Space-Based Solar Power

a public discussion sponsored by the Space Frontier Foundation

Ad Astra Special Report: Space-Based Solar Power

Posted by Coyote on April 9, 2008

Look at the attention you’re getting!

Our very good friends at the National Space Society recently published a special report of their acclaimed Ad Astra magazine covering Space-Based Solar Power! It goes into some technical details, but best of all it tells the story about how the Caballeros worked with the National Security Space Office to make the Space-Based Solar Power Study Group report become reality.  It was based on a lot of the work done right here, on this blog!

So for those of you who have been contributing to the discussions here, THIS IS A STORY ABOUT YOU and the good things you’ve been doing here. So, the next time your spouse or significant other complains that you are spending way too much time in the blogosphere…toss him or her a copy of this magazine and say, “I’ve been doing important work to solve the energy crisis!” You’ll be telling the truth!

Kudos to the National Space Society and their Ad Astra team–they are great people to work with and are doing a great job advancing humanities spacefaring prowess. You are a member, aren’t you?


21 Responses to “Ad Astra Special Report: Space-Based Solar Power”

  1. Neil Cox said

    The article covers a lot of detail and accurately in my opinion. At we don’t seem to have a concensis on how to do this. I suggest that we persue short term many of the ideas and suggestions, by funding perhaps 100 possibly support technologies, such as heavy lift rockets and balloons, high power narrow beam lasers, millimeter wave power transmitting, redirect antennas, micro factories on the moon teleoperated from Earth, CNT = carbon nano tube ribbon and rope etc.
    I was impressed with the sandwich concept which solves several problems that were bothering me. Details will produce success or failure, but we need to start the engineering and building of the space projects here on Earth’s surface in conditions as close as we can simulate at reasonable cost, or we will loose the momentum produced so far. Neil

  2. Edawg said

    ohh snap..thats awesome

  3. Robert said

    Thank you Caballeros and NSSO for the work you’ve taken on, and for allowing this public forum. From many tributaries comes the harnessable river.

  4. Edawg said


    The problem with funding start up technology is that your left with the chicken and the egg problem.You can develop heavy lift balloons for TSTO but what are you going to fly off the balloons?You can make robots to work on the moon but then you have make a factory for the robots…It hurts the brain.There needs to be cornerstone that other companies can build their products around otherwise you just have really expensive development cost and no one to market it too.

    Do you know where I can find info on the sandwich concept?

  5. Neil Cox said

    A corner stone is helpful, but in the absence of a workable cornerstone that will catch the enthusiam of both the public and the big money people, we are left with funding little pieces, which may hasten results when we find the magic cornerstone and the finalized design. Feasability requires that we demonstrate the individual concepts at at least 1% of the optimum size and power level required for a gigawatt SSP.
    The sandwich requires concentrators which send sunlight to photovoltaic panels on the backside of elements of the phased array antenna which must approximately face Earth. The only disadvantage I know of, is some of the concentrators will be positioned poorly over part of each year.
    Advantages are the photovoltaic cells produce the electricity about a meter from the kysitrons or laser diodes, which are the center of the sandwich. The energy output of the kysitron or laser diode only needs to travel about a meter to the phased array element or optics which produce the very narrow beam. Each sandwich is mostly independent of other sandwiches, so failure of one sandwich allows the rest to be reconfigured for continued delivery of the beam. Multiple beams of adjustable power and beam width are easier with this modular approach. Scale up is limited by the effective range of the concentrator beams: I’ll guess several gigawatts. I have not seen sandwich mentioned other than the Ad Astra article, so there may be other important details to sandwich. Neil

  6. Dan Lantz said

    Congratulations Caballeros!

    Have just finished print (complete) copy of Ad Astra. Excellent! Very good 50 year look-back. Last event listed is publication of Interim Assessment! Will (re)join, was L5 member in late 70’s.

