are slowly panned or zoomed, NEVER just sitting there. And that is what we have to do too: use their language, not the technologists’ language.

    Also we need to address the inevitable question about fast moving satellites, stationary rectenna farms and the handover between them. A display with moving parts will in my humble opinion address all these aspects and be far more media friendly.

    As for people expecting microwave powered vehicles: why not? It will just take a little more money and a little more time.

    I get a sinking feeling about our civilization every time I read a general-population discussion of SBSP or any other technical issue. 95% of the time I want to scream “RTFA” followed by “Do the math!”

    I know the feeling. The Apollo project revitalised the US interest in technical subject at a time when law and business was what people aspired to. This could be a similar catalyst. It sure is needed unless the entire West will be specialised in consumers only.

  26. Alienthe said

    @Neil Cox #18:
    Sun syncronous the way you describe it has another very important advantage: if the satellite spins around its own axis so that it is always facing the sun and one edge faces the Earth, it means a transmitting unit (optical or microwaves) requires only limited articulation which in turn saves a lot of mechanical wear.

  27. Dan Lantz said

    Neil #24:

    Solar and lunar synchronous orbits very interesting! Will have to sleep on it!
    There are many better places to learn about phased array transmitting/receiving antennae than from me!
    I’m pretty sure, however, that one “trick” in phased array transmission is to capture or bounce the energy going into the minor lobes at the next element, and send most of that energy in the right direction. Looking at lobe diagrams shows that the more elements, the less goes out the sides. Also, you need complete coverage to send energy, or the side lobes leak at every diffraction edge that is formed at each “hole”. The sparse array curse.
    Also, you can send signal/energy from phased array to multiple rectennae, perhaps an unlimited number, at the same time. You just have to know how combined waves need to look, and send that. This is much easier if you are looking at pilot signals from the rectennae, telling you where they are and how much energy they want.
    “Assessment” rectenna design seems to be approx 7km in diameter. This may be where atmosphere twinkle starts to come into play and/or a result of the frequency, no matter how large the transmitter is. The higher the latitude, the more they have to increase into ellipse to capture from Moon or Geosync, but not if from orbits that go overhead. The large number of rectennae to be built is far and away the largest cost of the full (in the case of Lunar Solar Power) system (unless you try to launch everything from Earth’s surface!), so they need to be as small as possible.
    I really, really really like your idea of using higher frequency. May need “Assessment” 2.45 or 5.8 GHz for thru atmosphere, but use higher than that to transmit to redirects!!! No need to worry about atmosphere transparency if not going thru atmosphere! Make initial transmitters much smaller! Probably the same number of elements, but closer together and each element smaller. I presume at some point load will drive size of transmitter up anyway, but being able to start much smaller, esp. from Moon, is great advantage. Would have to send everything thru redirect, even if Moon high, but great way to start!
    Redirects collect with rectennae (and perhaps their own solar cells), which need not be phased array unless you are trying to see image as with radio telescope, but then send with same phased array transmitter which would be used no matter what the power source. Need not be the same frequency. Could be laser from Moon, optimal atmosphere transparency frequency to Earth.
    I think you may get 80-90% efficiency thru redirect, as “Assessment” sez each operation (receive, transmit) is good for at least 80%, goals higher.

  28. Here is what we must do:

    1. Inform the people, in terms they can immediately grasp of:
    a. The immensity of the “energy business” including the scale of investments made and planned.
    b. The immensity of the problem we are setting out to solve.
    c, The urgency facing us and the need to invest appropriate resources – – now!
    d. The financial resource of the U.S. and the world – – most people do not recognize our strengths
    e. The consequences of further inaction.

    2. Now, develop a reasonable and comprehensive plan for:
    a. Developing the space-faring infra-structure needed, perhaps close to that Mike Snead described in his annex to the NSSO report – – invite alternative solutions and timing.
    b. Accomplishing the near term demonstrations essential to reducing investment risks and
    getting the attention of the public – – all of the public. Using the present Space Shuttle and International Space Station – – do not waste these tremendous assets for a pittance of “savings”.

    3. Sketch, to the best of our limited ability, the overall SPS plan – – for the next 200 years, including using the new infrastructure to industriailze our Moon and Earth-crossing bodies.
    4. Publicize this draft plan and invite improvements to it, perhaps using this blog. Update it annually.
    5. i.e. ——- Communicate effectively!!!

