From his office in Athens, Ohio, geographer James Lein sees a coal barge on the Ohio River, a refinery in Marietta, a power line running
through Athens County. The objects flash on his computer screen in a rainbow of fluorescent images captured by satellites orbiting 500 miles above Earth. The observations may seem ordinary, but the task is revolutionary: to identify areas most vulnerable to terrorist attack by using a network of satellites.

With the aid of a $93,000 grant from NASA, Lein studies images collected by Landsat 7 and Aster satellites to map a detailed inventory of southeastern Ohio, noting facilities such as schools, chemical plants, key public buildings, and pipelines. The research will identify areas susceptible to terrorist threats by monitoring physically remote locations, geographic characteristics of a region, and population density. Lein is testing the technology first in Ohio. If it’s successful, it could be used on a national scale.

“What we want to be able to do is not let (September 11) happen again,” Lein says. “We can certainly begin to look at what’s taking place in and around us and start thinking in a more defensive posture.”

The satellite research could show, for example, that a chemical plant sits on a rural road with little traffic or no protective fences. By identifying this problem, policy makers and local homeland security officials can ensure the remote plant will not be an easy target for terrorists.

In addition, the data monitor temperature changes which can signal that a structure, such as a pipeline or electrical line, is under attack. The Landsat satellite orbits the Earth every 16 days, allowing data to be updated almost every two weeks.

The satellites, supported by NASA and the U.S. Geological Survey, collect images through “remote sensing,” a process that records energy reflected by the land’s surface in wavelengths of light (Perspectives Spring/Summer 2001). The numerical data from these wavelengths differ, allowing scientists to decipher between a wheat field, a forest, or even a parking lot. The satellites then transmit this information to a ground station where the data are processed into an image.

Scientists have used this information to monitor such issues as crop inventory, urban planning, water pollution, and sea surface temperature. For the purposes of homeland security, Lein will identify possible target areas from an overhead shot, and make the data available to government officials.

For more information, search the Research Communications
Web site www.ohio.edu/researchnews/, keyword “satellites.”