Solar Power Satellites: The Yes Case

Is now the time for major government funding of Space Solar Power?

The answer to this question is a resounding yes! And, may this answer reverberate throughout the scared halls of Congress and the parliaments of the free world. The time is now for the governments of the United States and the free world to commit themselves to the development of space based solar power in earth orbit or based on the lunar surface. This commitment has been long overdue and the United States of America and its allies have waited far too long to take a real and major concerted leadership role in the development of this vast untapped resource.

A commitment to space based solar power is vital to the long term national security, economic and environmental concerns of the United States and the world. America and the rest of the free world can no longer afford to remain the economic and political captives of nations and despotic regimes that neither share our democratic values nor love for individual human liberty. Yet our political adversaries control the strategic mineral and energy resources vital to our economic growth and prosperity. The United States and the free world can no longer allow themselves to remain bound by this status quo and must seek to change it.

America in particular must not relinquish nor endanger its leadership role as defender of the free world by making political and diplomatic compromises with these autocratic nations. And, neither should it allow itself to be forced to engage in reckless military actions that would compel other nations to question America’s real commitment to democratic values throughout the rest of the world in order to secure its hold on these resources.

The United States of America and the nations of the free world must commit themselves to a long term program of energy independence and give up our debilitating addiction to Mid-eastern oil and our dependency on strategic minerals located in the most politically unstable and volatile regions of the World.

For the whole of the preceding century and the first decade of this century we have been almost entirely reliant on fossil fuels. That was fine when fossil fuels were cheap and the full impact of their use on the environment was never fully understood. But, now it has become crystal clear that there are many hidden costs involved with our sole dependency on oil and other fossil fuels. These hidden costs are not just environmental but, as outlined above geopolitical and military in nature and effect the short and long term economic and political stability of the entire world.

The relatively low price of energy today is entirely dominated by the historically low cost of carbon based fossil fuels (e.g., petroleum, coal and natural gas).

There are several problems with existing energy delivery systems. They are subject to (among other problems)

political instability for various reasons in various locations — so that there are large hidden costs in maintaining military or other presence so as to continue supplies depletion (some well regarded estimates suggest that oil and gas reserves have been in net decline for some time and that price increases and supply decreases are inevitable) oil prices rose from around $20/bbl in the early 2000s to over $130/bbl in early 2008, despite no major disruptions in supply, suggesting to some industry observers (e.g., Matthew Simmons) that the days of cheap oil are over.

greenhouse pollution — fossil fuel combustion emits enormous quantities of carbon dioxide (CO2), a greenhouse gas, contributing to global warming and climate change.

Following the Kyoto Treaty, 141 countries introduced the first system of mandatory emissions control via carbon credits. The ultimate direction of such policies is to increase efficiency of fossil fuel use, perhaps to the point of elimination in some countries or even globally. But, the energy requirements of Third World or developing countries (e.g., China and India) are increasing steadily. Because of the net increase in demand, energy prices will continue to increase, though how fast and how high are less easily predicted.

And, neither nuclear energy (either fission or fusion) will prove to be a viable alternative.

Here are some of the problems presented by the use of nuclear fission energy production (a technology that has been with us for more than sixty years):

nuclear proliferation — not a problem with SPS
disposal and storage of radioactive waste — not a problem with SPS
preventing fissile material from being obtained by terrorists or their sponsors — not a problem with SPS
public perception of danger — problem with both SPS and nuclear power
consequences of major accident, e.g., Chernobyl — effectively zero with SPS, save on launch (during construction or for maintenance)
military and police cost of protecting the public and loss of democratic freedoms — control of SPS would be a power/influence center, perhaps sufficient to translate into political power. However, this has not yet happened in the developed world with nuclear power.
installation delays. These have been notoriously long with nuclear power plants (at least in the US), and may be reduced with SPS. With sufficient commitment from SPS backers, the difference may be substantial.

On balance, SPS avoids nearly all of the problems with current nuclear power schemes, and does not have larger problems in any respect, although public perception of microwave power transfer (ie, in the beams produced by an SPS and received on Earth) dangers could become an issue.