  29. Brian Wang said

    An interesting concept for solar power appears to be on track for testing in Palau by 2012.

    In September, 2007 American entrepreneur Kevin Reed proposed at the 58th International Astronautical Congress in Hyderabad, India, that Palau’s uninhabited Helen Island would be an ideal spot for a small demonstration project, a 260-foot-diameter “rectifying antenna,” or rectenna, to take in 1 megawatt of power transmitted earthward by a satellite orbiting 300 miles above Earth.

    Reed said he expects his U.S.-Swiss-German consortium to begin manufacturing the necessary ultralight solar panels within two years, and to attract financial support from manufacturers wanting to show how their technology — launch vehicles, satellites, transmission technology — could make such a system work. He estimates project costs at $800 million and completion as early as 2012.

    Reducing the size of the rectannas with low orbit solar satellite. Reduce the size of the cost effective solar satellites. Have several small satellites in orbit so that relatively constant power could be provided to multiple smaller rectennas.

  30. Brian Wang said

    I have an article about the two low earth orbit solar power efforts. There is the Palau one and the Space Island Group effort.

  31. Mark said

    The following idea seems to make sense and I wanted to know your take. Solar collectors at 20 miles up would absorb 8 times the energy than down here. An array of solar collectors could be placed on top of a balloon system and the energy could be transmitted down. The close proximity to Earth collectors would decrease the amount of energy loss and you wouldn’t need such large collectors. The balloon system would be above all atmospheric conditions so the energy would be consistent and the location would be safe from any storms.
    The balloon system could be as follows:
    The primary feature would be the solid structure hydrogen cubes that would provide the buoyancy. They could be 10 meters wide, 10 meters long and 20 meters high. Based on what I’ve read, this would give each the lifting power of about 9,000 pounds. The outer casing would be made of a (very) non-porous solid material for the four sides and top. The bottom could be constructed from a Kevlar type material. Each cube would then have a flexible ability to have different levels of hydrogen. The bottom would act as a diaphragm. This would allow flexibility without worrying about mixing oxygen or other gasses in the cube. Each cube could have a small pump and device that would either liquefy hydrogen or store it at high pressures. In turn, each pump would be connected to a larger network of hydrogen pipes. Upon demand, hydrogen could be added or removed from each cube. In this way, the altitude and equilibrium of the whole structure could be automated and regulated. Each cube, covered by solar panels on top, would provide 100 square meters of solar energy collection.
    The structure would have a central unit. This could be supported by a double layer of 32 cubes (16 on top of 16). The cubes would support a livable command center underneath. Among the functions of the command center could be:
    1. To hold the mechanism that would transmit the energy back down to a collector.
    2. To hold a hydrogen fuel cell that could generate energy at nights.
    3. To hold water. The water could be a source of hydrogen and oxygen.
    4. A docking bay for smaller similar craft bringing up supplies.
    Each cube could be attached to the ones to its sides or a framework could be built to which each cube could be attached. Additional cubes and/or frameworks could be built on land and then floated up and attached in air. Theoretically, cubes could continuously be added making the structure quite huge. Practically speaking it could be limited to a goal of 1 square kilometer (or 1.24 by having the central area plus 4 more square circumferences of 16,28,,36 and 44 cubes). The structure could have retractable or folding solar panels that could extend on-demand. This could double (or more) the solar energy absorption. One possible way that it could be done is by having “mini-cubes” directly on top of the regular cubes on the outermost perimeter. When the structure is stationary, these could be extended horizontally on tracks. Each would have a hydrogen capacity to basically carry its own weight. These could be retracted when the structure would be in motion.
    The structures would have mobility:
    By attaching fans or jets on the sides, the structure could travel to a desired location. We could thus mass produce these and then send them to other countries and provide energy to their collectors (for a fee!!). The structures could also be used as a part of a defense system. They could either be used to strike incoming missiles with concentrated microwaves or from a payload of “patriot” type missiles. They could also be used as “floating aircraft carriers” that could carry payloads of bombs to inland targets.
    Or, the structures could be made with small “thrusters” connected to the framework under each cube. After a structure’s construction is completed, tremendous amounts of water could be brought up. Eventually, the solar energy of the structure could be used to convert the water to a liquid hydrogen/oxygen fuel for each thruster. Then, from 20 miles up, it would launch to a geocentric orbit.