    Edawg #4, Neil #1:
    Check out Ad Astra pg 56 review of “The Lunar Exploration Scrapbook” book authored by Robert Godwin. Low hanging fruit if looking for specific plans-“most of these never” YET “made it off the drawing board.” “It hurts the brain” is appropriate response to the myriad possible paths, to many possible goals!
    Some see ISRU as general goal for immediate development, trusting that pay-off will come from many directions, thus do not want to tie it to any specific plan that then may fail or be obsoleced by better solution.
    Others see specific goals that cannot “wait” for ISRU, but need it anyway.
    Need to combine these energies, as Robert sez, into a “harnessable” form.
    Past history of SSP is example of twists and turns to work thru. Glaser observed solar energy falling on Moon, and invented SPS to (I believe) solve lunar day-night and Earth to Moon launch cost problems. O’Neill invented (modern) ISRU, and saw Glaser’s SPS idea as perfect starting project for In Space manufacturing. Criswell saw O’Neill’s ISRU and realized that SPS launch cost FROM MOON was a problem, which, combined with advantages of collecting energy on Moon’s EXISTING SURFACE, led to Lunar Solar Power. That’s just my current understanding, by the way. Point is how ISRU is major factor, and how ideas coevolve.
    Reminds one of the difference “lunar orbital rendezvous technique”, described in “Scrapbook”, made in Apollo. Not placing the whole return ship on the Moon greatly lessened the initial size/expense of the Earth launch.
    LSP does the same sort of thing for SSP. Too bad Ad Astra only talks about SPS, other than the one clause on pg 28: “…,lunar versus orbital basing,…”.
    If everyone else already knew about LSP, it would not be nearly as important to spread the word!

  7. cfrjlr said

    FCC denies license for one watt pwoer beaming demo:

    Experimental Licensing Branch
    445 12th Street, S.W., Room
    Washington, D.C. 20554
    May 07,2008
    Attn: Robert S Gammenthaler
    Moon Society, Inc
    P.O. Box: PO Box 940825
    TX 75094
    Dear Robert S Gammenthaler,
    This refers to application, File No. 0219-EX-ST-2008, for an experimental authorization.
    You are advised that the Commission is unable to grant your application for the facilities requested. There
    are possible harmful interferences to mobile satellite space-to-earth licensees.
    Responses to this correspondence must contain the Reference number : 6379
    Experimental Licensing Branch

  8. Robert said

    Well, I am stumped. Space Studies Institute President Freeman J. Dyson’s signature appears on the “Global Warming Petition Project” ( It seems fair to say that the claims of the petition are inconsistent with SSI’s stated historical research goals and represents a view counter to that of SSI’s founder and first president, Gerard K. O’Neill. This eventuality comes to light as the NASA Inspector General confirms James E. Hansen’s observation that political appointees in NASA’s public affairs office “worked to control and distort public accounts of its researchers’ findings about climate change for at least two years” in a way that was “inconsistent with the law that established the space program 50 years ago.” I’ve noticed that SSI has become very quiet lately. At any rate, there will be a distinct change in Washington come January. The new government should receive the quintessential SbSP presentation from Col. Coyote’s group, and well-functioning pens should be broken out for reprioritizing the space program, requesting cheap launch-to-orbit technologies for getting people, tools, and electronics off the ground, and after all remaining appropriate testing, moving lunar-built sunsats into position and into the energy portfolio sooner rather than later. You can always play the ace of hearts (protection of the biosphere) along with the ace of spades (energy security) in this game and do okay for investors, petroleum and other traditional energy providers, future high-orbiting residents, and the rest of us who would just like to see something cool done while the doing’s good.

  9. Rob Mahan said

    I don’t know why no one has thought of this simple, five step solution to the looming fossil fuel depletion problem facing the world. It’s simple, sustainable and I’m going to share it with you right here, right now … for free.

    1. Gather up all plant and animal matter currently living on the earth and in the oceans.
    2. Bury it all between 7,500 and 15,000 feet underground, preferably beneath an ocean.
    3. Wait 300 to 400 million years.
    4. Drill down to it and pump it all back out of the ground.
    5. Repeat.

    Follow these five simple steps and we will have a never-ending series of 150 year supplies of cheap, abundant fossil fuel.

    (Implementing space-based solar power would actually be cheaper, quicker, environmentally friendlier and every bit as sustainable … if we do it before the current 150 year supply of now-not-so-cheap fossil fuel runs out.)

    You’ll love the photo I used with this idea posted on Citizens for Space Based Solar Power!

