Space-Based Solar Power

a public discussion sponsored by the Space Frontier Foundation

An Invitation:

Posted by Coyote on July 24, 2007

Our very good friends at the Marshall Institute are graciously hosting a “Washington Roundtable” discussion here in Washington D.C. on 8 August to discuss space-based solar power.  It is open to the public.  Jeff Kueter, the president of the institute, asked me to post this inviation to all of you.  If you can make it, please attend … and do follow the RSVP instructuctions to be courteous to our hosts!

The details follow:


Energy from Space:

Examining the Potential of Space
to Provide Energy for Earth


Where & When

The Capitol Hill Club
300 First Street SE
Washington, D.C.

August 8, 2007
Noon – 2:00 p.m.

Lunch Provided Reservations Required

Please RSVP by calling
(202) 296-9655 or email

 As the nation considers calls for energy independence, might answer
lie in the heavens? Capturing solar energy in space and transmitting
it to Earth presents intriguing possibilities for those concerned
about energy supplies, environmental policy, national security and the
continued development of space commerce. But, is it possible to cost-
effectively harness power from space?

Dr. Martin Hoffert of New York University and John C. Mankins of
Managed Energy Technologies LLC will review the current state of the
technologies and outline steps needed to determine the feasibility of
utilizing space to provide energy on Earth.

About the Speakers

Dr. Martin Hoffert – Professor Emeritus of Physics and former Chair of
the Department of Applied Science at New York University, Dr. Hoffert
is a leading authority on advanced energy technologies. Prof. Hoffert
has published broadly in fluid mechanics, plasma physics, atmospheric
science, oceanography, planetary atmospheres, environmental science,
solar and wind energy conversion and space solar power.

John C. Mankins – During a 25-year career at the Jet Propulsion
Laboratory and NASA Headquarters, John Mankins was the lead for NASA’s
1995-2001 Space Solar Power research, as well as serving as the
manager of the Exploration Systems Research and Technology Program.
Since leaving the space agency, he has become a successful technology
management consultant, and continues to pursue advanced renewable
energy technology as co-founder and Chief Operating Officer of Managed
Energy Technologies LLC, and President of the Space Power Association.

George C. Marshall Institute
The George C. Marshall Institute, a non-profit research group founded
in 1984, is dedicated to fostering and preserving the integrity of
science in the policy process.  The Institute conducts technical
assessments of scientific developments with a major impact on public
policy and communicates the results of its analyses to the press,
Congress and the public (

The George C. Marshall Institute
1625 K St. NW Suite, 1050
Washington, DC 20006


51 Responses to “An Invitation:”

  1. Archie Leitch said

    It’s about time. My senior thesis in college (+30 years ago) was based on solar energy capability – in Michigan’s upper peninsula of all places. Hope this dialogue finally lights a fire under this concept. The possibilities are endless.

  2. abecker said

    This site is great. I was trying to build an online presence devoted to SSP at but have had other things filling my time recently. My goal was to promote the concept and bring together a community of stakeholders. I’d be happy to share ideas with you guys. I really think these ideas need to be promoted more in the clean energy community and less in the Washington beltway & space industry circles. Clean energy is exactly where I am coming from.

  3. Coyote said


    I agree…it is long overdue. We have a tendency to wait until a pending crisis forces our hand. I submit for your consideration that the current environmental awareness and recognition of pending energy shortages makes a “perfect storm” for us to seriously consider space-based solar power long and hard.

    Glad to have you here. Look around and please contribute early and often!

  4. Coyote said


    I like your site! Please share with us any of your thoughts on space-based solar power! This is a hard and long-term project that demands that we think our way forward in total cooperation.

    I have to say that the success of this site is due entirely to the good works of the Space Frontier Foundation–who has been interested in space-based solar power for years.

  5. Dan Lantz said
    for an existing solar power satellite (needs some parts still)

  6. speedyphoton said

    As I see space based solar power for use here on earth, it will happen but not within the next 100-500 years. Very few if any of us alive today will see it’s large scale use. There are so many technical challenges that solving them will be very expensive and therefore must be spread out over many decades. I dare say that there will need to be several breakthroughs that are not even dreamed of today to make this project feasible. One thing that may speed the process up would be the space elevator if they are successful in overcoming the obstacles standing in it’s way. What kind of transmitter will be used to broadcast the many terawatts of power back to earth and will it be blocked by weather? When will the superconductors to deliver this power once it is collected here on earth, be developed? What about constant maintenance?
    Eventually what will the cost per kilowatt hour be? So many problems and no stable political system to stay behind it. Also with our continued move toward total Socialism in this country will we even be able to afford to do it. If not maybe someone else will, but then will we be allowed to partake of it. It may someday become reality but for now it is a dream, like finding another intelligent life in our universe.

  7. Coyote said


    Believe it or not, I shared your view when I was offered this project a few months back. I actually had the opportunity to pass on this…or to simply kill it and move on to an easier project with a short time horizon and a very bright chance for success. But I recognized that clean energy independence is one of the most critical strategic issues for America, or allies, and the world, so I gave it a second chance. I am now cautiously optimistic. I can see a path forward that makes this happen inside of the next 50 years, but we must avoid blunders.

