Space-Based Solar Power

a public discussion sponsored by the Space Frontier Foundation

Time to Build! A First Look at “The Initial Plan”

Posted by Coyote on October 13, 2008

All,

Its time to let actions speak louder than words. We’re going to build the first ever space-based solar power satellites!

I made this announcement at the International Space Development Conference and again at the New$pace (properly spelled with a dollar sign) conference in Washington D.C. this summer. Now it’s time to let you in on what has been discussed. We are still at the beginning of this project. That’s why I want to start by going public. I believe in providing transparency into this project because developing another source of safe, clean energy is just too important to the US, our Allies, and the World.

In addition, I want to hear from you. You probably have lots of ideas that can help us out. Now, let’s look into our project a bit closer.

Background:

Earlier this summer Ambassador Roger Harrison, the Director of the Eisenhower Center for Space and Defense Studies at the United States Air Force Academy, had the idea of building a small SBSP demonstration satellite at the Academy and in concert with a handful of other highly technical and competent universities inside the US. He invited me to serve as the “Visiting Associate Director for Special Space Solar Power Projects” at the Eisenhower Center. Yes, that ominous sounding title is a mouthful that makes me chuckle every time he says it. For some reason it makes me want to wear a bigger hat with my uniform.

Our Vision, Mission, and Mandate:

Our vision is to light a single bulb from space and in-so-doing light the path for business to follow.

Our mission is to give academy and university students a one-of-a-kind educational experience solving real world energy problems on the path to commercial development of space-based solar power. At the same time, this will help build the work force for industry to capitalize on.

Our mandate is to Keep It Cheap And Simple and deliver it Soon (KICASS). Be careful who you pronounce the acronym in front of…and please use a hard ‘c’ sound, because a soft ‘c’ is unacceptable!

Project Overview:

The project involves the building of two satellite systems concurrently, one “heavy” and one “light.” This dual approach using radically different methods gives us greater assurance that we will succeed in the event that technical, legal, financial, or other challenges bog down one effort. Both satellite missions will be launched into space, if possible. The desired launch dates are in 2010.

Each satellite must weigh 400 pounds or less and be prepared to ride into orbit for free on an ESPA ring. In order to keep the weight of the satellite down, we must use lasers for power beaming because the microwave systems are way too large. There is a benefit in this. Neither the Federal Communications Commission nor the International Telegraphic Union need to be consulted for laser energy beaming as there are no associated frequencies that must be deconflicted. Such consultation would be required if we were using microwave.

The “heavy” satellite mission represents a more complicated set of tasks and greater expense than its counterpart. It will place on orbit a satellite that will collect power and broadcast it to Earth via laser (1.0 or 0.86 microns). In order to keep the size of the solar array light and manageable, we will accept several orbits to allow the satellite to store energy and build up a sufficient charge for broadcast to the ground receiving station where the lightbulb will be illuminated. The use of a positive control laser at the ground receiving station will be used to allow the satellite to aim its laser precisely at the receiver and to authorize its discharge.

The “light” satellite mission turns the experiment on its head. It will place on orbit a satellite that merely contains a receiver and the lightbulb that will be illuminated by a ground-based laser (1.0 or 0.86 microns). Visual observation of the light on the satellite being illuminated during the laser broadcast will indicate success.

To keep the project as cheap as possible, the use of existing ground equipment is desired. Using simple satellite designs and employing proven hardware is also desired.

The satellites need not have a long on-orbit life and our goal is to allow them to safely deorbit at any time after successfully completing the experiment, which will likely include the requirement for replication by independent observers.

Limitations:

International Traffic in Ams Regulations (ITAR), which I hate with a passion, prevents us from working with non-US universities and non-US citizens.  (I personally cheer on all attempts to improve ITAR (WIHWAP) so we can collaborate more broadly with our traditional and especially our non-traditional international partners.)

Money is a factor. We have to do this on the cheap. Ambassador Harrison is exploring ways that organizations and individuals can make tax deductible contributions to educational institutions which can be used to fund this project. In addition, I am sure he’ll accept funding from government organizations that would like to advance this concept.

Some will accuse us of trying to field a weapon. This is simply not the case, but we are taking measures to alleviate such concerns. Theresa Hitchens from the Center for Defense Information sits on this project’s advisory board. She has complete access to everything we will be doing. We share her belief that providing transparency into this project is the principle method of preventing baseless accusations.

Conclusion:

There you go. Now, once again, you know as much about this project as I do…and I’m leading it!

Please provide comments and lets get the discussion going.

Cheers!

Coyote

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63 Responses to “Time to Build! A First Look at “The Initial Plan””

  1. Jay Dugger said

    What wonderful news! I hope to soon learn where and to whom I will make donations.

  2. I have asked this question numerous times.
    What is the advantage of gathering Solar Power off planet?
    Are there extra free electrons in Space?
    Is there something RE collection/transmission that makes the Space based gathering of Solar Power efficient?
    If you have answers to these questions, I have the vehicle.
    Let me know, OK?
    Steve Smyth
    SmythSpace

  3. scot4space said

    Even though ITAR restricts international involvement in construction, If the orbital track and time of either satellite is available it may be an opportunity to get the international community involved in observing it, from professional and amateur astronomers,to school children and members of the public. In the case of the “light” you could have a competition for the best image if technically fesible.
    In the case of the “heavy” have you looked at using the laser not only to transmit energy but information on the satellites’ health as well, maybe NASA would be prepared to contribute as part of a space communications demonstration ?

    scot4space

  4. Coyote said

    Jay Dugger: Dude, I shall keep all of us informed.

    Coyote

  5. David C said

    Hope it is an LED bulb not an energy waster.

  6. This should be like the Olympic flame, put it somewhere prominent like the top of a lighthouse or a skyscraper, and never let it go out. That would be some good marketing for you!

  7. Dr. Feng Hsu said

    Hi, Coyote:

    Haven’t heard form you for a long time as I am told that you left for UK right after the SBSP press relase last October and is now working on your Ph.D. somewhere in London, correct? It’s great to hear the good news about building a twin SPS sats. However, I am wondering if you have discussed or cordinated your effort with Paul Damphosse? As you may aware that we are also planning (with the support of DoD and NASA) on a SBSP demo project borad the SS/ISS, and a number of workshops have been held so far with a finanlzed SBSP demo project plan been sent out to NASA for project approval most recently…..

    Please keep us informed of what we can do to support this great technological endavor for the long term well being of mankind!

    Best wishes,

    Dr. Feng Hsu
    Sr. Aerospace Engineer
    Head, Integrated Risk Management
    NASA GSFC, OSMA
    301-286-3416
    Feng.Hsu@NASA.GOV

  8. Neil Cox said

    Hi Steve Smythe: Short term advantages are advancing science and technology and stimulating public interest. In 40 years we may have run out of good locations to put wind turbines and harvest solar energy, and be building more costly alternatives. Near Earth, in space, has thousands of times more total energy to harvest for a rapidly growing human ecconomy which is moving into our solar system. SSP related technology will help us colonize the inner solar system. Please give us some details on your vehicle, such as how soon can it lift 200 tons, if we give you a billion dollars in seed money? We may not have any years to spare. Human civilization may collapse back to hunter-gatherer, unless we do something spectacularly useful soon. Neil

  9. Coyote,
    I have followed SSP development closely and believe it is a great potential benefit to our society and the world. Best of wishes really! With this specific project, consider contacting SpaceDev in Poway CA. They have already developed a generic small sat bus called MMB-100 which is low cost/off the shelf. They are experts in low cost micro/nano satellites and may offer technical expertise for a degree of recognition. Also, they make large deployable structures with high expansion ratios, a potential huge benefit for deploying large solar arrays. Mike Sirangelo is the CEO and the website is http://www.spacedev.com

  10. Robert said

    Can Doug Sharp, Joe Nasal, and our team at General Physics be of assistance? In various active consulting capacities, we have developed close working relationships with NASA, DOE, DOD, Fortune 1000 businesses, governments, utilities, research institutions, energy transmission and distribution companies, and others. We are at http://www.gpworldwide.com. In reaching for the shortest elevator speech I can think of, we help get ducks from many ponds to line up, train in the classroom and online, integrate talent, processes, & technologies, promote performance improvement, and keep costs trim. We look for sensible “incubator” opportunities. I’d like to think that all of humankind has a large and permanent benefit in store from SBSP and related activity, and an interesting 40-year old story to tell.

  11. Hi Neil,
    I don’t need a bazillion, or whatever that number was you mentioned.
    Why 200 tons?
    Your response is the first time in about fifty tries that anyone has had anything at all to offer.
    I agree with your assessment…but don’t think it justifies the expense right now…this can be put into service within a year, or so once the Gaia Two concept is introduced as Earth’s First Personal Spacecraft…

    http://smythspace.blogspot.com/2007/01/smythspace.html

    Imagine an array of six…tails together, oriented for maximum exposure, visible from Earth…like a huge daisy…powering our future…when the time comes, it’ll happen…if it’s better than gathering right here at home.
    Thanks for the offer.
    I’ll take $50,000 for 20% of the future action right now.
    Between that, and the website’s potential, I can generate the rest.
    20% of all SmythSpace related action forever…act now!
    Ya wanna see spectacular?
    I got spectacular whenever anyone’s ready.

  12. Robert said

    Oh. The forgoing comment is called “hi visual, big chunker”, having just learned that in training in Troy, MI. Guess things are still in the “hi visual, small chunker” range, in which case I’ll chip in a few bucks, if you let me know where.

  13. Coyote said

    All: Good comments. Some cracked me up! I was expected more comments aimed directly at the basic project design laid out in the post, but I am sure that will come. Now on to specific replies.