Energy via nuclear fusion also has its share of problems. It is still a technology yet to be realised. Despite more than fifty years or research effort we have yet to achieve a controlled nuclear fusion reaction that yields more energy than went into producing the reaction in the first place.

Nuclear fusion is a process used in stars, thermonuclear bombs (e.g., the H-bomb), and in a very small way some laboratory experiments. Projected nuclear fusion power plants would not be explosive, and will likely be inherently failsafe as the conditions for fusion on Earth are extremely hard to maintain and the reaction will promptly stop if any of them is changed (eg, via component or control system maladjustment or failure). However, sustained nuclear fusion generators have only just been demonstrated experimentally, despite extensive research over a period of several decades (since approximately 1952). There is still no credible estimate of how long it will be before a nuclear fusion reactor could become commercially possible; fusion research continues on a significant scale, including an internationally supported large scale project — the ITER facility currently under construction has been funded at about €10 billion[60]. There has been much criticism of the value of continued funding of fusion research given the continued failure to produce even small amount of net power in any of the varied attempted schemes.[61]. Nevertheless, proponents have successfully argued in favor of ITER funding.

In our quest to achieve controlled nuclear fusion on earth (a pursuit I still think is worthy of more research and funding) we must not overlook that we have a ready source of clean plentiful nuclear fusion energy shinning overhead in our skies. The technology to utilise this vast source of energy demands no major breakthroughs in physics or engineering and is already in our grasp. And, we have been using solar power in space for decades almost since the dawn of the space age.

In contrast, SPS does not require any fundamental engineering breakthroughs, has already been extensively reviewed from an engineering feasibility perspective over some decades, and needs only incremental improvements of existing technology to be deployable. Despite these advantages, SPS has received minimal research funding to date in comparison.

What about other green renewables, in particular terrestrial or ground based solar power, wind power, geothermal, hydro power, et cetera?

Let us begin by comparing space based solar power with ground based solar power of similar capacity:

Per-kilowatt-hour photovoltaic costs have been in exponential decline for decades, with a 20-fold decrease from 1975 to 2001.

An SPS requires much less ground area per kilowatt (approx 1/8th to 1/100), depending on the location of the ground-based system, time of year, weather conditions and other factors.
A ground-based system intercepts an absolute maximum of only one third of the solar energy an array of equal size could intercept in space, since no power is generated at night and less light strikes the panels when the Sun is low in the sky or weather interferes.
The rectenna of an SPS would have a smaller footprint than the equivalent solar array, as it receives more power per unit area. A solar panel in the contiguous United States on average delivers 19 to 56 W/m² . An SPS rectenna would deliver about 23mW/cm² (230 W/m²)[36] continuously, hence the size of rectenna required per collected watt would be about 8.2% to 24% that of a terrestrial solar panel.
An SPS rectenna can be made transparent and thus would not impact land use. For example, crops could be grown beneath it.

An SPS provides continuous power, whilst a ground-based system would require some form of energy storage if it were to provide power at night.
Ground-based systems are more vulnerable to terrorist attack.
A ground based system requires continual maintenance. Wear and tear on orbital installations can be reduced by care in design and fabrication.
An SPS can deliver power where needed by redirecting its microwave beam, whilst a ground-based system must rely on the grid to distribute its power.

SPS could be used to produce chemical fuels for transportation and storage, as in the proposed hydrogen economy. Or they could both be used to run an energy storage scheme (such as pumping water uphill at a hydropower generation station).

An average of approximately 0.1 and 0.2 kW/m² of solar energy can be received from the Sun on the Earth’s surface. Solar energy (total global insolation) striking the earth’s surface consists of 2 components, direct and diffuse (diffuse light may be further subdivided into several other categories). Due to influences of the atmosphere (reflection, absorption and scattering), including man made gases and particulates only 10% to 13% of the total incident energy approaching the earth’s cross sectional area from the sun is available on earth.

