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Some 10,500 years ago, hunters gathered each year near the Beaver River in what is now western Oklahoma. There, they funneled bison into narrow, dead-end arroyos — steep gullies cut into the hillside by the river — where they killed them en masse, sliced off the choicest meat and left behind piles of skeletons.
Walk through western Oklahoma today and there is little visible evidence of that ancient landscape, much less the hunting expeditions it hosted. Few bison remain, and dirt and rocks have filled in many of the arroyos.
But laser-based remote-sensing equipment called lidar can give archaeologists hints of the fossils and bones hidden below the surface. And the technology owes a lot of its development to scientists looking at something very different: planets, moons and asteroids.
In lidar — or light detection and ranging — scanning, one or more lasers sends out short pulses, which bounce back when they hit an obstacle, whether clouds, leaves or rocks. The instrument calculates how long it all took and, using that information, can calculate the distance, explains George Shaw, an engineer at Goddard Space Flight Center.
Shaw is the laser systems lead for the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission, which will use lidar to map an asteroid, helping the mission team select a site to gather samples to bring back to Earth.
Snow on Mars, Bones on Earth
NASA has been incorporating lidar devices into missions dating as far back as the Apollo Program, and its work has helped advance the technology in ways that have paid off for many other applications.
Teledyne Optech, a company that has worked with NASA on multiple missions, designed the OSIRIS-Rex lidar as well as another used on the Phoenix lander that discovered snow precipitating in the Martian atmosphere in 2008.
To get to Mars, Teledyne Optech had to make its device smaller, lighter, more rugged and able to run on very little power — and those same improvements made it much easier to mount them on airplanes on Earth, facilitating the kind of imaging that archaeologists can use.
Indeed, in the Beaver River area, the archaeological research team scanned the landscape with an airborne Teledyne Optech lidar device that benefited directly from the work the company has done at NASA — and the scans helped uncover important history.
“You’ll never find bison bones with airborne lidar, but you can find the geological features that suggest a place to look,” explains Meg Watters, who specializes in remote sensing and 3D imaging for archaeology.
A Revolutionary Technique
The Teledyne Optech lidar builds a 3-D model of the surface that includes the grass, bushes and trees, but it can also produce a “bare-earth” version, stripping all that away. That allows archaeologists to “see structures or features that were so overgrown that they wouldn’t be obvious at all to someone on the ground,” explains Paul LaRoque, vice president of special projects at Teledyne Optech.
The lidar imaging has “been useful in delineating where we need to concentrate our efforts,” says archaeologist Lee Bement, who leads research in the Beaver River area. “It saved us a lot of time and effort.”
Data from lidar scans have helped lead to several other highly touted discoveries in recent years, including pinpointing the site of the legendary lost “Ciudad Blanca” in Honduras. That team turned to the Houston-based National Center for Airborne Laser Mapping, which uses Optech’s Titan and Gemini lidars.
And although funding constraints mean archaeologists are not the biggest market for lidar instruments, they are increasingly turning to the technology wherever possible to gain insights for their research.
For instance, University of Connecticut Ph.D. candidate Katharine Johnson and her advisor were able to advance the study of landscape history in New England thanks to publicly available lidar scan data.“The advent of lidar has basically revolutionized the way we are able to study the landscape,” she says.
NASA has a long history of transferring technology to the private sector. Each year, Spinoff profiles about 50 NASA technologies that have transformed into commercial products and services, demonstrating the wider benefits of America’s investment in its space program. Spinoff is a publication of the Technology Transfer Program in NASA’s Space Technology Mission Directorate.