    Steve Smyth: If you read through this website, look at the Wiki entries for space solar power, and review the reports posted by our very good friends at the National Space Society at http://www.nss.org/settlement/ssp/library/index.htm you will discover most of the arguments for and against space-based solar power. To sum up, we think that in order to make space-based solar power economically viable that we need to put satellites at geostationary orbit that can broadcast to earth 1 to 2 gigaWatts of power. There will be path loss. We know that. As a result, we think at this time that we need roughly 12km2 of solar array per satellite. This requires considerable mass to be lifted. We are doing little experiments now in order to generate a set of real numbers for us to scale our concept from paper to space. All that said, we will eventually need a small, manned spacelifter that can take assembly workers and inspectors to these behemoths in their assembly orbits in LEO and the operating stations in GEO.

    Scot4space: A school in the Swill Alps contacted me and suggested that they could provide observations and element sets…and I said sure! We’d love that! Perhaps this will catch on. It is really important to spark imaginations with this project, as you have surmised. I am really liking the little satellite because it lets everyone in the world see the light and proves the concept. I really need to go see the folks at NASA and discuss this with them.

    David C: It is, indeed, and LED that we will be illuminating for exactly that reason–we don’t want to waste energy. I am thinking a green LED would be best. What do you think?

    Dr Feng Hsu: Ladies and gentlemen, we are honoured to have the esteemed Dr Feng Hsu follow our progress! Hello, good friend, how are you? All is well here at the University of Reading where I am working on my PhD in Strategic Studies/International Relations. My doctoral thesis is titled “Spacepower and the State.” Basically I am writing a spacepower theory whose central arguement is that “space is for business and government’s job is to enable and protect space commerce.” From this simple statement flows the proper organizational roles for our spacefaring organizations, agencies, and departments. It is only obvious to point out that our space efforts in the US are badly scattered–which is probably the key reason we, as a nation, have not made tremendous progress on SBSP! But it appears that space programs around the world suffer the same problem. Eh, it’s a theory. Yes, I am in touch with Paul “Plato” Damphousse regularly. I am aware of the NASA/ISS experiments, but not fully up to date on them. Is Plato the right guy to discuss this with? Who at NASA might be helpful? As always, good doctor, your participation here always welcome! Thank you.

    Neil Cox: Good comments back to Steve Smyth. By the way, your name always makes me think of Neil Armstrong, the first man on the Moon, and Ken Cox the guy who devised the digital computers for Gemini and Apollo. I guess I just have space on my mind a lot these days. Always good to hear from you.

    David Treece: Wow, SpaceDev. Yes, they do have an “impressive portfolio.” I learned that quoted phrase early in my assignment at Dream Works when I arrived there in 2005. Before then I would have said, yes, they do “a whole bunch of wicked cool stuff!” It’s the difference between being a professional and an enthusiast. I will be meeting with my team of “evil scientists” (foreshadowing) in early December to discuss these matters. I need to see what in-house expertise we’ve got before I go to the commercial pros. We are doing this for education sake, even though we are doing ground-breaking work. But, sure, I’d like to meet these guys and discuss matters over beer. I’m not sure I’ll be able to afford more than bar talk with them, but they are a great team of commercial folks who I cheer on at every opportunity. We are all saddened by the loss of one of their founders, Jim Benson. He was a great guy and shared our great vision for more commercial space activity…only he was brave enough to step out and DO it!

    Robert: General Physics, eh? I am not familiar with your company, but your site is rather impressive. As I told David Threece above, this is an education project and I’m pretty sure I’ve got to exhaust the talent that we can tap on the government payroll first, but I am not sure about that. That said, I think contributions to out educational effort are tax deductible. As for me, I typically pay for services in beer…served mostly at Irish pubs. But this is a great project to be involved with. Let me think about opportunities for us to collaborate. The more friends we have working together, the better!

    Steve Smyth: Hmmmm…I’m not so sure the Space Frontier Foundation is allowed to host commercial advertisements or solicitations on this WordPress website, so we’ll just say you were very briefly pointing out other options, to include some business case considerations and coast scaling. That’s how I read that. Chuckle.

    Robert: Ambassador Roger Harrison, the Director of the Eisenhower Center for Space and Defense Studies at YOUR United States Air Force Academy is working on how accept your tax-deductible contributions to fund this project even as we speak. When he figures it out (which I hope is soon!) I will make it a featured posting on this site. Now, does anybody out there know how we can get cans for change and place them in stores all across America? I would like every Mom, Pop, and all the kids to know they have a piece of this!

    All: You folks are great. Thanks for your thoughtful (and not so thoughtful) contributions to this site, and for a couple of laughs, which are always appreciated. It only works because of you. If you have a spouse and he or she is wondering what you are doing on the computer for so long, tell them the truth; you are working for me on a special government project of the highest importance to humanity that provides one possible solution to our energy, environment, space program, security, and educational goals problems.

    Cheers!

    Coyote

    P.S. I wish all of you could join me at my favourite pub, the Hobgoblin, at town center in Reading for a pint! In fact, if you make the trip I will buy the first round, but don’t all come at once. In fact, don’t come in teams of more than three, unless you are willing to go in on a kitty.

  14. Iyar Binyamin said

    That is great news, to bad for ITAR the aerospace engineering students at the Technion (Israel) would love to take a part in this project.

    How many universities US are participating?

    Iyar

  15. Apparently solar cells with 100% efficiency are now possible:

    http://www.tgdaily.com/html_tmp/content-view-39807-113.html

  16. Coyote said

    Iyar Binyamin: ITAR, which I hate with a passion (wihwap), is a serious impediment to international cooperation (and business) on so many levels, but I won’t go into that here. We need to find a way to allow people around the globe with interests in energy, environment, space, and business development to get involved that does not involve ITAR (wihwap). Perhaps universities and amateur astronomers could help with observing the satellites and posting their element set. If we have an on-orbit anomaly, we will be most grateful for any and all observation data to help us figure out what is going on. If you would, please give this some thought and share whatever ideas you have with us. Feel free to brainstorm here, as that is what this site is all about!

    Rocky Persaud: Besides the Air Force Academy itself, there are six different universities participating. As soon as those universities give me the thumbs-up to announce them formally as part of this project I will post it here!

    Cheers!

    Coyote

  17. Geoff Pritchard said

    Instead of a satellite, why not use a high-altitude balloon for this demonstration? It looks like you could achieve the same goals for a fraction of the cost.

    From typical balloon altitudes of 20-40km, the power beam would still have to traverse almost all of the atmosphere, so the technical challenge is essentially the same.

    Check out the Wikipedia entry on ARHAB (Amateur Radio High Altitude Ballooning) to get an idea of what is possible.

  18. Coyote said

    Geoff Pritchard: If this were only a demonstration of power beaming using a balloon would be fine. However, we are also trying to go through the doors of the national and international licensing and regulatory bureaucracy to see how that is done. This way we can open the doors widely for commercial ventures into space-based solar power to follow. Also on our minds is generating some public excitement about space and space-based solar power in particular. Most importantly, this is an educational project for Academy and university students who are studying various aspects of spacefaring. For them, this is mostly about designing, building, launching, and operating satellites with mission payloads. Thanks for your comment. I’d like you to stay in touch. I like people who see alternatives. We need your kind of thinking. It is entirely possible that those of us who are “too close” to this project will stop seeing the trees to the forest and we’ll need you to point them out to us.

    Cheers!

    Coyote

  19. Steve Smythe:
    >>What is the advantage of gathering Solar Power off planet?
    The satellites can be positioned where there is no weather and no night – photons will always fall on the collectors at a near constant rate, making it a predictable supply.

    >>Are there extra free electrons in Space?
    Probably, but what we’re looking for is the continuous supply of photons.

    >>Is there something RE collection/transmission that makes the Space based >>gathering of Solar Power efficient?
    Not really, except in comparison to solar cells on earth where clouds, dust, and nighttime degrade their efficiency.

    At current costs, a commercial size solar power satellite is estimated to cost the same to implement as a nuclear reactor. Many folks are hoping to implement dozens of new reactors – perhaps some of that money can be used on this type of project instead.

    Have fun,
    Adrian

  20. Jim Cline said

    It is very encouraging that some definite plans for hardware to be put into orbit for the purpose of beaming power down to the ground and lighting a LED, to show proof of concept. Actually, when you think about it, whenever someone has their TV show seen via a satellite dish, they are already receiving solar-derived electrical energy beamed down from GEO; albeit a miniscule amount of energy, it is true solar-electric energy beamed down from space. And there are psychological considerations re lighting a bulb powered from space, for helping people to consider something actually possible instead of just another wacky idea.

    I have witnessed beamed microwave power demonstrations by Bill Brown in 1995 and 1997 at the SSI conferences at Princeton; and one later in Los Angeles at a Space Frontier conference shortly before he passed away. It works. The concept has captured my imagination since the 1960’s; and ever since then I have had a personal goal of looking for ways to put them up there efficiently and economically.

    To make sense, most likely in the long run much more power must be obtained from a power source than one puts into it. And potential quantity resulting needs to be a reasonable goal, delivered to the point of need. While overall cost savings such as lack of need for installing transmission lines may make it overall cost effective to put more overall energy into a particular power source than one can expect to receive from it, for the vision of supplying terrawatts to the countries of the world to enable clean abundant electrical power for them on into the future, the energy used to put them in place and to maintain them there, needs to be a lot less than the total energy they will eventually deliver to the customers. Such a path to feasibility needs to be shown, and that is the purpose of this post. This is not to refute the necessary initial use of conventional launch vehicles for placing construction materials for building some demonstration SPS surely is necessary.

    The potentials and weaknesses of using vertical so-called Space Elevators for economical transportation for building Solar Power Satellites has been seriously explored since 2002, of course; the tensile strength to mass ratio of tether materials is the long-standing key issue there, but not the only issue.

