Projecting power: The security implications of space-based solar power

Abstract

Space-based solar power is a system for delivering a potentially limitless supply of clean energy to a world desperately searching for alternatives to fossil fuels. However, while the system offers the promise of unlimited, “green” electrical power, it also has immense potential as a geopolitical tool. For example, this new power source could be used to support troops, rebels, or international aid workers virtually anywhere in the world. Space solar power research has recently experienced something of a renaissance, but so far there has been very little discussion about the security implications of this potentially transformative technology. While it will be at least a decade, if not two, before the infrastructure for deploying a full-scale system exists, developing policies and norms—international and national—capable of effectively engaging such a technically and politically complex issue can itself require years of work. Policy makers and political scientists should begin debating the security impacts of space-based solar power now, lest technological development outpace the ability of governments and international institutions to meaningfully assimilate it.

Increasing oil prices and environmental conscientiousness have generated a commensurate spike in interest in renewable energy sources. Most technologies, however, are ill-suited to providing large-scale, base-load power. Solar, wind, hydroelectric, and geothermal power all rely on specific environmental or geographic conditions that are intermittent or uncommon in nature. Furthermore, the places where these conditions do occur are often far from the population centers where power is needed most. Of the mature renewable energy systems, solar is the most widely applicable, because the sun, to a greater or lesser extent, shines everywhere. But even photovoltaic solar power systems cannot provide universal base-load power. Subject to the vagaries of weather, season, and the diurnal cycle, photovoltaic systems are typically regarded as a supplementary system, at best.

There is one place, however, where the power of the sun remains unattenuated by the messy conditions on the surface and uninterrupted by the day–night cycle. The Earth’s orbit receives a solar flux of approximately 1,400 watts per square meter, and a space-based solar power system would take full advantage of this energy source. By the time the sun’s rays reach the planet’s surface, the solar flux is reduced, on average, to a quarter of this value (National Security Space Office [NSSO], 2007).

The centerpiece of a fully developed space solar power system would be a huge satellite, with mirrors or collecting surfaces measured in square kilometers, located in geostationary orbit—approximately 22,236 miles (or 35,786 kilometers) directly above the equator, where satellites travel at the same speed as the Earth’s rotation and thus appear to be motionless. Using photovoltaic panels, this satellite would collect incident solar radiation to generate electricity and then use onboard equipment to convert the power thus generated into an electromagnetic beam. Most proposed architectures call for either an infrared or microwave beam (Seffers, 2010). This beam would be aimed at a receiver on the ground, where it would be converted back into usable electricity and then fed into the grid for consumption. The beam would be dispersed over a large receiving array, so birds and aircraft would be able to safely fly through it (Lunau, 2010).

Not only would power delivered in this way generate no greenhouse gases, but it would be consistent, reliable, and scalable. Most of all, however, such a system would be flexible. A space solar power system with only two or three satellites would be capable of directing gigawatts of power to virtually any point on the globe.

By nature of its basic characteristics, the system has implications that extend far beyond national energy and industrial policy. Its ability, in principle, to deliver strategically significant levels of electrical power almost anywhere in the world has important international security ramifications. There are many ways that space-based solar power could be used in novel security-oriented modes. From supporting friendly troops and providing disaster relief in the field, to propping up rogue regimes, the technology has the potential to offer those nations that develop it a powerful and flexible tool with fundamentally new, even transformative, applications.

An apt example is the recent civil war in Libya. If one or more NATO powers had had an operational space-based power system, they could have delivered sufficient energy for the rebels to maintain a significantly more complex infrastructure, even as the old regime’s infrastructure was reduced to rubble by air strikes and general fighting. Despite the powerful new security capabilities that a space solar power system represents, the technology has received little attention in the academic literature outside of scientific and engineering circles.

Three phases of interest

Fantastic as the concept may seem, a space solar power system is not science fiction. In recent years especially, it has gained currency with several governments, notably China and Japan, and a number of new companies in the United States and abroad are dedicated to commercializing the concept. Furthermore, its constituent technologies are, overall, quite mature.

The idea has seen sporadic periods of official interest in the United States since it was first articulated. Peter Glaser is generally credited with first promulgating the concept of space-based solar power in 1968 (Lunau, 2010) and was granted a patent for the idea in 1973. ¹ Since that time, space solar power research in the United States has remained more or less at a low simmer. NASA and the Energy Department have collectively spent more than $80 million over the past three decades on efforts that can be characterized as having three distinct stages.

