NASA research into flexible, high-temperature space materials may some day improve personal fire shelter systems and help wildland firefighters better survive dangerous wildfires.
NASA’s Langley Research Center in Hampton, Virginia, is working with the U.S. Department of Agriculture’s Forest Service to see if flexible thermal protection system technology being developed for space entry vehicles could also work to protect firefighters caught in a raging forest fire.
Two NASA Langley researchers, Anthony Calomino and Mary Beth Wusk, reached out to the Forest Service following the loss of 19 firefighters in central Arizona in June, 2013. Members of the elite Granite Mountain Hotshots were trapped and used emergency fire shelters in an attempt to survive during the Yarnell Hill fire.
“I was watching the news after the loss of the Granite Mountain Hotshots, and I thought, just like I am sure other people did, what could have been done to save them,” said Wusk. “What if the firefighters had been cloaked in some of the spacecraft heat shield materials we had spent years developing?”
She and Calomino weren’t sure exactly where to start, so they sent an email to the Forest Service.
“During the last six years we have been working with a NASA team of thermal material specialists that are designing lightweight, multi-layered flexible thermal protection systems for space entry vehicles,” the two wrote. “These systems are capable of protecting delicate hardware from temperatures exceeding 3,000 degrees Fahrenheit (1,649 degrees Celsius). With the progress made in material development, we feel we may have a more capable technology that can protect our firefighters under extreme heating conditions.”
Their interest and questions eventually led them to the Forest Service’s National Technology and Development Center (T&D) in Missoula, Montana and Fire Shelter Project leads Anthony Petrilli and Mary Ann Davies. The NASA researchers found that the T&D team was already reviewing the fire shelter design and new materials technology with the goal of producing an improved shelter by 2018.
“Our Technology and Development Program had already been doing market research into materials, laminates or components that might improve heat protection while still maintaining strength, especially as compared to the current wildland firefighter personal fire shelter,” said Petrilli. “So NASA’s call could not have come at a better time.”
Wildland firefighters carry personal fire shelters in the rare event that they get trapped and need to protect themselves from heat, smoke and/or ember showers. Forest Service versions are aluminized cloth tents, shaped like a half-cylinder with rounded ends. They reflect radiant heat and provide a certain amount of breathable air. The Forest Service says fire shelters have saved many firefighter lives, but can be damaged by extensive direct flame contact.
NASA and the T&D team formed a partnership called CHIEFS, which stands for Convective Heating for Improvement for Emergency Fire Shelters. CHIEFS team lead Josh Fody and student interns at NASA Langley immediately began screening candidate materials solutions using a number of test and design methods.
“We initially tested over 100 small samples of different configurations — combinations of layers of space age materials,” said Fody. “Our heat shield is a cone of inflatable rings, covered by a thermal blanket of layers of heat resistant materials, so the configuration we use isn’t exactly what we want for the fire shelters but there are components of it that are. Our testing approach is also a good fit with conditions similar to a fire.”
NASA researchers presented preliminary thermal test results to the Forest Service Fire Shelter Project leads. The next step was to design full-sized prototypes, have them manufactured, and test them in a real world environment. This summer, T&D will partner with the NASA engineers and the University of Alberta in Edmonton, Canada, to conduct real fire tests in a remote section of Canada’s Northwest Territories. The prototype fire shelters will be instrumented to collect thermal and heat flux data inside and out during the experiments. Most of the NASA shelter design examples were made by S.D. Miller and Associates, PLLC, in Flagstaff, Arizona.
“The testing is supposed to happen in Fort Providence, Canada, starting in late June and continuing through the first of July,” said Wusk. “We have three different burns that are scheduled to occur and we’ll be testing 12 shelters.
“The shelter, currently in use, is about the same size and weight as a half-gallon of milk — about 4.3 pounds (1.95 kilograms),” added Wusk.
“The big technical challenge is putting together something better that weighs about the same and is the same size,” said Calomino. “We have something similar to that weight, and we have another design that is heavier but more capable, which perhaps could be left in a truck until it’s needed.”
The NASA researchers who have seen video of previous tests say it is a unique testing environment. The professionals set a controlled fire in a section of forest that contains the sensor-instrumented shelters, while scientists and engineers monitor the blaze from a safe distance. The test is over quickly as the flames burn through the area where the tents are placed. Data is taken on that configuration and the team moves onto the next possible candidate.
NASA Langley engineers say what they’re testing this summer is their first generation of materials. They expect that what they learn from the full-scale burn tests will lead to another generation of shelter designs with better protection that will improve the safety of wildland firefighters.
NASA CHIEFS team lead Fody described the research as “bringing NASA back to Earth,” which the team quickly adopted as a slogan to reflect how they are working to use space technology to improve life at home.