  32. Andreas said

    Neil #18, Dan #20: Sun synchronous orbit is typically at 600-800 km altitude, and the “dawn/dusk” orbit will provide sunlight 100% of the time. I think it is the perfect orbit for SBSP, next to GEO, as it permits transmitters or receivers to be up to 50 times smaller.


  33. Andreas said

    Dan #27: I wonder what the rules are for phased arrays involving a three-dimensional, possibly irregular arrangement of transmitters. I think it is worth looking into, because a swarm approach (as suggested in the below referenced thread, my post has not shown up yet?) could drastically reduce the cost and complexity of SBSP, IMHO.


  34. Dan Lantz said

    Andreas #33:

    I had great hopes for such an idea, but they were dashed (in the 70’s, actually) by the “thinned” or “sparse array curse”.
    I’m afraid it was my mis-reading of the concept of “smart” array elements that lead me to imagine cooperating “smart” separate satellites.
    Phased array works by looking as if it is single, large mirror or lens, with only one diffraction edge to mess things up. Any other diffraction edge really causes problems.
    The bigger the array, the sharper it can send a beam, just as with lens, but can have no gaps.


    I propose three major steps in thinking about Space Solar Power:
    (1) You should collect Solar Power in orbit, rather than on the Earth.
    (2) You should build the Solar Collectors from (mostly) lunar/asteroidal materials (In Space Resource Use).
    (3) You should build the Solar Collectors on the Moon!
    My current excitment is around the notion of sending power from the Moon to relays with one wavelength (even lasers) and then down thru the atmosphere with the wavelengths mentioned in the “Assessment”.

  35. Dan Lantz said

    Mark #31:

    The larger goal of many of those interested in Space Solar Power is to find the “firstest with the mostest” way to jump start Space as per “The High Frontier”.
    I’m starting to think that the military bases’ small and near term need for power (that lead to the “Assessment”) should be considered a separate project “within” or “towards” the larger effort, rather than the start of it. Otherwise we either end up waiting too long to get started (from the military point of view) or start with a plan that will not scale up, and will not “sell” at all.
    It is not a given that Space Power will be the main starter. Mars mission support and Moon hotels will almost certainly beat Solar Power Satellite manufacturing efforts to the Moon.
    After getting started, it will become easier to do things in Space than on the Earth. We need to get started!

  36. Neil Cox said

    Hi Mark: As far as I know your plan is workable, Can we start building in 2008? Maybe only 4 time surface energy. We should not over sell our idea. The only change I suggest is the altitude is not critical, and more is better. If we can occasionally reach an altitude of 30 miles, then we can have the balloon array as much as 100 miles from directly overhead. I agree free flying is essential as weight of 30 miles of tie down cable will eat up nearly all the payload. We likely cannot put a large system in even in LEO = low earth orbit before 2020, but we can learn a lot of details in the meantime from your balloon supported SSP = space solar power. I suggest tethered to the balloon array to provide some electricity and provide part of the manuvering. Neil

  37. Neil Cox said

    Hi Andreas, welcome to spacesolarpower. The phased array antenna may work well as a redirect for SSP. Perhaps they can be installed on Mark’s balloon platform when energy is arriving from far out in space to concentrate the beam onto a comparitily tiny receiving array on a moving military vehicle. I understand the phased array system can be made to work at light and infrared frequencies, which may soon be better for SSP than microwaves in small and medium scale SSP.
    Possibly you posted on one of the dozen? other threads at http://www.spacesolar Where to post keeps me confused. Neil

  38. Rob Mahan said

    Coyote, I want to help figure out the answer to your question:

    What more can we do to expand awareness of our effort?

    The answers to your next questions “Can we do more?” and “Should we do more???” are, in my humble opinion, a resounding “YES” and “YES”. As I mentioned in Comment #8 above:

    I have created a site on WordPress called Citizens for Space Based Solar Power (C-SBSP). My main goal is to enlist as many “average citizens” as possible in getting the word out by learning about SBSP and then writing to their representatives, industry leaders and media outlets.

    Your reply to me in Comment #9 above was very kind, most appreciated and highly motivating. As a three month self-appointed advocate for space-based solar power, I have sent information and requests for support out to many folks and even appeared on a local Atlanta radio show where the entire hour was devoted to space-based solar power and energy independence. (There is a link to the archived show on my website.)