The first major effort began in the 1970s, when NASA and Energy jointly studied the scientific feasibility of the concept and proposed a reference 5-gigawatt design. However, the technology of that era did not make such a proposal economically feasible. During the second phase of the space solar system’s development, from 1995 to 1997, NASA initiated a “fresh look” study to reexamine the concept in light of newer technology capabilities (NSSO, 2007: 1).

The third phase in the United States began in 2007, when the Pentagon’s National Security Space Office (NSSO) ² published a report titled “Space-Based Solar Power as an Opportunity for Strategic Security.” Although media outlets were excited about the concept, there has been little intimation that the US government has any real interest in it. In comparison, during the circa-1997 renaissance, space-based solar power was championed not only by NASA (as opposed to a relatively obscure Pentagon office), but also by a member of Congress. In 1997, Rep. Dave Weldon, a Florida Republican, ³ urged Congress to have a public debate about space-based solar power and prevailed upon NASA to take a more “serious look” at the concept (Breen, 1997).

It is only recently, however, that anything beyond very preliminary technical or cost assessments has been produced. In the last few years, firms such as Solaren in the United States and Space Energy of Switzerland have begun taking a serious look at what it might take to move the technology beyond the concept stage.

Unlike more speculative energy technologies like nuclear fusion, space solar power requires no fundamental breakthroughs in science or engineering. The complete architecture of the system is well-understood. One executive with Solaren noted: “We don’t need to invent solar cells, antennas, or radio-frequency transmission technologies. All that’s been done. We just need to do it on a bigger scale” (Seffers, 2010).

Of course, it is precisely the scale of the system that is most problematic. Extending the relevant technologies physically to the kilometer scale, and energetically to the gigawatt range, will certainly present challenges—as will building, assembling, and maintaining the component pieces of the final system. The greatest hurdle is getting the system into orbit. In order for space-based solar power to be competitive with other energy technologies, it must be able to deliver power with a final cost on the order of $0.10 per kilowatt-hour. Given current launch costs, this is a rather dubious proposition. The Japan Aerospace Exploration Agency (JAXA) is generally quite sanguine about the prospects of the system. Even so, one JAXA official remarked that its plans to develop space solar power are feasible only if “the current space transportation cost is assumed to be reduced by a factor of 50 to 100 using reusable launch vehicles expected in the future” (Hsu, 2011). The Pentagon’s report further concluded that deploying a cost-effective system would require not only inexpensive space access, but also significant on-orbit infrastructure (NSSO, 2007).

Three investments in space-based solar power

The technological and infrastructural issues inherent to deploying a solar power system in space, while certainly daunting, have not stopped several private firms from taking an explicit and substantive interest in developing such a system. While these companies are independently pursuing the goal of commercializing the system, their activities are largely complementary. One firm, Solaren, signed a deal with Pacific Gas & Electric to deliver power from space by 2016 (Parsons, 2010). While Solaren is somewhat tight-lipped about how they plan to meet their contract obligations, an executive with the company stated that the system would consist of a constellation of satellites smaller than those called for in the Pentagon’s baseline design, lofted by “four or five” heavy-lifter launches (Boyle, 2009). Whether the optimistic deadline can be met remains to be seen, but the mere fact of the deal’s existence demonstrates that the power industry considers the concept a feasible investment.

Meanwhile, the PowerSat Corporation is more focused on developing the technological aspects of the system. Based near Seattle, the company holds a growing patent portfolio that includes technologies for power transmission and on-orbit station-keeping (PowerSat Corporation, 2010).

The Space Energy firm is approaching the matter from yet another direction, focusing primarily on raising awareness of the technology and expounding upon its various benefits, especially in comparison with traditional energy sources such as nuclear and coal. Space Energy has not only given public lectures on the technology, but has worked with the Japanese and Chinese governments to develop their own concepts for space-based solar power (Space Energy, 2010).

As Space Energy’s activities show, the current interest in such systems transcends the private sphere. Japan has made the development of space-based solar power a national priority. A partnership is now in place between JAXA and industrial giant Mitsubishi to lay the groundwork for a megawatt-class demonstration system within a decade or so and a gigawatt-class satellite within 20 years (Cyranoski, 2009). Japan’s 2009 National Space Plan called for a program to “lead the world in space-based solar power” (Cyranoski, 2009).

