MARK WILLIAMSON / SCIENCE PHOTO LIBRARY MARK WILLIAMSON / SCIENCE PHOTO LIBRARY
Close-up of solar cells under test at Biosphere 2 (note colours caused by diffraction). Biosphere 2, near Tucson, Arizona, was developed in the late 1980s for research into how natural environments create habitable conditions for human sustainability ('biosphere 1' being the Earth). In the 1990s it explored the possible use of closed biospheres in space exploration (a group of 'biospherians' spent up to two years in a closed environment).
Model release not required. Property release not required.