    Again, to show a potentially feasible long range reason for SPS to the world’s nations, as a replacement for dwindling environmentally disruptive fossil fuel energy sources, a fairly complete potential path needs to be shown to reach the full goal of facilities for long range reliable continuous delivery of many terrawatts of solar derived energy beamed down to customers around the world.

    And to that purpose, I would like to point out the principles of what appears to be such a transportation system, potentially able to achieve sufficient construction materials throughput for such a task, potentially approaching a transportation energy of less than an order of magnitude above the 15.7 KWh/kg energy added to payload by having moved it from the earth’s surface equator up into Geostationary Earth Orbit.

    Although there have finally been published peer-reviewed technical papers published describing the concept (in space conference proceedings by ASCE in 2000, 2002, and 2004; and SESI in 2005) the concept has been highly unpopular with established space businesses; unfortunately apparently seen as a suppress-able tough rival instead of a potentially near-future tremendous boon for their space industries.

    It would be an electrically powered transportation system operating between the earth’s surface on the equator, delivering payload specifically to GEO; and being electrically powered, it could be powered by SPS energy eventually, providing long term sustainability.

    It would be a structure whose weight is supported by kinetic energy stored within itself, and would be in the general shape of an ellipse resembling and orbital transfer trajectory from the ground up to GEO; and it would deliver the transportation energy all along itself to lift payload-carrying spacecraft up to GEO and gently lower them back down to the ground. It could take several different specific forms, each with their own natures; but the one I have been mostly writing about since 1989 would be in the form of a synchronous electrical motor with myriad of discrete armature segments sliding around at 10’s of Km/s along inductive maglev tracks inside an evacuated set of quasi-elliptically shaped tubes encircling the earth; the armatures traveling at velocities sufficiently above Orbital Transfer Velocity that their aggregate outward centrifugal force on the track structure balances the force of gravity on the earth-stationary track structure, to support its weight and that of the live loads traveling along it to and from GEO. The armatures would also use a small fraction of their energy to inductively drag the captive spacecraft up from ground to GEO, thus the spacecraft would lift no fuel’s weight for the trip, enabling the extremely high transportation efficiency as compared to conventional launch vehicle transportation from the ground up into GEO.

    With such a transportation structure between ground and GEO, built initially for delivering the construction materials for building an adequate amount of Solar Power Satellites in GEO, and maintaining them there, a host of other utilization of such access thereby become possible, such as high spaceports for reaction engine propelled spacecraft to go out further in space, such as to the Moon and Mars, electrically lifted up to spaceports far beyond the atmosphere and already 91% up out of earth’s gravitational energy well; large scale solar powered mass-spectrometer type total recycling plants might also be built in the zero-gee hard vacuum environment there in GEO too.

    If the conference proceedings’ technical papers are not readily available, some information can be easily read online as a result of my
    “handmade” efforts to create websites at http://www.escalatorhi.com and http://www.kestsgeo.com; where both the technical descriptions and some of my space conference powerpoint presentations, and even my science fiction novels about these and other related ideas, can be found. Most of my life’s personal interest technical creativity efforts have gone into the making of ways to put Solar Power Satellites into GEO economically, ever since first hearing the SPS concept in the 1960’s.

    I write this in hopes it will help you and others to show a potentially full path to total feasibility of powering civilization from space-based solar power, toward which you plan on building hardware to demonstrate solar power beamed down from orbit to light a LED, hopefully to light up more people’s awareness to the potentials.

    Cheers,

    Jim Cline

  21. hey…I haven’t looked for a few days…now we’re getting somewhere…my comments may seem humorous, but they are for real…as a space nut from way back, I’d love to see solar arrays rising in the evening next to the Moom…but, there is no viable excuse for such…Earth based Solar Collection could move forward by leaps and bounds with the $ slotted for this effort…even if it isn’t much, I am afraid it’s wasted on Space Solar.
    why can’t anyone answer the question RE WHY?
    there is no advantage…economic, nor explorationwise…
    how many of those involved in this discussion even realize how Solar Collection works?
    getting closer, out of atmosphere, and hotter has no effect…it’s the free electrons, not the heat…betcha can’t find one person in ten who realizes this…betcha!
    it’s like the Solar Sailor concept…hype based upon ignorance…even those involved in the projects thought Solar Sailing was involved with Solar Wind, not just a big sail collecting solar energy and powering the vehicle…that’s for real!
    there’s a long way to go, Kids!

  22. D said

    If it was done with a balloon you would surely have someone turn around and say “but it’s not space, you haven’t demonstrated anything”.

    Good luck with it and have to agree in regards to ITAR. If that wasn’t an issue I’d be sending a message to the head of engineering at a few local unis and pointing them in your direction. Funny though that the US is quite happy to work with our country on things like a scramjet but not rockets and SSP.

  23. Soroush said

    Hello,

    I am really glad that such an effort is finally taking place on this level. We are a team of students at Stanford University that are working on almost the same project with a few technical differences from yours. I would be glad to learn more about your team and maybe even look into some collaborations, if possible. Send me an email at ssalehian@gmail.com if you are interested.

    Cheers,

    Soroush

  24. John Westerhoff said

    Coyote: Just found the site today. Looks great!

    On the discussion of satellites vs. high-altitude balloons, they both have their place for these kinds of demos. There are a lot of experiments that can be done related to power-beaming that can be done from balloons. But for public interest and visibility, there’s no substitute for space!

    A balloon launch may be useful to consider as a contingency though, in case a ride on a launcher falls through.

    Cheers!

    John Westerhoff.

  25. Jim Cline said

    Although the goal of beaming enough solar energy derived power down from space , as envisaged by Coyote’s project, is not the first physical implementation of delivery of useful amounts of solar satellite derived power down to the earth’s surface – as previously pointed out, that is already being done all over the world, wherever there is a satellite dish aimed at a communication satellite in GEO right now, getting a TV program’s signal, is receiving solar energy picked up by solar panels located ing GEO and being converted into EMF energy and transmitted down to earth and being picked up on the ground at one’s satellite dish, the usefulness being not to light a LED but to provide the information bandwidth to the receiving antenna – there would be huge leaps in technology advancement by the project envisioned by Coyote. That is because Coyote’s project would deliver solar-derived useful power down to earth from a low earth orbit satellite, which means it adds the parameters of focusing a tracking beam linking two relatively moving points.

    In the original concept of the Solar Power Satellite, the transmitter in space and the receiving antenna on the earth surface are relatively motionless, so the tracking requirements are much lower than those of a relatively fast moving focal area as exampled by beaming down from low earth orbit to a fixed location on the ground. Beaming gigawatts down from GEO to a rectifying antenna – usually called a “rectenna” – would need to be focused on an area with a diameter typically 12 miles in diameter, to keep the intensity of EMF energy no more than the sum energy of sunlight received anywhere on the antenna or in the beam coming down through the atmosphere, for safety reasons.

    In the demonstration project, however, the rectenna needs to be quite small; thus the requirement to focus the EMF energy down to a much smaller area. This demonstration capability would be a major step beyond that currently being done by communication satellites in GEO at the present time.

    And being able to track relatively moving focal site could thus enable delivery energy to the ground or in the air from a SPS in GEO, say, to a moving vehicle. In an age where fossil fuels usage on large scale could also hamper its use in large aircraft, such as commercial airliners and cargo planes, the ability to deliver energy to a moving vehicle in the prodigious amounts consumed by a large jet aircraft nowadays, means a much tighter beam and energy density focal area. Such large commercial jet aircraft would be shaped different from conventional aircraft, the swept back leading wing edges becoming a large flat area on top of the aircraft used as the rectenna to receive the power beamed from the SPS in GEO; such aircraft would also need much less energy to propel them since they would not need to lift the weight of the fuel for the trip nor the airframe needed for that; and that converts down to less engine power requirements, electrically propelled aircraft engines in this case; and in fact could be built as supersonic lighter than air vehicles – see my description of this kind of aircraft in my science fiction novel online, http://www.escalatorhi.com/techscifi/it's%20down%20to%20earth.html chapter 22 “A new kind of aircraft” about 3/5 down the long page; actually its description begins in the preceding chapter 21’s end – such large commercial aircraft would thus be able to deliver people and cargo much as today’s large jetliners, except without consuming expensive jet fuel nor its exhaust’s atmospheric contamination of huge amounts of carbon dioxide greenhouse gasses each trip as done nowadays.

    The ability to focus down to focal areas on a moving target bring up the old fears of misuse of the SPS for assaultive purposes, of course. The military uses of such a weapon have long brought caution to people regarding the establishment of SPS in space; memories of such destructive uses of loosed nuclear energy technology are still fresh in our minds, do we want to loose another strong genie out of the bottle too? Yet it is a case of the proverbial “playing with fire” risk; same as the use of fire that brought early man out of savagery; and also into the electrical age we now live in, which was once considered “electrical fire ” – see the 1752 public impression of electrical energy “Electrical FIRE” http://www.escalatorhi.com/JimDabblingH/popelec1752.html – an energy of which somehow we overcame our fear of misuse; and so it now, for example, powers my refrigerator to keep my food from spoiling, and heats my house this cold night and will continue to heat it through the cold winter snows, since we generally learned to use “electrical fire” responsibly – do we want to go back to the days where we had no electrical power to use – I for one am not eager to go back to getting up in each morning in a freezing house to stuff firewood into the potbellied stove, nor to breathe the resulting smokey air outside all day either.

    Similarly we ought to be able to responsibly use power beamed down from space; although we will have to do that consciously and deliberately, hopefully not after some warfare technology race to stimulate its development but rather its wisely intelligent responsible controlled usage by all nations potentially involved, even moreso than the International Space Station project has been. We hopefully have learned to be wise enough to quickly and responsibly learn to safely and responsibly utilize this potentially tremendous new 24/7 power source responsibly, carefully utilizing, instead of “playing with” this new kind of “fire,” a next step for building a civilization based on cheap abundant continuous large scale energy to do our work for us, work far beyond the potentials of man’s own muscles.