    If you would, please, checkout a discussion that I started a while back titled Crawl, Walk, Run… ( I am advocating a very unorthodox and indirect approach to this problem. The fact that you and I are discussing this on the internet for everyone to see is proof of the unorthodoxy…the fact that I do not want to build a large government program signals the indirect method. See what you think, and please comment.

    Now, Speedyphoton, I ask you specifically to comment widely on this site and into the future. I need critics and cynics who can help keep the limitations that reality imposes in front of us at all times. This will be a long, hard, trek.


  8. Patrick the Geek said

    Only in the United States would one be asked to design a multi-billion dollar solar power station to produce millions of dollars of power. There are enough acres of otherwise unusable or unused land here to collect enough solar energy to serve all of our needs, with plenty left over.

    How many residential rooftops are also available for solar collectors? How many solar plants can be built for the cost of one $250 million dollar Space Shuttle launch? Stepping over dollars to pick up pennies will not solve out energy requirements;
    intelligent use of resources will.

  9. SRA said

    Back in the late 1980’s, my consulting firm Space Research Associates, was contracted by the Space Studies Institute to prepare a study on the use of lunar-derived materials for the construction of a Solar Power Satellite. It seems that SSI has looked at many aspects and approaches to the SPS concept, have you been in contact with them?

  10. clockmaker einstein said

    Yeah. This is an awful, horrible idea. Any time you make a ‘power source’ it is going to be used as a weapon. Space should be weapon-free by law and custom. Considering the US DOD is in charge of this project, I have zero confidence in the ability of such a project to ‘uplift mankind’. I am simply judging this based on history and a view of US government actions in the international arena.

  11. Eric Hawthorne said

    What I don’t get is why bother with space-based solar?

    1. There is plenty of sunny land available in the middle of most continent, not to mention every rooftop.
    Why not exhaust terrestrial potential before going orbital?

    2. The greater concentration of solar energy in space would be made up for by microwave
    transmission losses, no? Has anyone done the math on this?

    3. If the satellites are outside of Earth’s silhouette from the Sun’s perspective, then more energy (therefore heat) is being added to Earth (that would have bypassed Earth otherwise), which will tend to increase global warming, albeit a small factor I suppose.

    In summary, I’d need to see a system diagram showing the orders of magnitude of various energy amounts,
    conversion inefficiencies, costs etc
    and these in comparison to terrestrial solar pv.

  12. techresmgt said

    This is completely and utterly amazing. In 1985, I worked feverishly to find a way to convert solar energy into electricity and to find a way to beam solar energy to Earth receiving stations. After 911, I realized that the ideas in my head were doing no one any good, so decided to send the entire project, registed mail, to President Bush, The White House, in 2002. You may read the chronology and true story here:
    After not seeing any major Administration moves toward this solution, I did my best to contact every person with influence that I could to affect change; Robert Redford, Cal Thomas, to name a few; the list is quite long. At the beginning of this year, February 26, 2007, it finally dawned on me to try and contact The Honorable Al Gore to achieve some movement on this project. This time, I photocopied all the documents I had sent to the White House, found Al Gore’s address in Tennessee, and mailed them to him. His office did receive them and acknowledged my efforts, although they got my name wrong on the acknowledgement letter. I am only an amateur scientist, no Ph.D. after my name, difficult to get someone or anyone with any influence to read my profound and innovative ideas. Looks like my persistence has finally paid off. Space based solar energy beamed to Earth recieving stations is feasible and quite efficient. When orbiting satellite collecting stations are properly configured and designed, they will be able to “throttle” the amount of solar energy to collecting stations on Earth. The stations can be anywhere on the planet, geosynchronized orbits will not be necessary. As I said before, these ideas were sent registered mail in 2002. (I have the White House acceptance stamp on the reciept in my office) The letter I sent to the White House alerted them to the fact that energy independence is a National Security issue. Seems they were fully unaware of this fact in 2002, or at least, ignoring the fact. Think for a moment how much better a world we would be living in if there were not so much dependence on fossil fuels throughout the world. Here we are in 2007 and that is what everyone seems to be fighting about as the awareness of the strategic limitations of said fuels is in dire straits. To say these kind of ideas are not suitable for civilian energy use is wrong, in my opinion. […] It was designed for peaceful purposes and thus, use for all people, all over the world. The word “can’t” is not in my vocabulary and for those that desire a more peaceful world for our children, it should not be in their vocabulary either. Steven G. Alexander; E=mc3

  13. Mike Stern said


    the intensity of the solar power is reduced by distance^2. For that reason, “just” take solar dishes into the vincinity of the sun and send the reflected burst of sunlight back to earth.

    Of course, I have no idea what materials could be used for that, but that probably only depends on serious research.

