Far above the heads of Earthlings, arrays of single-cell creatures are circling Earth in nanostructures. The sample devices are riding on the International Space Station (courtesy of Sandia National Laboratories and the University of New Mexico, NASA and US Air Force) to test whether nanostructures whose formations were directed by yeast and other single cells can create more secure homes for their occupants — even in the vacuum and radiation of outer space — than those created by more standard chemical procedures.