    So all these kinds of issues can be explored by the project envisioned as a low earth orbit satellite speeding across the sky, beaming down less than a watt of solar-derived space power to a small area receiver on the ground.

  26. Coyote said

    Adrian_in_Phoenix: Good comments…I’ll add to them when I respond to our friend, Steve Smyth, whom I like very much because he makes us think! People who do that are worth their weight in gold. I wish I had that much gold to pay, but no cigar! Thanks.

    Jim Cline (20): It’s great to have your thoughts on all of this. I agree that to a far lesser degree a communications satellite is doing a similar thing, however, energy is added at the transmitter and the receiver to actually “do the work” of the relatively weak stream of ones and zeros–but you are right, it proves the point on a small scale. Now we need to kick it up a notch. List to orbit and transition to GEO is the big limiting factor preventing space-based solar power from happening. Get the cost to orbit down and simple economics takes over. We are working it, but not fast enough to energize the commercial revolution that will follow such a breakthrough. As for space elevators, I am also suspect. Two shortfalls beset most of the proposals I’ve seen. First, the infinitely strong yes infinitely light material to make it practical is yet to arrive. Carbon nanotubes hold tremendous promise, but we have not yet figured out how to manufacture them to take advantage of that promise. Second, no one had proposed a convincing plan on how to assemble such elevators. I was in London talking to an agent for a world famous insurer (who shall remain nameless)and his concern about space elevators was liability and indemnity if anything went wrong. Good point. I am looking forward to reviewing the papers that you mentioned.

    Steve Smyth: The reasons for space-based solar power are quite simple. First, the sun is many times more intense outside the earth’s atmosphere. This more than make up for the path loss difference of 1/r2. Second, the sun never sets at GEO, other than two 70 dim periods that happen at relative equinoxes each year (at midnight). Third, space-based solar power can be dynamically broadcast wherever it is needed in operational view of a satellite stationed at GEO. That means this power can be broadcast to areas experiencing brown-outs across their power grids, such as California and Europe, and many areas in India and the Pacific rim. It can also be broadcast into those areas with no other infrastructure, such as disaster areas and developing nations. It can also be broadcast to military forces in lieu of their having to haul their energy with them on the ground. Take for example that in Iraq 70% of the logistics train was the movement of petroleum. Also consider that 70% of our coalition casualties were associated with convoying that petroleum. Fourth, we need every source of safe, clean energy we can develop if we are going to avoid resource wars in the future. The demand for energy is escalating at a time when the population is increasing, industrialization is increasing, carbon-based energy sources are considered by many to be damaging the environment, and traditional energy sources are being rapidly depleted with no really good plan to compensate for their exhaustion. That said, we are 100% in support of ALL efforts to develop as much ground-based solar, nuclear, geothermal, hydroelectric, etc. We are just doing our part. Will space-based solar power be more expensive that other alternatives? Yes. But given the reasons stated above, it has unique capabilities that other energy sources do not provide, therefore it is worth pursuing.

    D: There is very little rhyme or reason with ITAR, which I hate with a passion. Your country is a great partner and we look forward to a long, long, long relationship with you. Thanks for your comments.

    Soroush: Thanks! We will be in touch.

    John Westerhoff: You are ever so right that balloons can add to the validity of power beaming. A couple of companies are looking into doing exactly that. However, we are doing this project with cadets and students in space programs. The real goal of this is education, not proving bits and pieces of space-based solar power. As such, we’ve got to build some satellites.

    John Cline (25): I agree. We may all be thankful that if this were a weapon, we would just do it and be done with it. We would not being going on-and-on about it on the open internet. We want this to be done in the commercial sector by publicly traded companies with broad international ownership with broad international customership. The designs we have looked at could not be used as weapons since it is impossible to narrow the transmitting apertures to focus the energy beam sufficiently to cause any harm in a combat sense. A simple pre-launch inspection by international representatives can easily verify this. I my mind, this is about energy to prevent wars, not cause them or fight them.

    Cheers!

    Coyote

  27. cfrjlr said

    steve smyth Says:
    October 22, 2008 at 9:37 pm
    hey…I haven’t looked for a few days…now
    ———
    Steve, space solar power has numerous advantages over terrestrial solar power.
    Over a 24hour period, a solar panel in space will generate 8 to 100 times as much power per unit area as an identical solar panel on the surface of the Earth.
    The 8x to 100x range depends on whether you are comparing with solar panel in a sunny region or in a cloudy region. It also depends on time of year, length of day etc.
    Also…
    Solar panel in space gives constant power output, no storage is required. Solar panel on Earth has unpredictable output and is guaranteed to give zero output at night time. So expensive power storage systems are required or expensive long distance grid connections.
    I hope that helps clarify the issues.
    Thanks,
    Charles R.

  28. Mark said

    I’m sure someone has thought of this already…but – once the satellite testing proves that we can light a bulb on a satellite – why not have the energy sources come from down here and use the satellite to transfer the energy to where it’s needed. I’ve read of the tremendous potential wind energy of North & South Dakota as well the solar energy of the Arizona area. The problem with these areas is that there’s no local market for the energy and there’s no infrastructure to transport the electricity to major centers. (I read about how a wind farm in New York State had to shut down because the local grid couldn’t handle the excess electricity.) I don’t know about the energy loss involved, but these remote, yet energy-rich areas, could have the energy sent up by laser to the satellite and then redirected to where it’s needed. It would be “Space Transmitted Power”. This approach would bring immediate results and attract investment into developing these remote areas. It could definitely be viewed as an initial phase that would eventually include energy being generated in Space as well.
    One application of this could be to beam the electricity to airports. The energy could be used to hydrolyze water on-site into liquid hydrogen as new planes convert to the new fuel. (People may be uncomfortable to fly an electric plane with no onboard fuel that relies on direct energy being beamed from a satellite over the Atlantic. I would.)

    thanks for yout time,
    Mark

  29. Coyote said

    cfrjlr: Well said.

    Mark: Yes, that idea has come up a number of times. I discussed this concept at some length with Ivan Bekey, the author of Advanced Space System Concepts and Technologies: 2010-2030 (Aerospace Press, El Segundo, CA, 2003). Ivan was our own John “the Evil Dr” Mankins’ boss at NASA during their latest Fresh Look study. The idea of bounding energy off of balloons or satellites was first postulated by a German scientist, I think his name was Heinz Eriki. The major problem with the concept is path loss. You will lose ~75% of the power by sending it up to a satellite and back down to Earth. Ivan has looked at it quite favourably. He believes the concept has legs. He sees opportunities for hydroelectric dams in remote locations to broadcast power to other locations in just such a manner. You bring up Dakota winds as another form of generating power for just such a venture. Having lived in Rapid City for six years, I can tell you that there is a lot of wind going to waste there! Anyway, I think the idea has merit and should be pursued. The discussion hosted on this website, however, is not about other alternative energy sources, rather we are seeking a way ahead for space-based solar power. Once we can distill the truth about space-based solar power then we will be in a better place to compare it to other energy sources. We strongly advocate that all other sources of safe, clean energy be developed. We need all the energy we can get. I do not believe space-based solar power is in competition with other energy sources because the future demand for energy will be so great that all sources will be welcome.

    General Comment: I am getting lots of emails and phone calls from folks wanting to discuss the business case. This is critical. We all need to keep in mind that the business case for space-based solar power requires a clear and unambiguous demonstration that the performance gained by going to space more than covers the investment difference between SBSP and say other sources of safe, clean energy. Policy makers, Bankers, insurers, and investors deserve the best numbers we can generate to help them make appropriate estimations. In the end, theirs is the community that will decide the future of space-based solar power. No one here is arguing that we must do space-based solar power even if it will break the piggy bank or fails to provide suitable amounts of safe, clean energy. We have our work cut out for us.

  30. Robert said

    Good luck with the demonstrators. Looks like the numbers will either fall into place or not over the next several years. Space solar fans can contribute in the realm of education while advocating the mix of energy solutions. Interest rose when gas was $4.00. Today it’s $1.89. Go figure!

  31. Robert said

    The last two sentences of an article dated 12/1/08 “Obama May Cancel Space Shuttle Replacement” by Brian Berger for Space.com and appearing on foxnews.com today are very interesting. They indicate the Obama NASA transition team’s interest in three developments that will be useful for SBSP: the Triana earth-observing satellite (Deep Space Climate Observatory), a $100M project that was proposed in 1998, built, and slated originally for the ill-fated Columbia mission in 2003 but voted down by Congress and placed in storage at a cost of $1M/year; NASA efforts at cataloging earth-crossing asteroids; and the harnessing of space solar power for use on Earth. I’m delighted to see that Lori Garver is leading the Obama NASA transition team.

  32. Clarence said

    Steve Smyth

    At the beginning of this thread you asked why gather the energy in space against on the ground. I didn’t read all the replies so this might have been addressed, but long term it is clearly the best idea as the Earths atmosphere filters about 80% of the energy in the suns light before it hits the ground, because of lights wavelength. If we were to collect the energy before it is beamed down we could convert the energy from light to microwaves, which has significantly lower losses in the atmosphere. So the idea is you lose 80% of the solar energy (before capturing) by collecting on the ground and lose 5% or so (hopefully) because of microwave losses.

  33. Clarence said

    Also, this system could potentially provide power to a satellite, spaceship or lunar colony at the same cost (minus the cost of building and maintaining a receiving array) as on Earth

  34. Robert said

    As Gerard K. O’Neill said in his “Alternative Plan for U.S. National Space Program”, NASA is in great need of a new “tiger team” of the caliber that accomplished Kennedy’s moon goal within a 10-year time span. Stand your ground Lori Garver. Presdident-elect Obama, bring on the new tiger team.