  14. Philip Robey said

    Hi, I just found this site by way of msnbc. I am sure this isn’t where to place ideas, but I’ll place my idea here anyway. First, you could make use of micro satellites (by this i mean really small – like a quarter or smaller in size). These would be launched into space by a system I saw in popular science where they launch a satellite via a long enclosed path on the ground which is supposedly going to be great for light satellites. I believe with future development these quarter or smaller size satellites could be made almost as light as air and you would just pack these into a mini satellite launch vehicle to a designated orbit just for these satellites, was dispersed into space they would actually have enough processing power on board to use reflected light to position themselves where needed to be and then they could reflect light onto another popular science idea i read about which is a windmill in the sky that would be connected to the ground with tethers but instead of generating electricity they would just hold up water or molten metal chambers to be heated from the reflected light from the micro satellites. If anyone would like to call me about this idea just e-mail me for my number. Sometimes it takes me awhile to respond to e-mails.

  15. Matt Everett said

    In the age of space travel where we are falling back to the designs of the 60’s and 70’s for getting payloads into space I highly doubt a space based solar array will be cost effective.

    It doesn’t really matter how cheap you can make it or how big because the bigger it is the more it costs to get into space and the level of cost to maintain it will be painful. So the idea of putting a massive solar array into space is just not even remotely as practical as building renewable energy sources here on earth. At least not until the cost of getting into and maintaining object in space goes down.

    Now, there could be a use for a solar based array in space that actually powers space based objects, but to get past gravity with all that weight and the modular design needed to support such a large multistage project. Look how well it’s not working for the ISS. Mir’s entire lifetime cost was 3% of the current ISS costs from what I’ve read. So, as a US project you can bet it will be insanely expensive once the government gets involved. If the government doesn’t get involved then it will be more privatized energy with higher than normal maintenance costs.

    All together even if it was practical to launch that much mass into space and not have it destroyed by orbital debris I can’t see how it could be more cost effective than the investment of land based solar, wind and other renewable energy.

    Wind is really the best I think, though complete data on how earths winds might change is mostly guesswork. In the wake of climate change we should think about making a power structure more immune to disaster. Wind, hydro and ocean wave generators seems like the most reliable but solar is also a decent choice.

    How about for starters we push everyone to CFL and then to LED light bulbs and start reducing energy usage and enforcing efficiency instead of dreaming way to produce unlimited power.

    Energy is a lot like food, the more you have sitting around for convenient and cheap use the more people will use. The fact that it’s becoming more expensive in most ways is a good thing since most energy usage also contributes to pollution. So, by and far the best plan is to enforce energy efficiency on individuals AND corporations. It can work and it can start working tomorrow and in reality people don’t even need legislation to start helping, but most of them do need education.

    Nuclear power seems to be working out great for France and they aren’t exactly the technological mecca of the world. Yet their lack of reliance on foreign oil is clear in their lack of desire to invade Iraq, smarter than us on that one as I think we can all see at this point. Storage is a problem, but it’s hardly a problem of such unimaginable potential that it cannot be solved. Pebble Bed reactors seems to hold a lot of potential for making transport and storage of nuclear waste a lot easier. Many of the best places to store nuclear waste have simply not been thoroughly investigated. As a potential source of nuclear weapon fuel the security concerns have thwarted a lot of innovation but I think that is mostly undue as few nations are really pursuing nuclear weapons. We can’t let Iran’s choice to pursue nuclear weapons change our energy policy nor let energy companies scare us into thinking that the nuclear power plants we’ve been running for decades are not realistic source of energy.

    Think about it like this, if we had more nuclear energy we’d have less need for oil. If we had less need for oil, we’d have less terrorists. I also think we will need to back off environmental concerns to keep costs reasonable during our effort to reduce oil usage. Just because you can’t see Global Warming doesn’t mean it’s not a much larger threat than a nuclear reactor breach. Just like our energy our pollution needs to be diversified also and especially in the form of producing less CO2.

    Even the most green technologies pollute at some level and saying we will eventually meet renewable standards simply isn’t good enough. We know we can provide the countries electric needs via nuclear power, it is a solution that could vastly lower energy costs and open the doors for electric cars. One thing electric isn’t and that’s efficient, but it is convenient and as a fuel is clean. A common electric device cost the consumer more and part of not polluting is not using fossil fuels but that also means more burden on our overall electric needs. In other words, preventing Global Warming means using more electricity because all the light bulbs in the world cannot offset the power being generated and wasted in global automobile output. So, realistically reducing CO2 means not just green energy needs, but simply MORE electricity all around. From my understanding building enough renewable energy plants will take up a lot of space and time since they tend to put out low amount of power and more or less take up large amounts of space, so most green power has low energy density (like hydrogen), solar, wind. Hydro is the one that can really put out, but it’s also the least green of renewable energy.

    How is nuclear not the answer ?

  16. Matt Everett said

    Plus how could you ever shift you energy policy to a space based object that you could hardly defend. Any significant amount of power (if you could actually generate anything major) would be just a giant floating liability.

