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FACULTY P RO F I L E
Hardening Optical Fiber for Space Kelly Simmons-Potter has taken her radiation-hardening research to the source to help make space-based systems resistant to damage from the sun.
K
elly Simmons-Potter, professor of electrical and computer engineering and optical sciences and a pioneer in radiationhardened materials for extreme environments, has taken her research to the source to help make spacebased systems resistant to radiation damage from the sun.
are resistant to damage, not an easy task considering the natural testing environment is several hundred miles above the Earth’s protective atmosphere. Radiation-hardened materials are usually tested in terrestrial simulation facilities, with only one type of radiation tested at a time. But, “when you’re in space, it’s a combined environment with all those different sources of radiation,” said Potter. “You can’t re-create that on Earth.”
So Potter secured a spot for her radiationhardened optical fiber aboard the Materials International Space Station Experiment-7, In the Arizona Materials Lab, Kelly Simmons-Potter, chair of the American or MISSE-7. The Ceramics Society’s glass and optical materials division, and graduate experiment, led by student Brian Fox inspect their just-returned-from-space, radiationhardened optical fibers. the Naval Research Laboratory, included Reaching for a pair of dollar-store Potter’s sheathed optical fibers doped salt shakers, Potter explained that with the rare-earth metals erbium and one shaker was a familiar clear glass ytterbium. The fibers were contained but that the other shaker had been in what resembled an open suitcase, subjected six years ago to gamma and they were attached to the space rays, a type of ionizing radiation, and station’s exterior during a 45-minute turned black. Radiation damage like spacewalk in November 2009. this is not good for optical fiber, which is being considered for a wide range Repeated space shuttle launch delays of space-based telecommunications kept the doped optical fibers in space equipment. for 18 months. Finally, in mid-2011, Potter’s experiment, the last of the Just like in the salt shaker that turned MISSE-7 payload removed from the from transparent to opaque, optical shuttle, returned to the UA. Although fiber, spun threads of glass that the sheathing surrounding the optical use light signals to carry data, can fibers had become brittle, the fibers darken and stop transmitting light were intact. when exposed to ionizing radiation from the sun in near-Earth orbit. The “By testing the optical fibers in a key is to make radiation-hardened combined space environment, we space-based optical systems that were able to identify fibers that
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University of Arizona College of Engineering
“By comparing spacebased results to terrestrial test data, we can evaluate the validity of Earth-based testing in simulated space environments.” Kelly Simmons-Potter, professor of electrical and computer engineering and optical sciences
exhibit better radiation-hardening and wavelength regions where the worst damage occurs, as well as the fundamental reasons for the radiationinduced damage,” said Potter. “Most importantly, by comparing spacebased results to terrestrial test data, we were able to evaluate the validity of Earth-based testing in simulated space environments.”
Three years later, Potter’s research group, one of only a few in the world doing this type of research, is still publishing findings. Much of the funding for Potter’s research, which aims to develop radiation-hardened materials that can last up to 20 years in space, comes from the U.S. Department of Energy and Sandia National Laboratories.
Contact
Kelly Simmons-Potter 520.626.0525 kspotter@ece.arizona.edu