  35. Iyar binyamin said

    How are we doing on this? any new information?

  36. Larry said

    One of the reasons for Space Solar that I haven’t read here, but have read in other places, is that it is relatively limitless power. I read somewhere that if you put a 1km band of solar around the entire earth in GEO (I know it’s a lot, but stay with me here), you could collect in one year the equivalent of the Earth’s ENTIRE fossil fuel reserves. It doesn’t run out, and it doesn’t produce pollution. I can’t think of another future power source with those characteristics:
    1. no pollution
    2. completely renewable
    3. As much as we need. Forever.
    4. Safe
    All the best to you. I think you are pioneers of the energy source of the future.
    Personally, I think you’ll need the space elevator to make it financially viable and to the ultimate scale we need it to be, but a lot of progress is being made there too.
    On that note, they are talking about making the elevator tether out of carbon nano-tubes, which I understand to conduct electricity. Um, might this be a safe/efficient means to transmit power back down to earth?

  37. johnmarburry said

    Space-Based Solar Power: Right Here, Right Now?
    John Marburry

    The recent release of the National Security Space Office (NSSO) examination of space-based solar power (SBSP) (NSSO, 2007) in combination with ever more volatile energy prices and increasing concern over dependence on foreign sources of energy has given rise to refocused attention on the idea of beaming energy from space via satellites orbiting the Earth and collecting energy from the sun. Though this idea may sound like science fiction to some, it was first proposed by Peter Glaser in his groundbreaking paper “Power from the Sun: Its Future” in 1968. Since that time, the concept has undergone several rounds of investigation by agencies including NASA, the Department of Energy, and, most recently, the NSSO.

    Obviously, the idea of tapping into the near limitless power of the Sun to achieve greater energy security is tantalizing, even to the casual observer. All else being equal, the benefits of an effective SBSP are potentially enormous, ranging from the revitalization of the beleaguered aerospace industry to a means of reducing global emissions of greenhouse gasses. As is the case with all public policies though, all else is not equal and one must ask if it is truly the right time for the United States to embark on a project of such epic proportions such as SBSP.

    At this point, it does not seem to be an understatement to say that the American economy is teetering on the edge of disaster. This is evidenced in no small part by ever expanding federal budget deficits, the seizing-up of credit markets for everything from new cars to large infrastructure projects, and increasing levels of unemployment. The issue, then, is not whether an effective and efficient SBSP system could provide the U.S., not to mention the rest of the world, enormous benefits but, rather, if using up scarce federal funding and investment dollars for a project of the scale and cost of SBSP is the wisest course of action at this moment in time.

    With the economy closer to the abyss of complete economic Armageddon than it has been at any point since, perhaps, the Great Depression, the last thing we need is to start throwing money hand over fist at a project that might end up being nothing more than a pie in the sky fantasy. To this end, its seems increasing likely that the new Obama administration and Congress will enact some form of green stimulus program aimed at bolstering terrestrial solar, wind, and other so-called alternative energy programs. The hope in enacting this type of stimulus will be that such federal assistance will help drive investment dollars towards green energy projects that hold the potential to keep the American economy out of complete economic demise, get people back to work, and shore up America’s international technological and economic competitiveness.

    The issue with investing in SBSP at the current juncture is not that it would not produce similar, if not greater, positive economic outcomes. The issue is, rather that those positive economic results will to be felt for some time whereas investments into terrestrial green energy projects can be rolled out and started in short order with near immediate economic benefits. By the NSSO’s own estimate, SBSP technology will not be mature enough to supply a mere 10% of America’s baseload power needs until 2050 (NSSO 2007, p. 9). Even though SBSP could end up producing enormous benefits for all of society in the decades to come, we can not allow the best to become the enemy of the good.

    The danger in making large investments into SBSP while the economy is reeling is that there is only so much money to go around. As such, there is a danger that scarce investment dollars will be siphoned way from more immediately viable and beneficial programs such as terrestrial based green energy programs. The Department of Energy reported in its review of SBSP that “every dollar spent on solar satellites will not be spent on terrestrial research and commercialization” (DOE 1978, p. 15). Unfortunately, it is these very programs that may be critical to preventing a complete collapse of the U.S. economy. It would be nothing less than a tragedy of political judgment if the country was forced to forgo the near-term economic benefits of terrestrial green energy programs simply to fund a SBSP program that will not be viable for years, if not decades.

    The NSSO tangentially addresses this issue in that the report argues that the Department of Defense (DOD) should serve as the driving force behind SBSP development. The NSSO, rather simplistically, contends that the DOD is one of the only federal agencies for which SBSP currently makes economic sense. The NSSO reaches this conclusion by asserting that the military would achieve substantial cost savings by utilizing SBSP for overseas operations instead of continuing to bear the costs of traditional sources of energy that the NSSO estimates at approximately $1 per kilowatt hour. As such, the NSSO report concludes that the DOD should move forward with further investments into research and development of SBSP.

    The report, unfortunately, seems to overlook the fact that defense budgets are already stretched thin given continued operations in Iraq and Afghanistan in addition to the overall tightness in the broader federal budget. If the DOD were able to make investments into research and development for SBSP today and begin receiving energy beamed from space tomorrow for a price below that of its current energy supplies, such an investment would make sense. Yet, even with massive investment by the DOD into SBSP today, military units would not start being able to utilize these power sources for years.

    As such, the problem with DOD investments in SBSP in the short term is that the military will end up having to pay not only for its traditional energy supplies but will have to also carry the extra burden of funding SBSP research and development costs. With readiness, maintenance, and procurement accounts already stretched thin, this is simply a situation the DOD can not afford. In a worst case scenario, a mandate to pursue SBSP research and development could force the military to drastically scale back, if not cancel entirely, critical programs such as the F-22 Raptor to pay for an energy system that it will not be able to use for decades. It should go without saying that gambling with our national security today is too high of a price to pay for a source of energy that is decades away.

    These arguments aside, there are clear benefits associated with the successful commercialization of SBSP. More importantly, there are proactive steps the government can take to help facilitate such an outcome that do not sacrifice the needs of the nation today to give it what it wants tomorrow. For instance, the DOD could announce, through formal agreement if necessary, that it is willing to become an anchor tenant for commercial power beamed from space at a cost at or below $1 per kilowatt hour.

    Such an announcement and/or agreement would help drive private investment dollars into SBSP research and development as the economy begins to regain its footing. In short, investors would be compelled by the prospect of having an assured customer for the product should they successfully commercialize SBSP. Such an agreement would not require any federal outlays in the short term. Obviously, should industry begin to show progress towards accomplishing the goal of beaming energy from space at a cost at or below $1 per kilowatt hour it will become increasingly likely that the government will begin to supply additional investment capital down the line without running the risk of an economic boondoggle today.

    Were the DOD to undertake such an initiative, it is important that the military make it exceedingly clear that it is merely agreeing to purchase commercial power beamed from space and that it is not funding nor will it own any portion of the space-based solar power systems. This level of clarity is important to prevent the international community from misperceiving our intentions. It takes no stretch of the imagination to realize that one of the fears associated with SBSP is the possibility that it will be used as a space-based weapons system. Making it clear that the DOD is merely agreeing to purchase commercial power from space and not the actual space-based solar power systems should help allay these concerns.

    This issue has little to do with the actual need for space-based weapons systems. Even for proponents of building and deploying space-based weapons doing otherwise makes little sense. Were the DOD to create the international perception that it is purchasing or funding space-based solar power systems, it is likely to fuel the fear that the DOD is actively pursuing the weaponization of space. Sending such a signal to the international community is likely to give further impetus for countries to develop their own brands of space-based weapons as well as the capabilities to destroy space-based systems from Earth. The danger is, then, that other countries are forced into a position of weaponizing space before the United States embarks on such a path but is then forced to in an attempt to respond to the actions of other nations.

    This scenario could set off an action-reaction cycle that heightens the risk of a space-based arms race and all of the dangers that would pose to international stability. As such, preventing the international community from misinterpreting our interests in pursuing SBSP could be seen as an important means of preserving our dominance in space simply by not giving potential military competitors reason to ramp up their own space-based weapons programs. This, then, will allow the United States to pursue, if it chooses such a path, a space weapons program at its own pace instead of having its hand dictated by the actions of other nations.

    It is also important for the DOD to place clear conditions on the price it is willing to pay for power beamed from space. As was discussed earlier, the NSSO believes that the DOD would be able to achieve cost savings if it were able to acquire power from SBSP systems at a price of $1 per kilowatt hour. Placing this price condition in any agreement for SBSP is important for two reasons. First, the condition will provide an added incentive to drive down the cost of beaming power from space. Obviously, this will increase the likelihood of the full-scale commercialization of SBSP by making it affordable for entities beyond the DOD.

    Second, were the DOD to make an unconditional agreement to purchase power from SBSP systems, industry is likely to take advantage of such an offer and pass along the majority of the costs for research and development to the military by charging exorbitant costs for the energy. This would force the DOD, again, to siphon resources from readiness, procurement, and maintenance accounts to pay for the project. In the same way that the DOD does not have the funds to pay for SBSP research and development outright because such funding runs the risk of forcing cuts to important programs such as the F-22 Raptor, it also does not have the funds to pay for the research and development of SBSP pushed through the back door.

    If there were such a thing as a money tree and the American economy were not in dire straights it would make perfect sense for the government to embark upon an all-out path towards the development of space based solar power. Unfortunately, money trees only exist in our dreams and, quite simply, the nation currently has better uses for the money that would need to be spent by funding SBSP research and development. Fortunately, however, there is a more moderate path the government can take, agreeing to purchase commercial power beamed from space, which does not require any federal outlays in the near-term but will effectively help speed the development of SBSP. This is one case where we might be able to have our cake and eat it too.