  10. Robert said

    I’ve been thinking about this one. With apologies and long time respect for Professor Dyson, I’m going to admit that I don’t know the first thing about climate change or its underlying physics. There will continue to be a flood of positioning before the public by scientists, non-scientists, and vested interests on the subject of climate change, and we peons have to wade through this stuff. If there is a need to reduce greenhouse gas contribution, SSP, it seems to me, is a wholesale way to do it, if given a 50+ year period in which to do it. The public is not going to buy it without a sense of urgency and factual selling points. (On the other hand, we bought the Iraq war.) Some have posited that SSP is simply sensible risk management, worthy of doing whether global warming (anthropogenic specifically) is a factor or not. Akhenaten’s 5/31/08 posting on the India SSP thread is cogent and well noted. In sales training 101, creating a sense of urgency is far superior alarming people. We don’t need to back into totalitarianism either.

  11. Rob Mahan said

    I wish I could preview or edit my own comments here … hopefully this link to Citizens for Space Based Solar Power will work better than the one I put in my previous post.

  12. Des Emery said

    The “physics” of climate change or global warming is strictly mechanical; if heat is added to a system in equilibrium, the system will change. The planet is bathed in a fairly constant flow of heat from the sun, but if the chemical (not physical) atmospheric envelope surrounding Earth is changed in composition, then the amount of heat received by the lithosphere and aquasphere below the atmosphere will also change in automatic response.

    Many chemicals either reflect or adsorb heat. Carbon dioxide in very small quantities reacts to external heat in a very large way. While it is true enough that CO2 is an essential part of the life cycle of both flora and fauna, an excess of the gas does not result in an increase of flora since flora also requires oxygen, the same oxygen which is tied up in the excess CO2 whose production rate co-incides with the Industrial Revolution, in which our present society so wholeheartedly participates.

    The petition against Kyoto is strictly political, not scientific, in nature, and wrong-headed.
    There is little enough time left to get Space Solar Power initiated before climate change and global warming with the attendant human upheaval make it moot. Anything that limits the production of CO2 (burning fossil fuels or biofuels) in the meanwhile is a good thing. Let us hope that Solar Power (essentially electricity) rescues us, and soon.

  13. Neil Cox said

    I’ve been following the human caused global warming debate for two decades. My guess is a bit of truth, but seriously exaggerated. Let’s stress other reasons for SSP, as there is at least a slight possibility that global warming will fade in importance, perhaps before the end of this year. In my opinion avoiding Arab oil is the big reason for SSP. Neil

  14. Rob Mahan said

    You may not all be aware that in January, 2008, the National Federation of High School Associations (NFHSA) announced Alternative Energy as the 2008-2009 national high school debate topic. It is “Resolved: The United States federal government should substantially increase alternative energy incentives in the United States.”

    This information was posted on Citizens for Space Based Solar Power in January and debate research seems to be generating quite a bit of traffic, as far as I can tell. A few days ago, Hsdebater posted a comment, citing a paper by Virgiliu Pop titled Security Implications of Non-Terrestrial Resource Exploitation which raises excellent points about the concern for potential weaponization of space power satellites and conversely, about their relative vulnerability to attack.

    I posted a reply, suggesting the Space Based Solar Power As an Opportunity for Strategic Security – Phase 0 Architecture Feasibility Study and this Space Solar Power website as excellent resources to use in seeking answers to this major challenge area to the development of space-based solar power.

    It is very encouraging to learn that many of our high school age citizens are taking an active interest in a clean energy future for the planet, and that they are including space-based solar power in their discussions and debates. This is certainly a positive step in making space-based solar power part of the national conversation.

  15. Robert said

    I’ve just read Marc Kaufman’s 7/9/08 article: “U.S. Finds It’s Getting Crowded Out There” in the Washington Post. It describes the United States’ rapidly decreasing lead in space. The space vision announced in 2004 now seems to be floundering. If the public needs imagery it can understand, why not go with Kubrick and Clarke’s visuals in the film “2001: A Space Odyssey”? The star child at the end can represent the promise of human settlement of cis-lunar space, as we pursue the energy, security, economic wealth, and future scientific/exploratory/manufacturing potential produced by the lunar-built solar power satellite. If our engineers in reality can work a design close to the flat black planar array similar to the monolith in the film, well then, there you go!

  16. HS Debater said

    Hi, in reference to what Rob Mahan said:

    My concern with Pop’s argument is where he says that we would have to protect these space resources. Arguably, we already take military action to protect our energy supplies in the middle east. It seems clear that the military would want to protect the system that would supply almost all of our energy in the future – SPS. This would require space weaponization, which could be extremely bad.

    Responses? It seems like a relatively compelling argument.

