the following article was featured in Nasa's 2015 Spinoff Magazine:
Before astronauts are able to undertake long-term missions into the solar system, they’ll need technologies that allow them to grow their own fruits and vegetables. For years, NASA has been advancing technologies such as artificial lighting, plant monitoring devices, and growth chambers to advance that goal.
But it’s one thing to grow plants; it’s another to keep them from aging prematurely. The culprit is ethylene—a naturally occurring gas emitted from plants that hastens ripening. Comprised of hydrogen and carbon, ethylene can induce decay when left to accumulate in enclosed spaces such as a spacecraft. To forestall that process, in the 1990s the Wisconsin Center for Space Automation and Robotics, a NASA Research Partnership Center located at the University of Wisconsin–Madison, developed an ethylene reduction device.
Also known as an ethylene “scrubber,” the device works by drawing in air through tubes coated with titanium dioxide. When a built-in ultraviolet light shines onto the coat, the gas is converted into trace amounts of water and carbon dioxide, which are actually good for plants. The scrubber was first flown on Space Shuttle Columbia mission STS-73 in 1995 and proved successful in preserving a crop of potato seedlings. Subsequent missions used and improved the technology.