    John Marburry holds a B.S. in Political Science, a B.A. in History, a M.A. in Political Communication, and currently serves as an independent policy analyst. He can be reached at john_marburry@hotmail.com.

    References

    Department of Energy. Satellite Power System (SPS): Public Acceptance. HCP/R-4024-04, October 1978. Available at http://www.nss.org/settlement/ssp/library/1978DOESPS-PublicAcceptance.pdf.

    National Security Space Office. Space-Based Solar Power As an Opportunity for Strategic Security: Phase 0 Architecture Feasibility Study. October 2007.

  38. Robert said

    Our economic standstill is caused by two-dimensional thinking and policymaking. When our sites are terrestrial, we do what we think is reasonable and spend $20 billion on fusion research, for example, without an economically useful result fifty years after starting it.

    We successfully build our civilization on oil and sooner or later find ourselves near the end of that finite supply. Because of political and cultural differences, we are at odds with supplies from the middle east. We successfully make fission and coal work for us, but they are hazardous and are, at best, feeder strategies into future global demand.

    This is not the season to wait again for a decision to go forward on federal research and development into space solar. This is the season to progress, and we have at the helm a progressive President.

    The arguments pro and con about space solar are reflected in the arguments about stimulus: the math either says yes or no depending on who does the mouthing.

    Is math all there is?

    Knowing that the hard research is necessary, and that public fear is a real motivator to unify and rally beyond politics, a progressive President could announce a space-based solar power program by painting a simple non-math oriented picture. He could call for us to build a new city off the surface of the earth. Some of us will remember the artists’ impressions of the city that have already been painted, and be satisfied. Younger ones can be educated on it, and they will find it on the internet as well, and be amazed.

    Yes, we know what the factory towns were like that were constructed to comfortably house our nation’s builders. It’s time to build a factory town outside of the two dimensions that define our misery.

    Let the math serve the vision, rather than the other way around.

    Robert Sugg
    General Physics Corporation
    Elkridge, MD

  39. Raymond N. Cox said

    I agree except USA should reserve the right not to purchase the power from space, if the project makes use of mostly non USA facilities and/or non USA workers. Neil

  40. Raymond N. Cox said

    If I understand correctly, CNT is a good electrical conductor, but not better than copper, by cross sectional area, perhaps not better by weight. Copper is not good enough to transmit electricity economically 36,000 kilometers. It is unlikely CNT will be less costly than copper. Worse the binders expected to be used for the space elevator ribbon are poor conductors, so the ribbon will likely be a poor conductor of electricity. Also worse optimising the ribbon for electrical conductivity will reduce it’s strength and ability to survive atomic oxygen, micro meteorites and small space junk. Neil

  41. sunny said

    People like you should be given a break and full support. I am in favor with your ideas. Let’s go green and support this kind of ideas.

  42. Hey Folks,
    Long term should we be looking at a space elevator to act as both low cost lift and possibly a nice fat cable for power? Sure would employ a pile of folks….
    Farmer Mark

  43. Raymond N. Cox said

    A reputable study concluded that sufficient spinning reserve has already been built = natural gas powered alternators, that 22% of USA electricity can come from wind turbines, or early SSP which may not be reliable.
    If plug in electric vehicles charge mostly at other than the peak demand period, we may soon be able to go a bit more than 22%. Also being considered is a means by which power companies can shut off customer heat pumps, electric hot water heaters etc, if the wind pauses briefly, or a major fossil fuel power plant, trips off line unexpectedly. All power plants have built in controls which protect the plant from damage in many scenarios. This is sometimes what is referred to as smart grid. To achieve this 22% plus without increasing the probability of rolling blackouts, many of the links between nearby cities need to be up graded to carry more megawatts. Apparently smart grid also includes some safeguards to discourage terrorist from hacking the computers which control the USA power grid and power plants. I once suggested to the power company, I worked for, that they retain the old controls as back up for the new electronic controls which are vulnerable to EMP = electrictromagnetic pulse which is produced by air burst nuclear weapons, but also by earth quakes, volcanoes and large asteroid hits. 100 years ago the controls were relays, and other electro-mechanical devices which were much less vulnerable to EMP and terrorism.
    The MW for MW back up is not necessary, if the wind turbines are distributed over the 1500 mile length of the wind corridor as the wind will not stop blowing everywhere at once. Even 22% below average is likely predictable hours in advance, if it ever occurs.
    In my opinion, we should be thinking HVDC = high voltage direct current for power lines that bring electricity from the wind corridor to the East and West Coast where most of the customers are located. Wikipedia has a good write up on HVDC. Neil

  44. Bryan said

    Quite an interesting read, I must say. I sure hope that you get this up and going, and I’ll keep checking back for updates!

  45. Ed Pell said

    What is the maximum watts/sqcm you can achieve on the ground from the laser in space? What orbit height is planned? Will you use reaction wheels? How long do you expect your control propellants to last? You are saving up power? How much of the satellite is devoted to batteries? tell me more…. This is a great project. Best of luck.

    Ed Pell

  46. Rob Mahan said

    I was searching for any recent activity on Space-Based Solar Power when I simply happened on the website of Space Energy, a Swiss company with plans to commercialize the concept. Here are their Vision and Mission statements, excerpted from the Space Energy website:

    Vision statementSpace Energy, Inc. intends to become the world’s leading commercial enterprise in the field of Space-Based Solar Power (SBSP) which will improve the lives of millions of people by bringing a source of safe, clean energy to the planet.

    Mission statementTo develop, own, and operate the first SBSP satellites to provide base-load and emergency electrical power to customers around the globe at affordable, fair market prices.

    What we desperately need now is for American corporations and entrepreneurs to apply American ingenuity and start competitive efforts so that the free market forces can forge the best Space-Based Solar Power solutions for the entire planet.

    Rob Mahan
    Citizens for Space Based Solar Power

  47. Raymond N. Cox said

    Hi Ed: With present laser technology, one watt per square cm = ten kilowatts per square meter is likely achievable at sea level from about 300 kilometers directly overhead, so one square meter of photovoltaic panel is enough to keep the batteries mostly charged in most electric vehicles in most situations. We will want to avoid human exposure to the beam as that is ten times the allowable leakage from microwave ovens = rarely dangerous, almost never fatal. Somewhat higher beam density will likely be possible ten years after the first SSP, but possibly not desirable, due to possible injury to humans.
    At 300 kilometers altitude, the Sun only shines about 60% of the time, so batteries will only be sufficient for satellite systems = so rarely power to the ground 40% of each orbit unless battery technology improves a lot.
    A solar synchronous orbit keeps the satellite always in sunlight, and the beam is available almost everywhere on the Earth a few minutes out of most orbits. Only a few hundred watts per square meter is proposed for commercial power delivery to eliminate death ray fears, which are mostly irrational.
    GEO stationary orbit = 36,000 kilometers altitude is mainstream for commercial SSP, but a few people want to beam energy from the Moon or even farther away at Earth-Sun L1
    Ion engines will be likely be used to adjust satellite attitude and orbit, so a few tons of ejection mass should supply a thousand ton satellite for many years. Ion engines use electricity for power.
    Can someone explain “reaction wheels”? Neil

  48. Robert said

    Looks like PG&E and Solaren Corp. of Manhattan Beach, CA are seeking approvals on a deal to deliver the first commercial SBSP! Gary Spirnak, Solaren CEO, is apparently committing to deliver 200MW baseload to the utility by 2016 from a Solaren-designed satellite in geo to a rectenna in Fresno. Spirnak is a former USAF and Boeing satellite engineer who says his design hits the cost mark. Articles are flooding the internet now. Leave it to California to lead on this – let’s hope Obama is paying attention!

  49. Karl Henriksson said

    Hey, have you all seen these posts. This is happening faster than even I dared imagine possible! Yes, I know, there is still a long way to go yet, but when companies like PG&E get interested, something is going on.

    Karl Henriksson

    http://www.next100.com/2009/04/space-solar-power-the-next-fro.php

    http://www.next100.com/2009/04/interview-with-solaren-ceo-gar.php

  50. Raymond N. Cox said

    Space solar power looks puny for the next ten years, but you should never say never. We can do it now, very small scale for about a million times what it costs to make electricity from coal. The main problem is launching mass into space is very costly. Details at http://www.spacesolarpower.wordpress.com Cost will come down if we start doing space solar power, but not enough to make it cost effective, near term.
    How about we use big hydrogen balloons, free flying at an altitude of about 30 kilometers and lasers to send the energy to existing solar energy sites? Low cost at the receiving end. The lasers are expensive, but not nearly as costly as getting mass to LEO orbit or GEO orbit. The lasers can illuminate spots as small as one square meter from a distance of 100 kilometers. Minimum spot size is about one kilometer for radio beams, with a reasonable size transmitting antenna. A square kilometer is about optimum for a gigawatt, but about a square meter is optimum for a kilowatt. In the Northern hemisphere the balloons launched just North of the Equator could be recovered near the Arctic circle, a few months later. Hydrogen is non-flammable above about 10 kilometer altitude because the air is too thin to support combustion. The world helium supplies are inadequate for large scale balloon use. Neil

  51. Ed Pell said

    On the reaction wheel question. If you have a satellite that you want to keep pointing in one direction and it begins to rotate you can do one of two things. You can fire a thruster and counter-act the rotation or you can have a set of three wheels inside the satellite and if the satellite rotates to the “right” you rotate appropriate wheel to the right. This transfers the angular momentum to the wheel from the body of the satellite. So now the satellite is still and the wheel is moving. You can keep doing this until the wheel is moving at its maximum speed. Then you say the wheel is saturated. At that point you need to fire thrusters to dump the angular momentum and bring the wheel to zero speed. The advantage of using the wheel is that 1) very small disturbances can be canceled out and 2) the thrusters do not have to fire as many times (this is important if the thrusters have a limited lifetime of say 200 firings).

