Archaeologists are increasingly discovering that the best way to find out what is hidden below the ground is to take to the skies. According to an article in the May 2014 issue of the Journal of Archaeological Science, researchers last summer employed a pilotless aircraft to learn more about an ancient village that lurks beneath the layers of dusty soil and sagebrush of remote northwestern New Mexico.
University of Arkansas archaeologist Jesse Casana and University of North Florida professor John Kanter outfitted a remote-controlled, eight-rotor mini helicopter with a heat-sensing camera that revealed buried structures in the 1,000-year-old settlement known as Blue J, approximately 40 miles south of Chaco Canyon, an ancient Pueblo cultural and religious center. The heat-imaging revealed stone rubble, ceremonial pits and the footprints of houses lurking beneath the desert landscape, discoveries that in the past would not have been possible without disturbing the site.
Kanter told the Associated Press that the use of drones saved archaeologists considerable time and money. “Really within a few hours we were able to survey this area that took me a long time, years of what we call ground reconnaissance and excavation to see what’s below the surface,” he said. “So this is great for quickly and pretty cheaply being able to find sites.” Plus, the aerial information will allow researchers to pinpoint exactly where they should dig.
For decades, archaeologists have known about the promise that heat-imaging holds in locating cultural remains buried underground because bricks and stone walls retain and emit warmth differently than the surrounding soil. However, low-altitude flights were needed in order for aerial thermography to be effective, something that wasn’t technologically or economically feasible until the development of affordable pilotless aircraft. In the past, archaeologists seeking bird’s-eye views needed to access satellite data, strap equipment to kites or balloons or rent crop dusters, but these failed to provide the more detailed views offered by drones and could be expensive. Small drones that can be operated with a radio-controlled handset cost around $1,000, and instructional websites such as DIYdrones.com are democratizing access to technical information.
Archaeologists are employing drones for additional uses besides aerial thermography. They are attaching infrared sensors, magnetometers, barometers and GPS devices on craft to assist in their work. In locations throughout the Middle East and South America that have been prone to looting, archaeologists are mounting video cameras on drones to keep an eye out for vandals, protect sites from destruction and create a digital record of ruins for posterity in case any damage reconstruction needs to be undertaken.
Pilotless aircraft are assisting researchers in creating data-rich, three-dimensional maps of archaeological sites. Since drones skim close to the ground, they can measure topographical changes within an accuracy of half-an-inch. The time-consuming task of mapping that previously had been done by hand and could take months and years can now be done in a matter of days.
Archaeologists are also employing unmanned aircraft to explore remote locations that they cannot safely reach. The flipside is that tomb raiders and antiquities traffickers interested in plundering ancient artifacts could have access to the same capabilities. By making these remote locations more accessible, the risk increases that they will not be kept intact.
While drones hold the promise of revolutionizing archaeology, potential obstacles remain. With current technology, flights usually can last only a maximum of fifteen minutes, and the mini helicopter used by the archaeologists in New Mexico has a tendency to suddenly stop and crash to the ground.
And as drones have proliferated, so have safety and privacy concerns. A Pew Research Center poll released last week found that 63 percent of Americans believe that allowing personal and commercial drones to fly through U.S. airspace would be a change for the worse. While “hobbyists” are allowed to fly drones at low altitudes, the Federal Aviation Administration (FAA) currently prohibits their commercial use. However, the FAA is working to develop operational guidelines on the commercial application of drones by the end of 2015. Any easing of restrictions on the commercial operation of drones holds the promise in aiding the future work of archaeologists.