The Space Reviewin association with SpaceNews

Pete Worden thinks that lunar resources, privately developed and self-financed, can help solve the global warming problem. (credit: J. Foust)

Exploiting the Moon and saving the Earth

There has been a lot of debate in recent months regarding how to return to the Moon, and especially since the release of NASA’s Exploration Systems Architecture Study (ESAS) in September. Less has been said, though, about what people and/or robots will do once they get there. Not that there’s any shortage of ideas: from studying lunar geology and using it as a platform for astronomy to establishing tourist resorts and a separate home for humanity beyond the Earth. None of those ideas, though, has managed yet to resonate with the public.

So how about saving the world? The idea of using lunar resources to prevent or reverse environmental degradation of the Earth is not new: many have proposed harvesting helium-3 from the Moon for fusion reactors that don’t exist yet; others have suggested manufacturing and/or establishing solar power facilities there. (See “Review: Gaia Selene”, The Space Review, September 6, 2005.) Now another innovative, out-of-the-box thinker, astronomer and retired Air Force general Pete Worden, has a very different idea for how to save the Earth using the Moon. While his idea may be no less outlandish—or feasible—than prior ideas, it does demonstrate the brainstorming going on to try and develop a rationale for lunar exploration and exploitation.

Building infrastructure

Before unveiling his world-saving proposition during an October 21 speech at the Space Frontier Conference in Los Angeles, Worden first talked about the roles of the public and private sector. Worden turned to two key words invoked in the initial announcement of the Vision for Space Exploration: affordability and sustainability. To help achieve that, “the private sector must play not just a role, but a dominant role.”

To achieve an affordable and sustainable exploration vision, Worden believes, “the private sector must play not just a role, but a dominant role.”

The government, Worden believes, is best fit for providing the infrastructure needed for lunar exploration, what he called the “roads and commodes” it provides on Earth. “That’s a function that governments do really well,” he said. “It doesn’t take a lot of imagination, but it does take persistence.” For the Moon, that infrastructure comes in several forms, including communications, PNT (position, navigation, and timing, provided on Earth by GPS), “situational awareness” (maps and other remote sensing techniques), and power.

Even here there is a role for the private sector. One model for infrastructure building, Worden noted, is the transcontinental railroad built in the US in the 1860s: it was built privately, financed by the large land grants given to the builders by the government. “With private ownership you can finance just about anything,” he noted. The second approach is government-funded and operated infrastructure, such as GPS. However, Worden believes GPS hasn’t reached its full potential because there is no private ownership; he sees Europe’s Galileo system, a public-private partnership, as “a move in the right direction”.

That infrastructure, once in place, opens up a number of possible uses of the Moon, including options for the private sector usually associated only with the government. One example is astronomy: while normally linked with government efforts funded by NASA and NSF, Worden noted that many terrestrial telescopes, even some of the large next-generation telescopes under development, are privately funded to the tune of $500 million to $1 billion. A large liquid-mirror telescope on the Moon, 20 to 30 meters in diameter, could stare at one point in the sky and see objects as dim as magnitude 37 or 38—faint enough to look back to just 100 million years after the Big Bang. Such a telescope could cost about $1 to 2 billion—within the budgets of private financiers—if “significant infrastructure” to support the observatory is in place. (Worden has been studying the development of such a telescope under a grant from the NASA Institute for Advanced Concepts.)

The Moon’s biggest asset, Worden believes, is what it doesn’t have: an ecosystem. “The Moon is a place where we can do things that are perhaps too dangerous to do on Earth,” he said. This could include performing nanotechnology research there, thus avoiding concerns about ecophagy: out-of-control nanobots turning everything into “gray goo”, as some opponents of nanotech fear. The Moon could also be a quarantine zone for samples returned from Mars, in the event the discovery of life on Mars precludes a direct return of Martian samples to the Earth.

Ten billion ways to stop global warming

All those ideas, though, paled in comparison to what Worden described next: a solution to the problem of global warming. Although not addressing the causes of global warming—natural, man-made, or some combination—he saw three solutions to the problem. One is to roll back technology “and live the way we did a century ago”, an alternative that most, including Worden, would find unpalatable. The second is to reduce greenhouse gas emissions through the use of alternative fuels, nuclear power, and the like. While this has “great potential”, he noted, this approach is also fraught with “political issues” that could hinder their adoption.

Worden’s solution is deceptively simple: erect a shield at the Earth-Sun L1 point, about 1.5 million kilometers from the Earth in the direction of the Sun.

The third, as Worden modestly put it, is to change the fundamental physical constants of the universe. That might seem outlandish at first—Worden likened it to something that Q, the omnipotent nemesis from the Star Trek universe, would do—but what he really had in mind was the solar constant, the amount of sunlight that falls on the Earth. That value isn’t really constant, and has changed over time. Moreover, Worden believes it’s possible for humans to change it.

Worden’s solution is deceptively simple: erect a shield at the Earth-Sun L2 point, about 1.5 million kilometers from the Earth in the direction of the Sun. A shield about 1,600 kilometers across would be sufficient to block two percent of the incident solar radiation, decreasing the solar “constant” and thus solving the global warming problem.

The general idea itself is not that original: Worden credited a paper by James Early in the Journal of the British Interplanetary Society in the late 1980s for the concept. Worden’s implementation would be a massive undertaking, featuring 10 billion spacecraft, each 14 by 14 meters across, arrayed in a three-dimensional checkerboard. The heart of each spacecraft would be a thin block of dispersive glass, weighing no more than one kilogram, manufactured on the Moon. In reality these spacecraft would be transparent, Worden explained: rather than blocking sunlight they would instead disperse it by about one degree, enough to miss the Earth.

Worden said that such spacecraft could be manufactured on the Moon, but would require a major industrial base: 1,000 factories on the lunar surface that each produces 1,000 spacecraft a day for 30 years. He estimates the total cost for such a system to be in the “few trillions” of dollars. That cost doesn’t assume any significant decrease in the cost of space access: he estimates that each factory will require between one and ten tons of material from the Earth, which could be launched from the Earth for all 1,000 factories for well under one trillion dollars even at a typical contemporary launch cost of $20,000 per kilogram.

“We have to start thinking about space as a solution,” he said. “This is an idea whose time has come.”

Nonetheless, with costs of that order of magnitude, one might imagine that such a venture would be solely within the domain of governments. Worden, though, sees private enterprise taking the lead. In a system analogous to the land grants awarded to the builders of the transcontinental railroad, companies that deploy such systems would qualify to receive “carbon credits” for mitigating the effects of atmospheric carbon dioxide, such as those proposed under the Kyoto Protocol. A system of 324 spacecraft alone, Worden estimates, would be worth 6,000 tons of carbon credits. Those credits could then, in turn, be sold on the open market. The result is a system that could be, in Worden’s opinion, “self-financing”, although how much such carbon credits will be worth is an open question.

But, as someone asked Worden after his speech, if this system is privately developed, what’s to prevent someone from blocking ten percent of sunlight, instead of two, and selling—or ransoming—access to it? “That’s where governments have to say that there has to be some level of regulation,” Worden admitted. “Unlimited capitalism is just as evil as unlimited government.”

While the specific concept may seem overwhelming, Worden believes the underlying idea is valid and critical. “We have to start thinking about space as a solution,” he said. “This is an idea whose time has come.”