Extraterrestrial solar power is that collected outside of the earth’s atmosphere. Besides man-made satellites in GSO, locations for this conversion may be sun-synchronous (near-polar, always facing the Sun) orbit, space probes, the moon, or other planets.[ There is little loss of microwave energy passing through the Earth’s atmosphere and there is no contribution to the global warming problem by the addition of CO2 during the production stage. In addition, the orbit of rotation can be selected such that sunlight is received by the satellite ~96% of the time. In near Earth space the average ~1 to 2 kW/m² of energy that can be collected is approximately ten times as much the solar energy available on earth. (Earth’s orbit causes varying extraterrestrial S flux between approximately 1329 and 1421 W/m². 1370 W/m² is the solar constant, i.e., mean flux perpendicular with the solar beam in outer space, at the mean distance from the Earth to the Sun. Unaffected by atmospheric gases, particulate matter and cloud cover, photovoltaic arrays in a geostationary Earth orbit (at an altitude of 22,300 miles) would receive, on average, eight times as much sunlight as they would on Earth’s surface. In addition, they would be unaffected by the Earth’s day-night cycle.

Other renewable energy sources while suitable for small scale production of energy will never completely meet the exponential demands of a growing global economy.

Most renewable energy sources (for example, tidal energy, hydro-electric, geothermal, ethanol), have the capacity to supply only a fraction of the global energy requirement, now or in the foreseeable future. For most, the limitation is geography as there simply are very few sites in the world where generating systems can be built, and for hydro-electric projects in particular, there are few sites still open. For 2005, in the US, hydro-electric power accounted for 6.5% of electricity generation, and other renewables 2.3%. The U.S. Govt. Energy Information Administration projects that in 2030 hydro-power will decline to 3.4% and other renewables will increase to 2.9%.

The Road Ahead

The United States must exercise its leadership role in concert with its allies to meet the social, political and environmental challenges that face and vex us in our present epoch. We must seek to feed the hungry multitude, shelter the homeless, cure the sick and pledge ourselves to ending global poverty.

America and the nations of the free world must also commit themselves to the long term goal of maintaining the health and vitality of this planet in all its realms – land, air and sea. All of which are integral to the long term habitability of our world. And also initiate a long term program of planetary defence from the possibility of cometary and asteroidal impact.

In order to meet these challenges we are in desperate need of renewable and plentiful energy. That energy lies in out in space and can only come from the Sun.

Our space programs must reflect the geopolitical realities of our age. Only a space program with the goals of defending our planet and developing the energy and mineral resources of cis lunar space is economical sustainable and politically justifiable given the present economic and political realities of the present age.

A crucial first step in meeting these objectives is for America and the world to embark and commit itself to a long term space program with the clear objective of developing the mineral and energy resources of outer space. We the nations of the free world must thus commit ourselves to a phased approach to the development of space based solar power in the near term. We can no longer wait and procrastinate, the problems we face as a planet are much too urgent.

In the short term America and the free world must look at our present major technological asset currently orbiting the earth – the International Space Station (ISS). The solar arrays are the most prominent feature of the International Space Station — and arguably the most important! Within the next decade it would be a crucial first test and proof of concept to perform an experiment where part of the energy generated by the ISS’s solar arrays are transmitted to earth and a ground receiving station and converted to electricity.

“The Pentagon’s National Security Space Office (NSSO) issued a report on October 10th, 2007 that states they intend to collect solar energy from space to help the United States’ ongoing relationship with the Middle East and the battle for oil. Solar power is a clean source of energy that has no effect on the environment. The International Space Station is most likely to be the first test ground for this new idea, even though it is in a low-earth orbit”.

After this initial proof of concept it is vital that we place in geosynchronous orbit a solar power test satellite of the megawatt or gigawatt generating capacity to test the efficiency of new generations of photovoltaic cells and power beaming modalities (such as laser or microwave) to ground receiving stations in a variety of weather and climatic conditions. It is during this testing phase that we can fully assess possible environmental impacts of beaming energy from space and work out countermeasures to mitigate their effects.