Echoing this sentiment, Wang Xiji, a senior official at the China Academy of Sciences argued, “Whoever takes the lead in the development and utilization of clean and renewable energy and the space and aviation industry will be the world leader” (Want China Times, 2011). One Chinese plan for development calls for a variety of milestones over the coming decades—including demonstrating power transmission and on-orbit construction techniques—culminating in a commercial, gigawatt-class station going online in about 2040 (Gao et al., 2010). While the Chinese plans for space solar power are primarily couched in terms of energy security, the language regarding international leadership suggests that Chinese planners have considered the strategic importance of the system.

Given the lack of attention to space-based solar power in the policy and political science literature in the United States, it is perhaps unsurprising that Washington has shown barely a glimmer of interest in the concept, despite the enthusiasm in Tokyo and Beijing. But a failure to invest in the technology could ultimately prove shortsighted and strategically disadvantageous.

Security challenges

There are two main types of security challenges posed by space solar power: threats to the system itself and potential operational modes of the technology that generate security concerns. Each of these two categories is composed of several sub-issues that must be substantively addressed by policy makers and political scientists if there is to be effective debate on space-based solar power’s geopolitical ramifications.

Much of space technology is inherently dual-use. The same GPS satellites that provide a motorist with directions to the nearest gas station also provide terminal guidance for precision munitions—and the rockets that loft those satellites are in many ways indistinguishable from long-range missiles capable of carrying destructive payloads to a terrestrial target. The literature and international treaty corpus is rife with discussions and agreements regarding the best practices for limiting the proliferation and misuse of such technologies. Space-based solar power is no different insofar as its dual-use nature is concerned, but is distinct in that the security implications of the technology have not received more attention.

A space solar power system would represent a serious capital investment and strategic asset for the nation that develops it. The destruction or disruption of a full-scale system would not only constitute the loss of a major piece of infrastructure, but could leave many thousands of people without power and the government without access to a powerful asset. Such disruption could plausibly have both natural and human-made origins.

Service interruptions

The most basic security problem is that of service interruption caused by interference with either the collection array or the beam that delivers power from space. Placing a power satellite in geostationary orbit means that it will have nearly constant direct exposure to the sun. Occasional, brief blackout periods may occur due to eclipses. While such events may be unavoidable, orbital mechanics are predictable enough that such ephemeral interruptions could be planned for and mitigated by various means (PowerSat Corporation, 2010). Weather and atmospheric attenuation is likewise much less of a concern than it is for land-based solar power. For a space-based solar power beam transmitted at 2.48 or 5.8 gigahertz, atmospheric transparency is very high; clouds and storms would not prevent most of the transmitted power from reaching the ground station (NSSO, 2007). Thus, natural sources of service interruption due to beam interference should be rare and easily predicted, and their impact ameliorated when they do occur.

Intentional service interruptions are another concern. A space-based solar power satellite has much in common with communications and GPS satellites, which also transmit radio-frequency beams to Earth. An adversary could jam these types of satellites and cause them to malfunction (Economist, 2011), but a space-based solar power system should be insulated from jamming for two reasons: First, most communications and navigation satellites operate at very low power, so a jamming signal need not be very powerful in order to drown out the information being transmitted. A full-scale solar power system, on the other hand, has a beam power that is rated in gigawatts; even if jamming such a beam were possible in theory, it would be prohibitive in practice. Secondly, most jamming techniques rely on making signals unintelligible by transmitting “noise” that overwhelms the information-carrying signal, but a space-based solar power satellite transmits raw energy rather than noise-sensitive information. It should be noted, however, that it may be possible to jam the telemetry links between a power satellite and ground controllers, potentially leading to a loss of command authority over the system.

Physical disruptions

Solar power satellites may also be degraded by physical disruption. Again, such damage could occur naturally or artificially. Collisions in space do occur. The primary source of such impacts is space debris. Orbital debris consists of everything from expended upper-stage rocket boosters to flecks of paint. At orbital velocities, even a collision with a small piece of such flotsam can be catastrophic. Collisions can also occur between intact spacecraft. In early 2009, the Russian Cosmos 2251 satellite accidentally struck and destroyed a functional Iridium network satellite (Ianotta and Malik, 2009). The specter of space debris and direct collisions between spacecraft, however, is largely an issue for lower orbits. The majority of such detritus orbits well below the altitude of geostationary orbit, where a space-based solar power system is likely to be built (NASA, 2009).

