TechConnect - The Nano Issue

he University of Arizona’s
resident Angel still looks
skyward for answers to global
warming, but his passion for
cooling the planet no longer
focuses on the vast, orbiting sunshade he
proposed years ago.

Indeed, the noted astronomer and founder and scientific director of the university’s Steward Observatory Mirror Lab has moved on in his quest to find ways to reduce consumption of fossil fuels. He’s now intent on capturing the sun’s rays—in a very precise way, of course.

“I’m working on how to do solar energy right…how to reduce CO2 by doing solar energy right,” explains British-born Roger Angel.

More specifically, that means he—and a small team of researchers, all working in the university’s world-class mirror lab located below Arizona Stadium—are using his knowledge of optics and mirrors to design mirrors that can focus incredibly intense sunlight onto commercial photovoltaic cells. And although Angel is not incorporating nanotechnology himself on his project, one of his research partners is using the technology. Yong-Hang Zhang, director of the Center for Nanophotonics at Arizona State University, has been charged with the task of creating a more efficient photovoltaic cell that Angel eventually hopes to use in place of the commercial ones.

Angel is trying to find a way to make solar energy inexpensive and more efficient, with the long-term goal of finding a way for utility companies to mass produce energy at a low cost, thereby reducing society’s dependence on fossil fuels. Right now, he says, solar energy is too expensive to do on a grand scale. Angel points out that about only one-tenth of 1 percent of electricity on the power grid in the United States today is solar. But one thing’s for sure: He couldn’t be in a better place to do such research.

“We have sunshine. As a solar resource, this is as good as it gets,” Angel says. “The U.S. is blessed. Arizona has enough land and sun to provide all the energy needs for the U.S. We just have to figure out how to capture it for not too much money.”

Nick Woolf, a longtime colleague and friend of Angel’s, is an adviser on the project. While he can’t reveal too much, Woolf says two reasons the experiments are going well is that Angel takes the glass as it comes out of the factory and shapes it right away, and that as little steel as possible is used in the mounting process. Incidentally, although the glass Angel typically works with to make mirrors is called borosilicate and comes with a hefty price tag, the glass he’s using for his solar energy efforts

is just the stuff found in regular windows.

And progress is being made, Angel notes. The evidence? Since early this year, his team has been able to melt holes in quarter-inch-thick steel using a 10-foot parabolic mirror.

“That’s our party trick,” he says, a certain glee in his lilt, “to show that we can make mirrors of very good quality.”

As for his sunshade, which was something of a media sensation a few years back and even was featured in the Discovery Project Earth television series, Angel modestly points out that the idea of shading the planet from space is “an old one.”

He notes that researcher James Early wrote a paper two decades ago that set forth the basics about such a project. But while he says Early believed a sunshade erected in space would have to wait until the moon was colonized, Angel didn’t think humankind could wait that long. And the way Angel figured it, the sunshade would need to be about 1 million square miles big, would take about 20 to 30 years to develop and launch, and would cost roughly $5 trillion.

“Five trillion sounded like a lot then,” he

Research Laboratory in Sunnyvale, Calif., wrote in an e-mail message that he was involved with the sunshade project while working with Angel as a fellow faculty member at the UofA. The government agency eventually opted out of supporting the project.

“After assuming my current job as NASA Ames director and, based on my interest in this area, we sponsored a weekend workshop on this and related topics,” Worden says. “Following the workshop, NASA, as (former NASA administrator) Dr. (Michael) Griffin indicated, assessed the topic, including the workshop report, and determined that this area is not in our responsibilities.”

Ken Caldeira, director of the Department of Global Ecology at the Carnegie Institution for Science at Stanford University, is also familiar with Angel’s work and calls the professor “a very bright and clever person.” In an e-mail message, Caldeira adds that while he thinks Angel’s work should be supported by NASA, he does not think the sunshade proposal is something he sees happening any time in the coming decades. But it’s a good idea to at least hold on to the plans, just in case, he added.

We have sunshine.

As a solar resource, this is as

good as it gets. — Roger Angel, UofA astronomer

says, “but it doesn’t sound like so much today, not if it’s a matter of saving the planet.”

The sunshade proposal called for trillions of super-light spacecrafts to be deployed about 1 million miles above the Earth at what is known as the L-1 point. The crafts, which essentially would be lenses that would allow light to pass through them, would bend the sunlight just enough to reduce its effect on Earth by about 2 percent. The plan was not a complete solution to global warming, he adds.

“Cooling the planet by shading it is by no means a fix,” he says, but it was a good place to start.

Angel says his sunshade project did receive a small grant from a NASA group early on, but says NASA officials later told him they “would not fund it, partly because it’s not their mandate and partly because they don’t want to look silly.”

Michael Griffin, former NASA administrator, declined via e-mail to comment for this story, noting he has no expertise in the subject. But Pete Worden, director of NASA’s Ames

“I think his proposals are an interesting theoretical possibility and a possible long-term end game should we fail to reign in our carbon addiction,” Caldeira wrote.

Whatever happens, Angel says, his ideas are published and available for public consideration. But after putting his thoughts and calculations down on paper, he says, he felt it was up to others to bring the project to fruition.

“What I’ve done is what I can do,” he says. “I think I moved the ball forward from where it was 20 years ago.”

No doubt the solar energy industry will benefit as well from the analysis of this “mirror master,” as Angel has been called. As for whether all these monumental concerns— global warming, melting ice caps, carbon emissions—ever keep him up at night, Angel answers like the pragmatic soul and true scientist he is.