In 1999 NASA’s Space Solar Power Exploratory Research and Technology program (SERT) was initiated for the following purpose:

Perform design studies of selected flight demonstration concepts;
Evaluate studies of the general feasibility, design, and requirements.
Create conceptual designs of subsystems that make use of advanced SSP technologies to benefit future space or terrestrial applications.
Formulate a preliminary plan of action for the U.S. (working with international partners) to undertake an aggressive technology initiative.
Construct technology development and demonstration roadmaps for critical Space Solar Power (SSP) elements.
It was to develop a solar power satellite (SPS) concept for a future gigawatt space power systems to provide electrical power by converting the Sun’s energy and beaming it to the Earth’s surface. It was also to provide a developmental path to solutions for current space power architectures. Subject to studies it proposed an inflatable photovoltaic gossamer structure with concentrator lenses or solar dynamic engines to convert solar flux into electricity. Collection systems were assumed to be in sun-synchronous orbit.

When the United States returns to the moon, within the next decade, the testing of the possibility of the large scale generation of solar power on the lunar surface and transmitting this energy to earth should be one of the most prominent experiments on the applied science agenda.

Only then can we decide whether to base our solar collecting assets on the moon or earth orbit and determine the most cost effective approach to harness this vast untapped energy resource.

The role of democratic government is to lead and to set the agenda of meeting the needs and safe guarding the quality of life and security of its citizens. So let me reiterate my resounding yes to the question – Is now the time for major government funding of Space Solar Power? Because in developing this renewable and vast resource of energy we will be ensuring the long term security and prosperity of our citizens for generations to come. With the added bonus of creating a new industry that will power the free market of the future.

Author’s note: I would like to acknowledge the kind help of Mr. Charles Radley, a major advocate of Space Solar Power, for reviewing a preprint of this article. Any short comings in this article are of course entirely my own.

I would also like to refer the novice reader to the following excellent reference articles found on Wikipedia:

Space Solar Power

Solar Power Satellite

The portions of my article that appear in italics are direct quotes from these two excellent articles.

I would also like to refer all my readers to Ben Bova’s excellent letter to the President entitled “An Energy Fix Written in the Stars” concerning SSP that appear in the Washington Post Sunday, October 12, 2008.

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6 Responses to “Solar Power Satellites: The Yes Case”


  1. 1 Rod Adams January 20, 2009 at 9:28 am

    Alex – all in all, a very complex article that obscures reality. Based on a January 2009 presentation by one of the vendors pushing this idea into the minds of gullible people, the estimated cost of a first unit would be in the neighborhood of $240 per installed watt or two orders of magnitude higher than a fission based alternative.It is also clear, based on the presentation that the room for growth in such a system is severely limited by the available parking spaces in geosynchronous orbit, by the incredible quantity of mass that would need to be lifted to that high orbit, and by numerous other “potential show stoppers” for which there is no available technical solution.When it comes to the worries about fission that you listed, it appears that you have been bamboozled by the same pro fossil fuel group that has consistently opposed the development of nuclear fission. Despite all opposition, however, fission has a remarkable 50 year history of providing clean, emission free power at a reasonable cost, especially if there are few outsiders imposing as much delay and cost as possible on the construction process.Rocket technology is actually more destabilizing that fission technology – who cares if someone has a weapon if they cannot deliver it. If, however, the technology to build massive rockets for your space solar power is more widely available…

  2. 2 M. Simon January 20, 2009 at 2:47 pm

    Rockets based on this technology:Easy Low Cost No Radiation FusionRick Nebel Updates The Latest NewsWould make SPS affordable. They would also make it unnecessary.

  3. 3 spacelobbyist January 20, 2009 at 6:31 pm

    Space solar power is the only source of power with the potential to save the planet from the coming energy crisis, while not exacerbating global warming. It is a necessity, not a choice, and the government needs to start helping it move along.

  4. 4 Dan Wylie-Sears January 22, 2009 at 5:17 pm

    Eventually we will need either fusion or SPS. In the near term, however, terrestrial renewables are more than sufficient. The only argument given against them is that they’re currently a very small fraction of the energy we use, but if that were the criterion then SPS would be hopeless since it’s at zero.This page lists the capacity of solar as 340 TW, wind over land as 47 TW, and current demand as 14 TW.

  5. 5 Solar Products May 18, 2009 at 7:46 am

    Thanks for this useful post…


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