  17. :Jonathan Kohn said

    Dear Community,Dear Community,
    It is common sense that in this time of troubles partly caused by our ever hungrier need for power, this topic should be on CNN to ask: “Why has this not been a goal of the US?” We plan to devote our vast economic and scientific know how be subdued by what other greater cause? This topic has been around for some time and websites such as are an incredible source of knowledge on the subject. I believe as a community of a large enough size a network news channel would pick up the story. That is the real challenge, educating the masses. It is great for those of us who understand the elegance of what is being proposed that we have this website. However if as a community we do not get this to the masses, it will be for not. Please reply to this if you are interested in bringing this to the public through mass media.

    Jonathan Kohn

  18. Hi, Speedyphoton, Good questions!! We over at SSPI see that most of the hard problems have already been solved. Just need a WELL FUNDED (Congressionally chartered) company to put it all together, like Comsat was.
    Wireless Power Transmission would be used to broadcast the 5 GW standard power beams back to earth. Depending on the rectenna owners’ choice of frequency, (ISM band – 2.45 to 5.8 Gz) weather should be no problem – perhaps 5% would blocked by heavy rain. See
    for example.
    Maintenance and construction would be telerobotic. 2nd gen Superconductors on earth – standard T&D grid is fine. But check out 2nd generation superconductors we plan tor use in space at
    We don’t need space elevators to start construction – just reusable rockets to make several thousand flights a year. (Atlanta and Chicago each do a million flights per year each NOW – similar size vehicles). Companies like SpaceX and others are pursuing this now, although it will require a huge MARKET in order for them to build these. But Hey that market is ready to go if SBSP is started at the same time!!!
    The Rainbow Rider

  19. elteemike said

    I looked for the name of the late Dr. Gerard K. O’Neill, but did not find any mention of him or his work. He has written extensively on this subject, as far back as 1977 in his book “High Frontier”. As an interested non-scientist/layman, I thought he had some exciting ideas. His body of work may be worth another look.

    Unfortunately, unless there’s some way for a cartel of some kind to form and charge the rest of us all the market will bear (ie: use it as just another instrument of control), I doubt we’ll ever see anything like this. Too bad…what an exciting prospect for the future and energy freedom.

  20. berkanatechgroup said

    I believe space based solar power is a fixation. Considering how much it costs to send anything into space, why not just use the money that would otherwise be wasted sending and building a space based solar array to build a larger solar array down on earth?

    30 square miles of the barren uninhabited deserts in the American southwest could supply all the electricity needs of the entire US using the conventional 15% efficiency photovoltaics; imagine what could be done now that the world record for photovoltaic efficiency is over 42%! ( ) I assure you, if solar power is to be cost effective, the cost of sending a solar collection array into space could be better spent making more and larger solar collection arrays down here on earth. And the cost of transmitting the power from space can’t possibly be more cost effective than transmitting the power via wires down here on earth. In fact, if we are going to have that much money ear marked for sending solar arrays into space, by using that money to build solar farms here on earth, we could probably have enough money to build a storage system and extra capacity such that the excess solar power collected during the day could be used at night, or perhaps even storing enough during the sumer to use when winter solar power generation falls short of energy demands.

    Why must there be a fixation on sending things to space, as if anything in space makes it better? We’re hardly even utilizing terrestrial solar power to its full advantage. Before we look to spend hundreds of millions of dollars sending solar collectors into space, let us first take advantage of the huge tracts of barren sun-drenched land that we have here on earth.

  21. berkanatechgroup said

    By the way, the statistics I cited in my previous post are based on research done in Hermann Scheer’s excellent treatise on solar power based energy independence, A Solar Manifesto. I highly recommend this book; the research that went into it is excellent, and the reasoning is illuminating.

    As for my comment about 30 square miles of the American South West being enough to provide all the electricity we need even using 15% efficiency PV panels, let me elaborate my own point of view on this: I don’t think we should have one giant solar farm in the American south west. I think the entire sun belt should have distributed solar power generation in many solar plants wherever there are barren areas baked by the sun. I think laws should be passed that mandate that every warehouse and apartment building with a flat roof in the Sun Belt (Which stretches from California through Alabama) either install solar panels of their own, or lend the space to have public-utility owned and managed solar panels installed in exchange for use of the electricty. Every house in the Sun Belt should be required to use solar water heaters, using gas or electricity only to supplement the remaining heat needed to heat the water up all the way. (Israel has just such a law, and it saves them huge amounts of energy.)

    I assure you, the plan I outlined above would be far less expensive to implement than a space based solar collector, and would be far less risky. And if all that is done and we still don’t have enough power, then by all means, consider going to space, but until then, any serious discussion of a space based solar power system is really rather foolish.

    Please, I urge all of you to read the works of Hermann Scheer. His books “Solar Economy”, “Energy Autonomy”, and “A Solar Manifesto” have policy recommendations and much of the research pertaining to an efficient and effective solar-power based economy already worked out. Read these first before devoting your time to pursuing a space based solar power system.

  22. Manuel Garcia said

    A bit late in spotting this site but from what you all have achieved to date it is quite impressive.

    The amount of interest from all walks of life, not just true believers,will ensure that there will be a structured environment in which to discuss and promote this fascinating and important subject.