    I’ve found a few sources who claim that SPS would be hard to attack, particularly in GEO,but it would still be possible for a developed space agency like China.
    Also, I found one source who stated that low launch costs would avoid militarization altogether because then it would be cheap enough for us to just repair it or send up another satellite. I can’t really imagine seeing launch costs go quite that low, though, and the US doesn’t seem likely to pass up an opportunity for space weaponization

  17. Coyote said

    HS Debater. Thanks for taking the time to think seriously about this. You’ll be interested to know that our space-based solar power (SBSP) study group advocates the development of all forms of safe, clean, renewable energy. We want a mix of such energy sources and want to avoid putting all of our eggs in one basket. Space solar power will be one of several concurrent energy sources.

    We also advocate for the business sector to develop and operate SBSP systems, not government(s). We much prefer the satellites to be ‘owned’ by international stock holders and investors. Plus we’d like to see each satellite broadcast power into several nations. This way an attack on an SBSP satellite will be an attack on all owners and customers and their nations. This will serve as a deterrent against attacks, backed up by military force to suppress the threat to SBSP satellites.

    Another thing for you to think about: With SBSP satellites on orbit nations such as Iran and North Korea will not need nuclear power plants for their energy. Certainly safe, clean electrical power can be broadcast to them at a market price below all the R&D that goes into building their first-ever nuclear reactors.

    Here’s a comment which is always controversial; space is already weaponized. There already exists in space and on the Earth the types of systems that we use every day for routine civil, commerical, and military space operations that can also be used as weapons to negate satellites. Everything for ramming one satellite into another or merely jamming satellite signals is already in place…it merely depends on how you use the systems we currently have. We’ve already witnessed a number of episodes of hostile satellite jamming and bandwidth piracy around the globe. Fortunately, most space faring states are highly motivated to use space peacefully. But if war between space faring nations breaks out here on Earth I believe it is highly likely that those nations will negate each other’s satellites–the alternative to negating uninhabited satellites may be the killing of more people on Earth. This places advocates of “space sanctuary” in a strange moral dilemma. Unfortunately, achieving orbit does not place activities in space beyond the realm of human affairs. It is really a matter of politics as usual, no matter where your assets lie; air, land, sea, or space. Preventing battles in space depends on preventing wars on Earth.

    So, with this in mind, the way to protect space-based solar power satellites is to ensure that the outcome from attacking one of them is an unacceptable expansion of the war (militarily and/or legally) against the attacker. In other words, the consequence outweighs the benefit. Plus, if SBSP is part of a proper mix of safe, clean energy sources in use, the target value of such satellites drops.

    What do you think? I’m anxious to hear your thoughts.


  18. Robert said

    Don’t forget the anthropological and psychological aspects to a full-blown SSP program. The idea early on, visionary as it was, was to have those living in space to “own” the industry. That is how these folks would make their living, delivering power to the home planet and to space settlements and ships of exploration. SSP is the tremendous opportunity to build new societies, if you will, on the vertical plane. Defense applications go wherever humans go, but so does banking, farming, education, construction, entertainment, retail, garbage collection, etc. We don’t need floundering piecemeal solutions, where wildly different blind spots hinder engineers, entrepreneurs, investors, manufacturers, planners, politicians, psychologists, etc. This program needs a singular vision and a directed funnel of money. It should be announced, Apollo-like, by a President. Participating enterprises and nations can then get their ducks in a row, adhering, more or less, to the Glaser-O’Neill plan. Tell the candidates to “drill up”!

  19. Edawg said

    As technology advances so does the damage a lone nut can do.97% of people will pry have an invested interest in not harming their own power supply.But as the decades go on the odds of an attack on a SSP array shift from earth based attacks to attacks from space.And that’s if space colonization happens.The first step for an international SSP project would pry be a Global Launch Alliance.It would be easier to get payloads to ?? angle of launch to orbit.But thats if we have the Aries V booster.Small TSTO will pry push the launch rates in to the millions if used for construction purposes.Having all the ducks in a row will be a good start otherwise people will be accidentally shot in the face VP style.

  20. Tom Harris said

    Freeman Dyson also signed the open letter to the UN Secretary General opposing the UN’s stance on “stopping climate change”. Here is the letter, with which I and many others working on this issue agree:

    Tom Harris
    ED – ICSC

  21. If I had a greenback for every time I came here… Amazing writing!

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