The deployment of space platforms that capture sunlight, generate electricity, and transmit electrical power to Earth has been explored by government departments and universities globally for decades. It could be a way to offer global energy and security benefits – including the prospect of short-circuiting future resource wars between increasingly energy-starved nations.
Imagine providing the earth or a moon base with harnessed solar power, or traveling in space without returning to earth for fuel. That’s the idea behind space-based solar power generators such as this SunTower. Depending upon size, two small panels on a tall tower could power a communications satellite, four panels might power a robotic interplanetary probe, six a manned spacecraft, while 20 panels might supply energy down to the earth or to a lunar base. Image Credit: NASA
A proposal is being vetted by U.S. military space strategists that 10 percent of the U.S. baseload of energy by 2050, perhaps sooner, could be produced by space-based solar power (SBSP).
A mix of advocates, technologists, and scientists, as well as legal and policy experts, took part in Space-Based Solar Power – Charting a Course for Sustainable Energy, a meeting held on September 6-7, 2008. This was sponsored by the United States Air Force Academy's Eisenhower Center for Space and Defense Studies and the Pentagon's National Security Space Office.
Energy from Space
"I truly believe that space-based solar power will become the first sellable, tradable commodity that's delivered by space that everybody on the planet can have part of," said Colonel (Select) Michael Smith, Chief, Future Concepts in the National Security Space Office and director of the SBSP study.
To bolster such a vision, establishing a partnership of government, commercial, and international entities is under discussion, he added, to work on infrastructure development that ultimately culminates in the fielding of space-based solar power.
The U.S. Department of Defense has an "absolute urgent need for energy," Smith said, underscoring the concern that major powers around the world – not just the United States – could end up in a major war of attrition in the 21st Century. "We've got to make sure that we alleviate the energy concerns around the globe," he said.
Energy may well be the first tangible commodity returned from space. Geopolitics in general is going to be a large issue. I don't think there's any question that energy is going to be one of the key next issues, along with water ... that's going to be the competition we're going to fight.
Joseph Rouge, Associate Director, National Security Space Office
Rouge said that moving out on the proposed SBSP effort would be the largest space venture yet.
"Look to us to help you develop the technologies and developing a lot of the other infrastructure," Rouge advised, seeing SBSP, for instance, as helping to spur a significant reduction in the cost of routine access to space for the U.S. and its allies.
Space-Based Solar Power: Trends of Concern
There is a compelling argument of synergy between energy security, space security, and national security, observed Col. Michael Hornitschek, Co-Chair of the National Security Space Office Architecture Study on Space-Based Solar Power.
Hornitschek flagged "trends of concern" in dealing with the worldwide energy challenge, citing global population and escalating energy demands, as well as the portent of climate change. He also referred to U.S. loss in global market share and leadership, in addition to declines in research and development investments and a skilled workforce.
Although space-based solar power has been studied since the 1970s – by the Department of Energy, NASA, the European Space Agency, as well as the Japan Aerospace Exploration Agency – Hornitschek said that the idea has generally "fallen between the cracks" because no organization is responsible for both space programs and energy security.
Over the last few decades, the march of technology useful to SBSP has been significant, said Neville Marzwell, Manager of Advanced Concepts and Technology Innovation at the Jet Propulsion Laboratory in Pasadena, California.
"We have made tremendous progress in technology from 1977 to 2007," Marzwell reported. He pointed to advances in micro- and nano-electronics, lightweight inflatable composite structures, ultra-small power management devices, as well as laboratory demonstration of photovoltaic arrays that are close to 68 percent conversion efficiency.
Still, there's work to be done, Marzwell emphasized, specifically in wireless power beaming. By modularizing SBSP platforms, the work can start small and foster batch production to keep the price per unit costs down while evolving a bigger energy market, he said.
Space-Based Solar Power: Science and Technology Challenges
Overall, pushing forward on SBSP "is a complex problem and one that lends itself to a wide variety of competing solutions," said John Mankins, President of Artemis Innovation Management Solutions, LLC, in Ashburn, Virginia.
There's a whole range of science and technology challenges to be pursued. New knowledge and new systems concepts are needed in order to enable space-based solar power. But there does not appear, at least at present, that there are any fundamental physical barriers.
John Mankins, President of Artemis Innovation Management Solutions, LLC, Ashburn, Virginia
Peter Teets, Distinguished Chair of the Eisenhower Center for Space and Defense Studies, said that SBSP must be economically viable with those economics probably not there today. "But if we can find a way with continued technology development ... and smart moves in terms of development cycles to bring clean energy from space to the earth, it's a home run kind of situation," he told attendees of the meeting.
"It's a noble effort," Teets told Space News. There remain uncertainties in SBSP, including closure on a business case for the idea, he added.
I think the Air Force has a legitimate stake in starting it. But the scale of this project is going to be enormous. This could create a new agency ... who knows? It's going to take the President and a lot of political will to go forward with this.
Peter Teets, Distinguished Chair of the Eisenhower Center for Space and Defense Studies
Space-Based Solar Power: Demonstrations are Vital
As the current director of the SBSP study for the National Security Space Office, Smith said that demonstrations of beamed energy from space – utilizing both breadboard lab tests and by using space assets – are vital. One possibility is to extrapolate meaningful lessons from signal transmissions by already orbiting communication satellites, he said, be they U.S. assets or experiments done with partners elsewhere around the world.
An orbiting SBSP demonstration spacecraft must be a useful tool, Smith added, to deliver energy while retiring science questions and identifying risk areas for next phase SBSP development. Conceptually, a locale to receive test broadcasts of beamed energy from space could be Creech Air Force Base in Indian Springs, Nevada, he noted.
Mankins told Space News that the International Space Station could also be used to conduct a whole range of in-space SBSP-related experiments on relevant component technologies or subsystem technologies. "The space station is perfect for that," he said, perhaps making use of Japan's still-to-be-lofted experiment module, Kibo, and its Exposed Facility located outside of the pressurized module.
Recent Developments in Space-Based Solar Power
Since the US Pentagon’s 2007 report, space-based solar power has somewhat stalled, at least in the US. A workshop held by the Massachusetts Institute of Technology (MIT) in 2007 and the establishment of the Space Solar Power Initiative by Caltech and Northrop Grumman Corporation in 2015 reflect industry and academic interest in the concept, however, the US Department of Defence has been largely quiet on the matter.
In 2016, however, the Department of Defence, Department of State and Northrop issued a proposal arguing the US must lead the way in space-based solar power. After this, a private group named Citizens for Space-Based Solar Power has been leading petitions to the White House for investment in the concept and proposals put forward.
Outside of the US, China, India, and Japan have all been involved in trials of various components of a space-based solar power system. The race is on.
This article was updated on 24th February, 2020.