    Ilook forward to contributing what I can to your discussions and I wish you all the best for your future endeavours.

    The newbie

  23. jwiley said


    Thank you for your consideration of the general public for this concept.. Your forum was linked in Slashdot:

    A concept I have studied for over three years is applicable here, and I would like to attend this forum to see how well it may fit.

    There are two pieces to my concept. First, the APL has funded a program for over 10 years called the High Altitude Tethered Balloon program for a number of Near-Space applications including persistent surveillance and secure long-distance high-speed communications by use of a demonstrated fiber-optic tether.

    Secondly, a field pioneered only within the last couple of years has demonstrated the ability to move power through fiber-optics, “photonic power”. This immature field may provide an important medium in the space-based solar power argument – namely that a satellite’s laser or microwave transmission could be captured by a balloon -above nearly all weather effects and about 95% of the atmosphere- and retransmit that signal to the ground without much further interference.

    There exist several different configuration possibilities as well: that the balloon itself may be the satellite harnessing the power, that at some point on the balloon’s tether a transmitter be placed to beam power to remote locations, and that such a balloon has a variety of other military applications. Please note Lt. Col Edward Tomme’s Appendix C “Near-Space Support to USAF CONOPS” here:

    Also, Dr. Geoff Landis is an expert in this field, will he be attending?

    Thank you for your time,
    Jeremy Wiley

  24. Coyote said

    Wow! The blog has been busy over night! I guess that’s the mirical of national media attention.

    Hi, all. Let me provide some responses to your comments (thank you, by the way):

    Patrick the Geek: You’ll be glad to know that government is not going to do this…commercial industry is…whenever the business case closes. Our job here is not to build it, but to identify the critical technology pathway and to stimulate investment in those areas and to develop our spacefaring infrastructure incidental to other programs already underway that also make space-based solar power more viable.

    clockmaker einstein: I understand your concerns and agree with you. Fortunately, we are talking about a very benign technology. By using large antennas for power beaming from orbit to the Earth we render the broadcast safe. You can actually stand in the broadcast beam. Also, keep in mind that this is NOT a DOD program. The DoD wants to be a customer of some commercial company that will operate space-based solar power systems and sell power to the DoD. The National Security Space Office is working closely with the Department of Commerce Office of Space Commercialization to move this effort into the commercial sector as soon a possible. We are also developing this concept in the public domain, hence this discussion. If the intent were to develop a weapon the DoD certainly wouldn’t let me do so in an open Internet website talking to you! Whatever we discuss in this open forum becomes part of the common heritage of all mankind…sounds sort of like all those space treaties we signed, doesn’t it?

    Eric Hawthorne: Why bother with space-based solar power when we can to ground-based? Excellent question. Read the discussion on this website titled “Space Solar Power: Much More Than Clean Energy.” Basically, space-based solar power gives me 24/7/365 constant state power that is immune to night/day/weather cycles. Moreover, I can broadcast the power from space-based systems where I need it, when I need it. I can’t do that as easily with other systems, and certainly not as quickly.

    techresmgt: Sorry, dude…your paper hasn’t come across my desk. There have been a number of studies on this over the years. John Mankins, the former NASA leader of this field is working closely with us.

    Philip Robey: I am very leery of reflecting white sunlight back into the atmosphere to run windmills due to the increased warming affect.

    Matt Everett: I am totally on board with developing all of the various sources of clean energy you mentioned, although I find it ironic that nuclear energy is now considered “clean” by many of its former critics. The bottom line is that we cannot afford to put all of our eggs in one basket when it comes to energy. Nor can we be wasteful of dollars in building our energy infrastructure. That’s why government will be looking to the commerical sector to step out on space-based solar power as a business proposition when the time is right. There is no doubt that the business case cannot be made right now, but the time is coming…

    :Jonathan Kohn: Yes! Whatever media attention we can gain is most appreciated. We need to get this idea into the public domain where it can park imagination and debate!

    elteemike: I was reminded of the good Dr O’Neill’s work this past weekend at the Space Frontier Foundation’s NewSpace conference.

    berkanatechgroup: I think the assertion that a mere 30 square miles of desert can be converted into a ground-based solar farm that can power the entire U.S. is overstated, even at maximum efficiencies. Also, remember that we are taking an indirect approach. We’re not going to step off by creating a large government program. We’re going to monitor and promote the development of related technologies over time and as the business case closes for providing power from space we will seek to stimulate commercial development.


  25. Eric Dujardin said

    Why put the solar panels as far as in space ? They could just rest in the upper atmosphere, near the surface of the air sea at the bottom of which we stand. Put a few robust He or H reservoirs around the panels to keep them floating, a 20km cable down to the ground, and there you have panels immune to the shade of clouds.

  26. First – congratulations on the planned meeting; unfortunately I won’t be able to come. Good luck!

    Second – in response to berkanatechgroup above – 30 sq miles of Arizona is far from enough. It’s a very simple calculation: incoming solar power is about 1 kW/m^2 or 1 GW/km^2, so 30 sq miles or 77 sq km with 100% efficiency gives you at most 77 GW. “All the electricity needs of the entire US” amounts to about 462 GW (electric). At 15% efficiency, 77 GW becomes less than 12 GW, so you’re off by a factor of about 40.

