Space Sunshade Might Be Feasible In Global Warming Emergency

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Space Sunshade Might Be Feasible In Global Warming Emergency

... Angel, a University of Arizona Regents' Professor and one of the world's foremost minds in modern optics, directs the Steward Observatory Mirror Laboratory and the Center for Astronomical Adaptive Optics. He has won top honors for his many extraordinary conceptual ideas that have become practical engineering solutions for astronomy.

For the past year, Angel has been looking at ways to cool the Earth in an emergency. He's been studying the practicality of deploying a space sunshade in a global warming crisis, a crisis where it becomes clear that Earth is unmistakably headed for disastrous climate change within a decade or two.

Angel presented the idea at the National Academy of Sciences in April and won a NASA Institute for Advanced Concepts grant for further research in July. His collaborators on the grant are David Miller of the Massachusetts Institute of Technology, Nick Woolf of UA's Steward Observatory, and NASA Ames Research Center Director S. Pete Worden.

Angel is now publishing a first detailed, scholarly paper, "Feasibility of cooling the Earth with a cloud of small spacecraft near L1," in the Proceedings of the National Academy of Sciences. The plan would be to launch a constellation of trillions of small free-flying spacecraft a million miles above Earth into an orbit aligned with the sun, called the L-1 orbit.

The spacecraft would form a long, cylindrical cloud with a diameter about half that of Earth, and about 10 times longer. About 10 percent of the sunlight passing through the 60,000-mile length of the cloud, pointing lengthwise between the Earth and the sun, would be diverted away from our planet. The effect would be to uniformly reduce sunlight by about 2 percent over the entire planet, enough to balance the heating of a doubling of atmospheric carbon dioxide in Earth's atmosphere....