Fabrics Protect Sensitive Skin from UV Rays
- Sunday, 01 November 2009
Originating Technology/NASA Contribution
Beginning in 1968, NASA began researching garments to help astronauts stay cool. The Agency designed the Apollo space suits to use battery-powered pumps to circulate cool water through channels in the inner layers of the garments. This led to commercial cooling vests for patients with heat control disorders (first featured in Spinoff 1979) and for workers in heat stress occupations (featured in Spinoff 1982).
Space suits not only keep astronauts cool, but also use multiple layers of heavy fabric to block the Sun’s ultraviolet (UV) rays from burning the skin. The first commercial cool suits had been designed primarily to keep patients cool, but were not designed specifically to block UV rays.
In 1997, late Johnson Space Center engineer Robert Dotts, assistant director of Technology Transfer and Commercialization, headed a team to continue the research from the first generation of cool suits after receiving a request for help from a family with two children suffering from life-threatening sun sensitivities. In order to both prevent the Sun’s light from damaging their skin and also to keep the patients cool, Dotts hoped to develop UV-blocking technology in a fabric that—unlike in a bulky space suit—could remain comfortable, light, and breathable in the sun and heat. Dotts, engineers Dominic Del Rosso and Evelyne Orndoff, and NASA physician Smith Johnston discussed requirements, identified materials, and then began testing fabrics from private industry at NASA’s White Sands Test Facility.
In the summer of 1997, Dotts contacted Terry Breese, president of Solar Protective Factory Inc. (SPF), a Madison, Wisconsin-based company that had been developing commercial UV-resistant fabrics since 1989. “Dr. Dotts was very concerned about the manufacturing standards and testing methods we employed to measure ultraviolet transmittance,” Breese says, remembering when NASA first contacted his company to request fabrics for testing.
With NASA’s input, SPF developed its “Solarpro-tiferous” process, which enhances fabric reflectivity and UV absorption with special chemical treatments added during the dying process. In this process, SPF uses charcoal, coconut, and titanium in its fabrics to reflect UV rays or to help transfer UV light into heat, which then disperses quickly. Dotts and NASA engineers provided SPF with feedback on fiber structure during development, suggesting combinations of high-loft synthetic fibers and spandex blends to keep the fabric as tightly knit as possible while also being comfortable, breathable, moisture-wicking, and reflective. Too much elasticity, the engineers explained, would allow too much UV light through when the fabric stretched. The team determined the optimal amount of spandex in the suits was 8–9 percent when blended with a high-loft nylon thread. Because of the life-threatening sensitivity of these patients to light or heat, the Johnson team required the fabric, according to Breese, “to perform at the highest possible protection level and still be comfortable.”
The prototypes for the second generation of protective cool suits consisted of a hat, gloves, socks, pants, scarf, goggles, and jacket—truly covering the wearer from head-to-toe—that incorporated the earlier built-in water channels under layers of UV-blocking fabric, thereby protecting patients with both light and heat sensitivities.
Del Rosso, the cooling system specialist on the project, explains that the Johnson team used NASA’s research and experience in cooling astronauts to adapt the cool suits for the young, sun-sensitive patients. These improved cool suits were far lighter than the first generation of cool suits from a decade before, enabling pediatric patients to play outdoors in sunlight for the first time. The new prototypes still used two layers of garments like before, but now the UV-blocking outer fabric was far lighter and more breathable.