    But that’s only *peak* power. Average power would be 1/4 of that at best (actually there’s a cosine factor for latitude as well). So we actually need a factor of 160 more area – about 5000 sq mi.

    And that’s just for US electric use – to cover all US energy needs would be 5-10 times as much, and the whole world would be another factor of 4 – 100-200,000 sq mi.

  27. Philip Robey said

    I see the point of not wanting white light to be directly sent into the atmosphere. I don’t know if it would make much of a difference as to whether the idea is good or not, but I didn’t want to power the turbines in the sky with reflected sunlight. I wanted turbines in the sky (which are supposed to be miles up in the sky) to keep aloft chambers of water or something that could be heated and that energy would be used to power a generator on the ground.

  28. Earlier studies have shown that the postulated vast costs of building a large-scale SPS for the global grid could be reduced by up to 95% if the raw materials for construction were derived from ET materials. Since SPS offers non polluting sustainable energy with independence from unpredicatble or hostile regimes here on Earth ,and since there is already a plan ( Plan Bush) to return astronauts to the Moon-now is the time to make the case for the “Vision” unimpeachable, by linking the Moon clearly to SPS. There is,in short, a clear economic as well as scientific ,case for exploration and development of the Moon and asteroids. construction, to set beside the ecological and strategic case for SPS. If the USA does not do this,India,and or China most likely will, It is time to revisit Gerard O’Neill’s “High Frontier”

  29. Dan Lantz said

    cf-28-Michael Marten-Smith
    Yer gitten WARM

  30. live2scan said

    (Short bio) non-aerospace or solar power engineer, but advanced space propulsion and solar power systems were sort of the family business, (Dad worked for NASA at Lewis lab till the mid 70’s) and I started a chapter of the old L-5 society. I’m familiar with the concept, but the present situation is very different from the Gerrard O’Neil days.
    Let’s look at some of the assumptions concerning the SSPS show-stoppers.
    1.PV cells are high cost per unit- you have at least a half dozen companies working flat out to produce PV thin film cells at a cost per watt on par with grid power or less(Daystar, Solopower, Nanosolar, CGIS; Boeing and many others, SI; and a few others using polymers. Several of these folks are right on the verge of mass production of PV @ gigawatt per year outputs and that’s just to start. Clone that output per factory line prn.
    2.Launch costs per pound are way too high for anything so massive as an SSPS to be built from ground launched components-
    look at JP Aerospace’s site. Remember, a GEO sited SSPS already has all the rotational velocity it needs when it leaves the Dark Sky Station, it just has to move from the top of the atmosphere. Slow is OK. To all you old time SF buffs, remember the Silkies and Levels of Logic, Don’t get hung up on the need for wings and massive flaming boosters. In fact if you were to build JPA’s ion powered vehicle to run on Daystar’s mylar cells IT WOULD BE AN SSPS!!! No futher development needed.
    The Ascender could carry a triangular shaped section of the system to the station as its power source (at least partial).
    The He needed for lifting the Ascender could be extracted to support the Dark Sky Station and the nacent SSPS allowing the rest of the Ascender to parachute back to Earth for a refill.
    When completed the SSPS would travel to GEO using a combination of bouyancy and ion/arcjet/resistojet power, you pick. Its probable that for this system, since it is essentialy on a one way trip,that most of the He that was initially used for bouyancy could be canibalized for reaction mass (arc or resistojet); ie: nothing much is wasted.
    Succeeding Ascenders/SSPS’s could be powered by the output from the initial SSPS. With so much concentrated wattage
    you might be able to use a hot air/cheap gas instead of He for lift in addition to providing energy for thrust.
    An initial version could be built rather cheaply and then scaled up prn. The only components that would need to be full size to start would be the Ascender and DSS and those would be useful tools in their own right for many other applications.
    3. These are high-tech systems that need alot of development-
    The Ascender is a BALLOON.With CGIS power, it is a mylar balloon.You have those at your kids birthday parties. Microwave power transmission nukes your popcorn.
    I think if something like this was actually implemented that it would not take very long for you to realize that beamed power for Earth based reasons is the skin of the apple compared to what else would flow from this kind of system.
    A PRACTICAL, CHEAP,DEEP-SPACE TRANSPORTATION SYSTEM, MAYBE. Allowing man commercial level access to space, finally.
    I think I hear Homer Simpson somewhere. DOOOGH!

  31. SystemsRanger said

    What about a space tether? Electricity is generated simply by moving a copper wire through a magnetic field. Drop a line from a satellite as it moves through the earth’s magnetic field and beam that energy back to earth. No details here, just an idea. I think this may have been tested once and it generated much much more energy than was expected.

  32. Coyote and friends,

    Indeed, SSI commissioned the excellent study by SRA. Their conclusion was that the Moon was the preferred source of material to construct the most cost effective power satellites, if the design were optimized for construction from lunar resources.