  52. Justin Skarb said

    Space-Based Solar Power: Right Here, Right Now?
    by Justin Skarb

    Note: A prior version of this article and contribution to the space solar power discussion forum was previously published under the pen name John Marburry; all qualifications and cites remain unchanged.

    The recent release of the National Security Space Office (NSSO) examination of space-based solar power (SBSP) (NSSO, 2007) in combination with ever more volatile energy prices and increasing concern over dependence on foreign sources of energy has given rise to refocused attention on the idea of beaming energy from space via satellites orbiting the Earth and collecting energy from the sun. Though this idea may sound like science fiction to some, it was first proposed by Peter Glaser in his groundbreaking paper “Power from the Sun: Its Future” in 1968. Since that time, the concept has undergone several rounds of investigation by agencies including NASA, the Department of Energy, and, most recently, the NSSO.

    Obviously, the idea of tapping into the near limitless power of the Sun to achieve greater energy security is tantalizing, even to the casual observer. All else being equal, the benefits of an effective SBSP are potentially enormous, ranging from the revitalization of the beleaguered aerospace industry to a means of reducing global emissions of greenhouse gasses. As is the case with all public policies though, all else is not equal and one must ask if it is truly the right time for the United States to embark on a project of such epic proportions such as SBSP.

    At this point, it does not seem to be an understatement to say that the American economy is teetering on the edge of disaster. This is evidenced in no small part by ever expanding federal budget deficits, the seizing-up of credit markets for everything from new cars to large infrastructure projects, and increasing levels of unemployment. The issue, then, is not whether an effective and efficient SBSP system could provide the U.S., not to mention the rest of the world, enormous benefits but, rather, if using up scarce federal funding and investment dollars for a project of the scale and cost of SBSP is the wisest course of action at this moment in time.

    With the economy closer to the abyss of complete economic Armageddon than it has been at any point since, perhaps, the Great Depression, the last thing we need is to start throwing money hand over fist at a project that might end up being nothing more than a pie in the sky fantasy. To this end, its seems increasing likely that the new Obama administration and Congress will enact some form of green stimulus program aimed at bolstering terrestrial solar, wind, and other so-called alternative energy programs. The hope in enacting this type of stimulus will be that such federal assistance will help drive investment dollars towards green energy projects that hold the potential to keep the American economy out of complete economic demise, get people back to work, and shore up America’s international technological and economic competitiveness.

    The issue with investing in SBSP at the current juncture is not that it would not produce similar, if not greater, positive economic outcomes. The issue is, rather that those positive economic results will not be felt for some time whereas investments into terrestrial green energy projects can be rolled out and started in short order with near immediate economic benefits. By the NSSO’s own estimate, SBSP technology will not be mature enough to supply a mere 10% of America’s baseload power needs until 2050 (NSSO 2007, p. 9). Even though SBSP could end up producing enormous benefits for all of society in the decades to come, we can not allow the best to become the enemy of the good.

    The danger in making large investments into SBSP while the economy is reeling is that there is only so much money to go around. As such, there is a danger that scarce investment dollars will be siphoned way from more immediately viable and beneficial programs such as terrestrial based green energy programs. The Department of Energy reported in its review of SBSP that “every dollar spent on solar satellites will not be spent on terrestrial research and commercialization” (DOE 1978, p. 15). Unfortunately, it is these very programs that may be critical to preventing a complete collapse of the U.S. economy. It would be nothing less than a tragedy of political judgment if the country was forced to forgo the near-term economic benefits of terrestrial green energy programs simply to fund a SBSP program that will not be viable for years, if not decades.

    The NSSO tangentially addresses this issue in that the report argues that the Department of Defense (DOD) should serve as the driving force behind SBSP development. The NSSO, rather simplistically, contends that the DOD is one of the only federal agencies for which SBSP currently makes economic sense. The NSSO reaches this conclusion by asserting that the military would achieve substantial cost savings by utilizing SBSP for overseas operations instead of continuing to bear the costs of traditional sources of energy that the NSSO estimates at approximately $1 per kilowatt hour. As such, the NSSO report concludes that the DOD should move forward with further investments into research and development of SBSP.

    The report, unfortunately, seems to overlook the fact that defense budgets are already stretched thin given continued operations in Iraq and Afghanistan in addition to the overall tightness in the broader federal budget. If the DOD were able to make investments into research and development for SBSP today and begin receiving energy beamed from space tomorrow for a price below that of its current energy supplies, such an investment would make sense. Yet, even with massive investment by the DOD into SBSP today, military units would not start being able to utilize these power sources for years.

    As such, the problem with DOD investments in SBSP in the short term is that the military will end up having to pay not only for its traditional energy supplies but will have to also carry the extra burden of funding SBSP research and development costs. With readiness, maintenance, and procurement accounts already stretched thin, this is simply a situation the DOD can not afford. In a worst case scenario, a mandate to pursue SBSP research and development could force the military to drastically scale back, if not cancel entirely, critical programs to pay for an energy system that it will not be able to use for decades. It should go without saying that gambling with our national security today is too high of a price to pay for a source of energy that is decades away.

    These arguments aside, there are clear benefits associated with the successful commercialization of SBSP. More importantly, there are proactive steps the government can take to help facilitate such an outcome that do not sacrifice the needs of the nation today to give it what it wants tomorrow. For instance, the DOD could announce, through formal agreement if necessary, that it is willing to become an anchor tenant for commercial power beamed from space at a cost at or below $1 per kilowatt hour.

    Such an announcement and/or agreement would help drive private investment dollars into SBSP research and development as the economy begins to regain its footing. In short, investors would be compelled by the prospect of having an assured customer for the product should they successfully commercialize SBSP. Such an agreement would not require any federal outlays in the short term. Obviously, should industry begin to show progress towards accomplishing the goal of beaming energy from space at a cost at or below $1 per kilowatt hour it will become increasingly likely that the government will begin to supply additional investment capital down the line without running the risk of an economic boondoggle today.

    Were the DOD to undertake such an initiative, it is important that the military make it exceedingly clear that it is merely agreeing to purchase commercial power beamed from space and that it is not funding nor will it own any portion of the space-based solar power systems. This level of clarity is important to prevent the international community from misperceiving our intentions. It takes no stretch of the imagination to realize that one of the fears associated with SBSP is the possibility that it will be used as a space-based weapons system. Making it clear that the DOD is merely agreeing to purchase commercial power from space and not the actual space-based solar power systems should help allay these concerns.

    This issue has little to do with the actual need for space-based weapons systems. Even for proponents of building and deploying space-based weapons doing otherwise makes little sense. Were the DOD to create the international perception that it is purchasing or funding space-based solar power systems, it is likely to fuel the fear that the DOD is actively pursuing the weaponization of space. Sending such a signal to the international community is likely to give further impetus for countries to develop their own brands of space-based weapons as well as the capabilities to destroy space-based systems from Earth. The danger is, then, that other countries are forced into a position of weaponizing space before the United States embarks on such a path but is then forced to in an attempt to respond to the actions of other nations.

    This scenario could set off an action-reaction cycle that heightens the risk of a space-based arms race and all of the dangers that would pose to international stability. As such, preventing the international community from misinterpreting our interests in pursuing SBSP could be seen as an important means of preserving our dominance in space simply by not giving potential military competitors reason to ramp up their own space-based weapons programs. This, then, will allow the United States to pursue, if it chooses such a path, a space weapons program at its own pace instead of having its hand dictated by the actions of other nations.

    It is also important for the DOD to place clear conditions on the price it is willing to pay for power beamed from space. As was discussed earlier, the NSSO believes that the DOD would be able to achieve cost savings if it were able to acquire power from SBSP systems at a price of $1 per kilowatt hour. Placing this price condition in any agreement for SBSP is important for two reasons. First, the condition will provide an added incentive to drive down the cost of beaming power from space. Obviously, this will increase the likelihood of the full-scale commercialization of SBSP by making it affordable for entities beyond the DOD.

    Second, were the DOD to make an unconditional agreement to purchase power from SBSP systems, industry is likely to take advantage of such an offer and pass along the majority of the costs for research and development to the military by charging exorbitant costs for the energy. This would force the DOD, again, to siphon resources from readiness, procurement, and maintenance accounts to pay for the project. In the same way that the DOD does not have the funds to pay for SBSP research and development outright because such funding runs the risk of forcing cuts to important programs, it also does not have the funds to pay for the research and development of SBSP pushed through the back door.

    If there were such a thing as a money tree and the American economy were not in dire straights it would make perfect sense for the government to embark upon an all-out path towards the development of space based solar power. Unfortunately, money trees only exist in our dreams and, quite simply, the nation currently has better uses for the money that would need to be spent by funding SBSP research and development. Fortunately, however, there is a more moderate path the government can take, agreeing to purchase commercial power beamed from space, which does not require any federal outlays in the near-term but will effectively help speed the development of SBSP. This is one case where we might be able to have our cake and eat it too.

    Justin Skarb holds a B.S. in Political Science, a B.A. in History, a M.A. in Political Communication and currently serves as an independent policy analyst. He first became involved in researching space based solar power in his capacity as an assistant debate coach at Damien High School in La Verne, California. He can be reached at jbskarb@gmail.com.

    References

    Department of Energy. Satellite Power System (SPS): Public Acceptance. HCP/R-4024-04, October 1978. Available at http://www.nss.org/settlement/ssp/library/1978DOESPS-PublicAcceptance.pdf.

