An innovative University of Nebraska-Lincoln-designed drone designed to ignite prescribed fires in grasslands and forests was used successfully April 22 to burn 26 acres of restored tallgrass prairie at Homestead National Monument of America near Beatrice.

In addition to testing the capabilities of the unmanned aircraft system under development by Husker researchers Carrick Detweiler and Sebastian Elbaum and their team, the experiment could result in additional joint activities between the researchers and the National Park System and the Department of Interior.

For example, David Niemi of the Midwest Regional Fire Management Office said discussions are underway that could lead to a more extensive test of the UNL technology at Badlands National Park in South Dakota later this year. There, the rugged terrain poses a bigger danger to firefighters and a drone might prove even more useful in combating woody growth and exotic species that crowd out native plants and increase the danger of wildfires.

During the past 11 years, five firefighters have died in wildland fires, said Mark Engler, superintendent at Homestead National Monument.

“A tool like this might be one of the answers to making these fires safer,” he said. “This is an important test. It is important to us to help UNL develop this technology.”

Co-founders of the Nebraska Intelligent Mobile Unmanned Systems, or NIMBUS, Laboratory, Detweiler and Elbaum have been working for nearly two years with a multidisciplinary team to develop aerial robots small enough to fit in a firefighter’s backpack, yet smart enough to navigate a dangerous environment.

“UNL is pioneering this merging of two very risky, highly regulated technology fields: fire and unmanned aviation,” Elbaum said.

Craig Allen, a professor who is an expert on invasive species management, is a part of the team. He said prescribed burns are one of the most effective tools for controlling invasive species, restoring grassland ecologies and preventing wildfires. Prescribed burns are particularly successful in controlling Eastern Red Cedar, an invasive tree species that is destroying many grasslands in the Great Plains.

The trees are fire-prone, he said, and a wildfire in an area overgrown with cedars poses a threat to life and property.

“We need to burn more, but we can’t because we’re restricted by logistics,” Allen said.

Another team member, Dirac Twidwell, is a Husker rangeland expert who studies prescribed burns. He has participated in 150 prescribed burns during his career. He said the April 22 fire demonstrated how drones could make fires safer and easier to manage.

Homestead Monument routinely uses prescribed burns to manage its tallgrass prairie, which is one of the oldest restored prairies in the nation. Without the burns, Twidwell said, the prairie would have been overtaken by cedars and shrubs.

“There’s nothing that can do what fire does,” he said.

The device tested April 22 was the fourth prototype developed by Elbaum and Detweiler. A couple more versions are likely within the next couple years. The drones previously have been tested indoors and on private land.

After trained firefighters began burning the perimeter of the parcel to be burned, the drone flew out about 200 yards over the interior of the test area before turning around to drop small ignition balls – one every eight seconds on its return trip.

The device works by injecting balls containing a chemical with a liquid that creates a chemical-reaction based flame after a minute or two. The balls are dropped to the ground through a chute. Several minutes after the drone passed over, circles of fire began emerging in a line through the center of the field.

In addition to dropping ignition balls, the drone was flown over fire lines and at different heights to gather data about fire conditions. Elbaum and Detweiler said they will spend coming weeks analyzing the information that was collected to further improve the technology.

“We see a lot more interesting research ahead in terms of further automation and safety,” Detweiler said.

Other members of the research team included Brittany Duncan, assistant professor of computer science and engineering, and students James Higgins, Evan Beachly, Christian Laney and Rebecca Horzewski.

In addition to Homestead National Monument and the university, other collaborators included the National Park Service’s Midwest Region Fire and Aviation Program and the Service’s national-level Branch of Aviation; and the Department of the Interior’s Office of Aviation Services.

The Federal Aviation Administration gave permission for the test after the device was reviewed and approved by NASA, Detweiler and Elbaum said. NASA oversees air transportation research as well as space research.

Elbaum and Detweiler have applied for patent protection for their devices through NUTech Ventures, the university’s technology transfer entity. After the device was made public in October, they received dozens of inquiries from landowners, conservationists and private businesses. Earlier this spring, they conducted a preliminary test during a prescribed burn of more than 2,000 acres of private land in southwest Nebraska, conducted by the Loess Canyons Rangeland Alliance.