    The front page of the SSI website,, has an excellent summary article by Prof. G.K. O’Neill about the potential and pitfalls of SSP. Anyone who worries about turning these systems into weapons should understand that they are much better targets than weapons, for fundamental physical reasons.It is just not possible to focus the beam sufficiently to produce physical destruction on the Earth.

    SSI has the only complete set of final reports from the Federal government’s Satellite Solar Power Study of a quarter century ago. You may find some of the information useful. NASA has to request information from us because they do not have a copy.

  33. Coyote said

    Michael Martin-Smith, Dan Lantz, and Lee Valentine (Hi, Lee…it was good to meet you at SFF!)

    I am a huge fan of the “Build ’em on the Moon” concept, but it will take me a long, long time to build the infrastructure on the Moon to duplicate our start-to-finish fabrication processes that we enjoy here on Earth.

    Don’t misunderstand me, I believe that eventually we will be building SBSP satellites (and lots of other things) on the Moon. But we need to start locally…to test the concepts…to field some capabilties…and eventually to trasition to lunar production. We’ve got to get it started here…and convince people when the time is right to move to the Moon.

    But I like this…because it is the right extension of this concept into the future. We need vision beyond our noses. Kudos.

  34. Gary Oleson said

    I think that space based power will start out as an export industry for the US. Industrial electricity prices in the US were only about $0.061 per kWh in 2006. In Japan, they were about $0.121 per kWh in 2005. In Italy, they were about $0.174! The ability to drop power into most areas of the world will allow us to follow the highest prices, at least doubling (and probably tripling) our early revenues and making the whole project much more feasible.

    Countries where the price of electricity is at least 150% of the US price include India, most of Central America, and about a dozen countries in Europe. That doesn’t include China and most of Africa, where we don’t have data. Selling power will help both our balance of payments and our foreign policy.


  35. Coyote said


    Brilliant strategy. That advances the business case.

  36. live2scan said

    I think that space based power will start out as an export industry for the US. Industrial electricity prices in the US were only about $0.061 per kWh in 2006. In Japan, they were about $0.121 per kWh in 2005. In Italy, they were about $0.174! The ability to drop power into most areas of the world will allow us to follow the highest prices, at least doubling (and probably tripling) our early revenues and making the whole project much more feasible.

    Countries where the price of electricity is at least 150% of the US price include India, most of Central America, and about a dozen countries in Europe. That doesn’t include China and most of Africa, where we don’t have data. Selling power will help both our balance of payments and our foreign policy.

    The problem that I see with exporting grid power from an SSPS is that a lot of the technologies that will help make powersats possible (thin film PV cells, esp.) will decrease the need for developing a centralized power grid in areas that lack one today. The communications industry is a good example with WIMAX and cell phones allowing the rural 3rd world & U.S. to skip past copper & fiber cables. Targeting heavy industry as potential customers(rectenna right over a major factory or industrial park sort of like a Direct TV with a bit higher signal)might make better economic sense.

  37. Dan Lantz said

    re 33 Coyote
    Thanks for response!
    Main point Criswell makes is that the Moon IS the BEST POSSIBLE SPS! It already exists, for starters.

  38. Coyote said

    Live2scan: You and Gary must be conspirin’. That, too, helps the business case…and I like that!

    Dan Lantz: Keep your vision. It will happen. We must be patient and follow the business case.

  39. clockmaker einstein said


    I don’t expect you to give up your career for some pie in the sky pacifism. But at least be honest. Once you have energy-beaming infrastructure in space, it is a very small step for some military person to say ‘ok, lets make a copy this satellite and focus the beam’. You are in similar shoes to the scientists of the 20s and 30s when they could see what was coming around the corner. . . at the very least start up some ‘bulletin of the space scientists’ and try to steer the politicians so that they don’t wipe us all out in 50 years. . . . maybe you can get them to delay armageddon for 100 years.

  40. live2scan said

    I have to take issue with Clockmaker. The chance that some bozo, whether in the military or somebody with a political or religious axe to grind, will try to fry a shopping mall with a power beam is, of course, non-zero. That logic implies that we shouldn’t produce fertilizer (Oklahoma City Federal Building) or 737’s loaded with jet fuel (911). We should be imaginative and take precautions, but I think the risk from nuclear is far greater and the risk from foreign oil dependence is greater, still.

  41. cfrjlr said

    Chuck Divine has published a blog summary of the meeting.

  42. Joe Russo said


    All of the writings have me thinking with a pasion as I have four pages of thoughts, facts, and suggestions to ponder on a little more before writing. I would also like to ready Chuck Divine’s blog first. In the mean time, I hope Dr. Geoff Landis was present. I am sure he has a lot to say and I believe he might have many answers to the other questions on demos.

    Coyote, thank you for pointing out that Oleson has a strong argument. He supports something others and I has pointed out to the group months ago and I believe his figures are with confirming the values for your report; a very strong argument and popular subject worth building on.

  43. Joe Russo said


    You ask why not exhaust terrestrial potential before going orbital?

