The watershed event in space solar power has
The U.S. National Space Security Office issued a preliminary assessment Oct. 10 titled, “Space Based Solar Power as an Opportunity for Strategic Security.”
The space-based solar power (SBSP) concept has been kicked
�around since Peter Glaser first published a description in 1968: using large orbiting satellites to convert solar energy in space to electricity and beaming the power to Earth for terrestrial use. It drew some interest in the ensuing decade not because of the current hysteria about global warming, but because
�oil soared to the unbelievably high price of $12 per barrel. The U.S. Department of Energy and NASA conducted an extensive study of a so-called “reference design” in 1978, and concluded that while technically feasible, the system’s economics were nowhere near practical. Their conclusion, to shelve the idea for a decade or more to see how the technology and the market would develop, made very good sense at the time.
Despite the clearly infeasible economics of the SBSP concept – not to mention
the high “giggle factor” associated with launching dozens of thousand-ton spacecraft to
�– the fascinating long-term prospects of delivering the world from dependence on (and the environmental impacts of) fossil fuels has stirred up considerable interest.
In-depth assessments of the Department of Energy-
NASA study were conducted early in the 1980s by the U.S. Congress’s Office of Technology Assessment, the National Academies’ National Research Council
�and the American Institute of Aeronautics and Astronautics (AIAA). Three bills were written in Congress,
and at least three more were drafted,
�proposing various SBSP programs and goals. Controversy raged, not only over the obvious concerns – orders-of-magnitude growth in space operations and doubts about long-term economics – but also over a host of political, societal, environmental, military
�and international regulatory issues.
However, despite considerable interest in the concept by the Japanese, the idea languished with little attention for
more than a decade.
Then in 1995 NASA conducted a “fresh look” study
to explore the effects of technological progress and changes in market dynamics since the 1979 report. NASA followed up
with a series of comprehensive Concept Development and Evaluation studies that documented major advances in technology, market opportunities
�and dual-use benefits to both civil and military space programs. Several AIAA assessments confirmed the significant progress that had been made. But in 2001 NASA decided it had more important fish to fry, and closed down all research and evaluation of SBSP
For nearly a decade
not much happened. Then in March of this year, the NSSO assessment was initiated.
Further interest was created by an August
table sponsored by Washington’s George C. Marshall Institute and a September
workshop at the U.S. Air Force Academy, Colorado Springs, Colo., at which the then-ongoing NSSO study was discussed.
The new-found, unequivocal interest in SBSP by the military
could be the turning point for its
. A number of published reports in the trade media
have documented the salient points of this new sector’s interest.
The most recent example,
the commentary by James Vedda
[Space News, Oct.
�29, page 19]
�SBSP as one of the substantial contributions that would make space much more important to mankind than would sending humans to Mars.
Although the NSSO report clearly states that the Pentagon
�would not be the appropriate agency to fund the development of SBSP, it does state
�that the military would be quite interested in serving as an “anchor customer.” Electric power to support advanced bases in Iraq and other far-flung military posts, including the logistics of fuel supply,
now is costing the
Forces well over $1 per kilowatt-hour
, versus the current price of $0.03-
$0.05 cited as the competitive barrier for commercial SBSP power. In the interest of national security, the report calls on the U.S. government to create a program that will reduce the technical and economic risk of developing a full-scale SBSP system, culminating in the funding of a demonstration powerplant in the 5-10 megawatt
range. The development of a space transportation system and the logistic technologies capable of delivering such a unit, in whole or in parts to be assembled in orbit, is cited by the NSSO as
key to future growth in both civil and military space activities
This is precisely what SBSP supporters have been advocating for years. Developments in solar photovoltaics; electric power management and distribution; laser power conversion, transmission
�and reconversion; lightweight structures (including inflatables, as demonstrated by Bigelow Aerospace’s Genesis modules currently in orbit); structural dynamics of very large spacecraft; robotic assembly; and high-efficiency orbit-transfer propulsion have moved these technologies very close to the point at which they soon could
be incorporated into an operational demonstration SBSP system. The principal technical barrier remains sufficiently low-cost, reliable transportation from Earth to low orbit, but a soundly supported SBSP development program could very well be the catalyst that solves this perennial “chicken-and-egg” dilemma.
Jerry Grey is a consultant in public policy to the American Institute of Aeronautics and Astronautics, Reston, Va., and a professor emeritus of aerospace engineering at Princeton University.