    To borrow a phrase from Newt Gingrich, space-based solar power must become part of the “national conversation”. None of the presidential candidates mention space-based solar in their ideas for our energy future. Even Bill Richardson, former Secretary of Energy who published his views on our energy future in “Leading by Example”, does not even mention the idea of space-based solar power. Do we need a nationally recognized spokesman (Neil Armstrong, Buzz Aldrin, John Glenn, John Young, Tom Hanks, Mark Harmon, George H. W. Bush, Colin Powell, Norman Schwarzkopf, Al Gore, Burt Rutan, Bill Gates, … ) to become the public “face” of space-based solar power? Do we need to hire a marketing or advertising firm to help get the word out on a national level? Do we need to hire a political consulting firm or a defense contractor consulting firm to help navigate the case for space-based solar power inside the beltway?

    I learned that for every complex problem, there is a technical solution, a financial solution and a political solution. If you don’t answer all three, you don’t have a complete solution. There appears to be a lot of focus on the technical solution for space-based solar power (which of the three, I often think is the easiest to solve), but I’m not hearing or finding a lot on the financial or political solutions.

    Help me help figure out “What comes next?” so we can get started on a complete solution for space-based solar power that will lead America to energy and fossil fuel independence and enhanced national security.

  39. Edawg said

    Currently Wallstreet and politics are interlinked because of all the depression scares.Our technology shares are doing quite well even with a weak dollar and gold nearing 900 an ounce.Wallstreet is alought easier to convince than politicans who only care about one thing ,votes.If the investor problem is solved state-side we can look forward to other nations calling for a new outer space treaty.

    I wounder if Duabi would invest in ssp?They certainly got enough cash but it dosnt solve our energy independence.Scare tactics are the bomb

  40. 3seagull said

    One of my problems with conservative talk radio hosts (and there are many) is their astounding, ignorant, and even forceful argument that global warming and all things environmentalist are a hoax and a threat to economic growth and freedom. In the same breath they demand energy independence! So no one bothers to tell them that global warming solutions, environmental protection, energy independence, and BIG TIME ECONOMIC GROWTH are all synonymous and addressed by SSP/space settlement? Is it too sci-fi for them? They are so busy resting on their “principles” that they cannot see beyond their eyesockets. If global warming is a lie then they call me personally a liar every freaking day!! Shouldn’t we file a class action suit or something??

  41. Neil Cox said

    Hi 3Seagull: Clearly Russ Limbaugh is in denial about carbon dioxide emisions. Some of the other conservative radio talk show hosts are in favor of clean envirornment, and reducing consumption of non-renewable resources.
    Many of the proposed liberal solutions are restrictive of freedom and ecconomic growth, besides offering little hope of reversing global warming.
    Let’s focus where most of us agree: Building SSP will advance space and many other technologies and create good paying jobs, without bad side effects other than massive federal spending. There is reasonable hope that SSP will free us from bondage to foreign oil, stimulate ecconomic growth, make our environment safer, all goals of sensible conservatives and liberals and centrists. Neil

  42. Alienthe said

    OK, more food for though: To win this project you need to win the hearts and minds of more than the technologists, you need to address the public, the politicians, the people with the funding and more. Just some ideas:

    – make the PDF report available as HTML: it makes it easier for journalists to cut and paste to create more publications, it is more searchable and more web visible. Open a press center folder here for all sorts of publication resources.

    – a lot of really good illustrations are in the report and elsewhere, why not make these available separately with an inserted link to this project? That provides even more visibility.

    – more logos, a .ico-file for the RSS (which is how I mostly follow this debate). Got any patches going for the project? Might want to avoid ending here:

    A lot of PR will be needed in addition to technology.

  43. Paul Young said

    Hi All,

    we may have a solution for getting from LEO to GEO. It would probably take a month but no on board fuel will be required. The EmDrive could also perform station keeping and orientation changes for both the PV array and the microwave antenna (should this be required). I have seen the generation 1 (G1) working and seen the results from 450 test runs. The practical results agree with the math, for those who have the level of math required(I don’t but have had it checked by someone who did), please check the theory paper on the site. Generation 2 (G2) is under test now.

    Best Wishes


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