    I think we might want to argue that we need to develop alternatives to help conserve the resources we still have. Is that not a more win-win and non-confrontational approach?

  44. hey there,

    really nice post. Solar power becomes more and more popular these days, hopefully new solutions will appear to solve existing energy problems.

    Keep it up!

  45. neil said

    Quote: There are so many technical challenges that solving them will be very expensive and therefore must be spread out over many decades. I dare say that there will need to be several breakthroughs that are not even dreamed of today to make this project feasible. ~True to fully implement SSP = space solar power~ One thing that may speed the process up would be the space elevator if they are successful in overcoming the obstacles standing in it’s way. ~We could assume the space elevator will be available on launch date. If not, we will have to scale back, which is typically easier than scaling up on short notice. Alternately we could just pay the much higher launch cost. Likely SSP is worth the extra money even if it never supplies more than two percent of the world’s energy needs~ What kind of transmitter will be used to broadcast the many terawatts of power back to earth and will it be blocked by weather? ~Some wavelengths deliver more than 1/2 the energy though very thick cloud cover. Magnetrons or klysitrons are the usual choice. I’m hoping millons of laser diodes can be phase locked into a very tight beam. This will allow larger existing solar sites to receive the energy~ When will the superconductors to deliver this power once it is collected here on earth, be developed? ~Maybe never, but I hope we are doing what can be done to advance superconductor technology. SSP can succeed without super conductors~ What about constant maintenance? ~Perhaps robots can be developed to repair the equipment in space. Robotics is still advancing rapidly~
    Eventually what will the cost per kilowatt hour be? ~ Maybe one dollar per kilowatt-hour (including development costs) but that may be the the typical peak demand cost of electricity by 2050. The big plus of SSP is it supplies power near sunset, which Earth surface solar does not. Earth solar also is puny in December at high lattitudes. looks encouraging. Neil~

  46. Philip Robey said

    Hi, I commented awhile ago about micro mirrors. Well since then I have changed the idea in light of new information. What if for focusing the sunlight you still used micro mirrors that could allign themselves, but they would focus onto a compressed gas container (possibly) in space. The reason for compressed gas is that in time the gas could be collected in space so it the stuff being heated wouldn’t need to be transported into space. the reason for the micro mirrors still, is that you could use the earth’s magnetosphere to move the mirrors from a low orbit to higher orbits. Thank you for your time.

  47. Coyote said

    Philip Robey — Fascinating! I’ve heard some similar concepts from the solar dynamic advocates. It certainly merits further investigation.

  48. Edawg said

    That is really cool,it is almost as cool when I seen an Xb-70 when I was a kid.I had no idea what it was at the time till I saw it on discovery wings several weeks later.An then there was that article in aviation weekly

    Im not insane im just misunderstood =)

  49. Philip said

    I just want to say that the new information I was reffering to was the magnetosphere information. I found an article in a magazine that said NASA or some group was planning on launching mini probes that would power themselves with the magnetosphere to Mars, and I thought it would also work for transporting mirrors for the power system. I’m not sure what other ideas are out there for space based solar. I don’t spend a lot of time looking up the idea, because I spend most of my time focusing on improving simple things. Personally, I feel space solar power is a good idea, but not for another 30 or 40 years. Anything that could allow it to come sooner would be great though, because eventually we will need a lot of energy that we won’t be able to get from earth because of the side affects. Thanks for your time.

  50. Solar said

    Yes! Keeping in mind the drastic environmental changes and rising fuel prices going Solar is one option open to all at minimal investments. The Solar Water heating systems are so easy to install and most of them come in a Do-it Yourself kit, With the technological advancement the once heavy, bulky hard to move panels are now available widely in light weight easy to carry by one personal only packages. The advancement in technology is not only limited to light weight, but for those concern about the aesthetics of the panels, the good news is that the panels are now available with a variety of trim colors to choose from and can be easily matched to your roof. Saving about $25.oo on ones electricity bill every month on a residence of 4. We all use hot water, as one of our basic needs and what can be a better way, than helping our environment, saving our resources and ourself’s some money other than by investing in a Solar Water Heating System.
    There are a couple useful websites I’m aware off, that I would like to share with you
    1. – is a comprehensive source of information on state, local
    , utility ans federal incentives that promote renewable engery ans energy efficieny.
    2. – one of the many manufacturers of certified Solar Water Heating Systems available. One place I saw the light weight panels and trim color options I was mentioning earlier.
    Lastly, the local utilites in some areas also provide additional rebates and incentives for adding a Solar Water Heating Sytem to your exisitng water tank.
    Keep the look out on. Feel Good and save- money for you, environment for us.

  51. Philip said

    Hi, I have posted some ideas on this site, and my latest one is a very radical, possibly revolutionary way of generating solar energy on earth or in space. I am wondering if someone in this forum could email me to critique it. The engineering for it on a large scale probably wouldn’t come about for 30 years, but it would allow for the capture of a ton of energy (like dyson ring type volumes).

    Thank you for your time.
    E mail is

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