The high altitude also makes the system less susceptible to intentional destruction. Anti-satellite weapons are an established and mature technology; both China and the United States have demonstrated their ability to use them in the recent past (Koplow, 2009). However, the Chinese and US anti-satellite tests engaged spacecraft at altitudes well below 1,000 kilometers (Gugliotta, 2008). Delivering payloads to geostationary orbit is more challenging and requires large rockets. While a nation such as China or the United States could, in principle, conduct anti-satellite strikes in geostationary orbit, neither has demonstrated this capability nor seems eager to do so. Because of the difficulty of reaching such high altitudes, it is very unlikely that a rogue state or terrorist element would have the means to physically disrupt a power satellite.

The altitude that largely insulates geostationary orbit satellites from anti-satellite weapons poses its own issues. Despite the large number of satellites and pieces of debris located there, low orbit is still very sparsely populated, and the distances between spacecraft are commensurately large. By contrast, geostationary orbit is a narrow, crowded band. Some parts of the orbit—especially those over Europe, North America, and East Asia—can be positively claustrophobic. It is thus possible that a “sabotage” satellite or “space mine” could be maneuvered into close proximity to a space-based solar power satellite under somewhat plausible pretenses. So important is geostationary orbit, however, that the position and movement of satellites there are tracked assiduously. An attack, and the identity of the attacker, would likely be painfully obvious after the fact if not before.

New capabilities

Besides threats to the satellite itself, how such a system is used also has important security ramifications. In its 2007 report, which appears to be the only US government document dealing with the security aspects of space-based solar power, the Pentagon identified more than a dozen potential implications of the system. Key among these was the ability to deliver reliable and constant power to forward-deployed troops potentially anywhere in the world by redirecting the satellite’s beam to another receiving station. Such a capability could dramatically reduce the logistical burden of supporting armed forces, whose energy needs are now largely met by transporting large quantities of fossil fuels. This new capability also has the potential to reduce casualties, because there would be reduced need for supply convoys to traverse hostile territory (NSSO, 2007).

The technology is not inherently limited to supporting the troops of the country that develops it. While building and launching the satellite for such a system would be expensive and technically complex, the ground station that receives the power would be easier to engineer and construct. That means the space-based power system could be used to support troops of a friendly nation without ever risking a nation’s own forces, although the Pentagon report did not specifically mention this capability. It could also be used to support rebels or insurgents within the sovereign territory of another nation or to support a regime currently facing energy shortfalls due to internal or interstate warfare. In an extreme case, the system could be used to support a foreign state that is facing an energy embargo or blockade. Because a space-based solar power beam cannot be jammed, interdicting such intervention might necessitate direct action against either the satellite itself or the receiving ground station, either of which could dramatically broaden the scope of a conflict.

The ability of the system to direct power on short notice to most points on the globe also has significance for international aid and disaster relief. In the wake of a natural or humanitarian disaster, power from space could be used to keep hospitals and refugee camps operational, as well as providing electricity for water desalination and other critical but energy-intensive processes. Operating in this mode, space-based solar power could become a powerful tool of diplomacy rather than one of force projection in the traditional sense.

The work ahead

While space-based solar power offers the promise of abundant, clean energy, the technology can be used to project power in more than one sense. The unique characteristics of the system mean that it has profound international security implications, yet these issues remain substantially unaddressed. Not only is the concept of the system largely absent from the policy and political science literature, but it does not fall under the effective auspices of international law. The Outer Space Treaty of 1967 is silent on most aspects of the militarization of space aside from the use and deployment of weapons of mass destruction, and even in this respect its scope is ill-defined (UN Office for Outer Space Affairs, 1967). While there have been some attempts in recent years to begin discussion about a treaty banning conventional weapons in space (often spearheaded by China), even these notional efforts only address actual weapons, not power systems (CD 1839, 2008).

The individual component technologies of the space solar power system are mature, but the space infrastructure required to construct and maintain such a system will take years, if not decades, to develop. In practical terms, this is not as long as it sounds. The establishment of international agreements, norms, or institutions capable of handling an issue as complex and potentially important as space-based solar power is itself often the work of decades. There are a number of ways in which the international community could address concerns about the system, from non-binding principles of conduct to more formalized treaties, but such agreements cannot be expected to emerge spontaneously. Debate on the issue should begin now, lest development of this potentially transformative technology outpace the international community’s ability to effectively assimilate it.