    National Security Space Office. Space-Based Solar Power As an Opportunity for Strategic Security: Phase 0 Architecture Feasibility Study. October 2007.

  53. mules333 said

    Coyote, I just found this site. Good show!

    Critical to SBSP is low-launch costs. To go a step further, one must look at cash flow and integrated system costs, where the multitude of capabilities are added together (costs and benefits). It is unlikely that investors will pay for a high-risk, long payback-time, space elevator; however, they have been willing to pay for communication satellite systems.

    Last October, my students presented papers* at the International Astronautics Congress (IAC-2008 in Glasgow) that described an ultra-high-capacity, low-earth-orbit communications system and the follow on, which is a relatively low-cost, low-mass, space elevator (a modified HASTOL system). Based on material and technology available at that time, this “mass lifter” required no new materials, no new technology, and no hyper-velocity aircraft to provide a functional proof of concept. It was estimated that the communication system would be supplementing transoceanic, underseas fiber-optic cables within 5 years of “start,” and its technology and cash-flow would be supporting the mass lifter that would be making its first transfers to space (from aircraft at 40,000 ft) within 8 years.

    * A. Meulenberg, R. Suresh, Karthik Balaji P. S., and S. Ramanathan, “LEO-Based Optical/Microwave Terrestrial Communications,” and “Sling-On-A-Ring: A Realizable Space Elevator to LEO?” Proceedings of the 59th International Astronautical Congress, IAC-2008 Glasgow, Scotland, Sept ’08.
    (I’m presently requesting authorization to post these copyrighted papers on a website.)

    Six weeks ago, they presented “Solar Power from LEO,” at ENVIROENERGY 2009: International Conference on Energy and Environment, Chandigarh INDIA, March 19 – 21, 2009. The initial use for this power is for the mass-lifter (which can also “sling” payloads out of earth’s gravitational field). This conference was as interested in the environmental impact as the power. Rocket power would be used to establish the communications system and then the mass lifter. After that was functioning, rockets would only be needed for the low-g payload requirements (e.g., people).

    Early funding for the SBSP project, before terrestrial power was delivered, would be repaid from “carbon credits.” Estimated costs, masses, and timelines for terrestrial-temperature control (via extremely large-area, thin-film, solar shades), complete replacement of fossil-fuel-based electrical power on earth, and development of a space-based industrial/mining/trading complex would be astronomical. On the other hand, building and powering a new civilization (in space) and powering the old one (all within a century) is not a minor task. Nevertheless, given the right tools and concepts, it is doable – and it would be highly profitable.

    In the 6 months since the first presentation, new high-tensile-strength materials have been demonstrated. These make simpler and significantly less-expensive versions of the systems feasible. In about 5 months, the next papers (on the temperature-profile changes possible and the impact of the new materials on design and costs of the mass lifter)will be presented at IAC-2009 in Korea.

    At this point, any delay in starting the project is time and profits wasted.

  54. Raymond N. Cox said

    It is hard to guess how sling on a ring might be configured without more details. The forum at http://www.liftport.com has analyzed a dozen variations on the space elevator and the hypersonic skyhook. Speeds over about one kilometer per second at 40,000 feet produce material weakening heat and have very high energy loss due to air friction. Very large hydrogen balloons may make two kilometers per second practical at about 100,000 feet, but we still need a large 2nd stage to reach orbital speed, and pass though the rest of the atmosphere and to oppose gravity until we reach orbital speed, altitude, and the correct direction of travel.
    The 66 Indium communications satellites work reasonably well at slightly higher than low Earth orbit. How is your system different, other than lots more channels? Neil

  55. Raymond N. Cox said

    Unless Solaran knows something unknown to most of the SSP experts, they will not supply even one megawatt-hour to PG&E by 2017. Getting solar panels to orbit costs way too much with current technology, and slight possibilities such as the space elevator will be available after 2017, if ever.
    The study in the 1980s proposed a 5 kilometer antenna at an altitude of 23,000 miles, to send energy to a rectenna that covers about ten square miles. Can you imagine the cost of ten square miles near Fresno, California? One trillion dollars perhaps. If we figure there is no upper limit on radio frequencies, same as the color green perhaps? Then the antenna and the rectenna can be much smaller: Perhaps 2000 square meters. That would be 1/10 th megawatt per square meter, which is a death ray, if you can’t escape in seconds. Exposure feels like a raging fever. At the much higher frequency about a trillion rectenna elements are needed. The rectenna diodes may not rectify at less than ten watts per square centimeter = 100 kilowatts per square meter = 1/10 th megawatt per square meter, unless many elements can be series connected to each diode. As far as I know, rectennas have not been designed for frequencies above about 30 gigahertz There are lots of details at http://www.spacesolarpower.com which has a great forum.
    Death ray is not a problem with present technology which likely cannot illuminate a spot smaller than 300,000 square meters from a distance of 23,000 kilometers. That is 1/10 watt per square centimeter = the allowable leakage from microwave ovens = not dangerous. To put 200 megawatts on the grid the beam needs to have about 300 megawatts. There are some losses in the rectenna, the inverters and the step up transformers. Neil

  56. Good idea, but I would probably suggest what Geoff had to say about the high-altitude balloon to lower the cost at least until the idea is profected!

  57. Shubber said

    Awfully quiet here, Coyote…. no posts from you since December. How’re things on the other side of the pond?

  58. Rob Mahan said

    Dear Coyote,

    I would really like to see an update from you on the current state of space-based solar power. Not seeing a new post from you since October of 2008 has had me concerned for a quite a while now. I regard you as one of the most devoted supporters of this energy source and you have given me a lot of inspiration to also support it through Citizens for Space Based Solar Power.

    Are the two demonstration satellite projects still in work? Is everything OK with you professionally and personally? Has a technical discovery derailed the whole idea? Has the change of administrations halted any momentum there may have been or is your silence here simply related to the near collapse of the domestic and global economies?

    I haven’t posted anything new on my site since April of this year. News of several start-up space-based solar power companies (PowerSat, Solaren, Space Energy) has been interesting but their websites are either only background information or placeholders with no news of any real progress.

    Hope to hear from you soon!

    Best regards,
    Rob Mahan
    Citizens for Space Based Solar Power

  59. Neil Cox said

    Hi Geoff and Alternative Energy: If we have the technology to beam energy from balloons with lasers, I agree. Any solar site could receive the laser beam while microwaves require many large and expensive rectennas to be built. This is because tethered balloons cannot reach an altitude of 20 kilometers, but free flying balloons can easily, but they typically change rectennas/solar sites about twice per hour as they are pushed by high altitude winds. At 20 kilometers altitude at least 2 hours more useful sunlight is received each day compared to surface solar sites. As I see it two balloons tethered to each other are launched. One has the photo voltaic panels (pointed at the Sun) the other, the laser array aimed at the solar site on the ground. The beam is moved to a different solar site up to several times per hour. Neil

  60. richard wehe said

    well, the japanese government seems to have a plan. anybody thought out the technical details of using space based power for lunar exploration?

    investors probably won’t pay for long payback times and they probably won’t pay for carbon credits lightly, but they might pay for enabling technologies.

    i have reservations about using the technology for earth-based systems. geosync orbit slots are pretty valuable, i would guess. in addition, large solar arrays are pretty big targets for space junk.

  61. […] Space-Based Solar Power As an Opportunity for Strategic Security, Phase 0 Architecture Feasibility Study, Report to the National Security Space Office, October 10, 2007 – summarized by our own Coyote Smith (one of the study’s authors) here […]

  62. Neil cox said

    On SBSP, GEO stationary orbit will likely be best when we have a million megawatts of SBSP. In the meantime, solar synchronous semi polar orbit has numerous advantages. Even far Northern countries can receive the beam during, and a few hours before, the evening peak demand period. With rare exceptions they won’t pay more than 4 cents per kilowatt hour for electricity at other times of day as their own generators are adequate, and not practical to shut down for a few hours. Other advantages are international companies and/or governments can share the start up costs, ship propulsion and the SPS is considerably closer than GEO but still in continuous sunlight. GEO satellite owners will be unhappy about megawatts, being transmitted near by.
    Economies of scale likely run out at less than 100 megawatts, making many SPS practical. This is because 100,000 volts dc at 100 amps = 10 megawatts. More volts or more amps creates rapidly rising costs in space, so logically we build many medium size SPS. The Sun delivers about 1300 watts per square meter, but following the numerous conversions, and losses perhaps only 130 watts per square meter is delivered to the grid. Thus one square kilometer of solar panel in space, puts 130,000,000 watts = 130,000 kilowatts = 130 megawatts on the grid. That may be a billion solar cells in series parallel. That many connections presents a reliability problem, especially for open cells which are likely to reach temperatures of thousands of degrees as the very high voltage arcs across the open circuit. Solutions, especially at one million volts, get very complicated, heavy and expensive.
    Almost a million laser diodes connected in series to use the million volts DC produce similar potential arcing which will damage nearby diodes.
    Laser diodes are superior as they can focus on to existing solar farms (or ships at sea) with dimensions as small as 60 meters by 100 meters = about 5000 square meters = one megawatt if the beam is 200 watts per square meter. Microwaves cannot produce that small a spot except from LEO = low earth orbit, which is shaded by Earth about 40 minutes out of each 100 minute orbit. Neil

  63. Raymond N. Cox said

    Hi Richard: I have not seen any details, but one possibility is SBSP at Earth moon L1, which for the moon is much like GEO stationary is for Earth. The SBSP would be in sunlight about 99% of the time and could beam energy to rectennas (solar sites if laser instead of microwaves) on about half of the side of the moon which is visable from Earth. Almost to the poles would be practical. The length of the beam would be about 56,000 kilometers compared to 36,000 kilometers for Earth GEO stationary orbit. This portion of the moon has two weeks of continious night, about 13 times per year. Neil

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