Researchers from NASA’s Jet Propulsion Lab and the University of California, Merced, are testing a drone-mounted methane-detection device that sports a miniaturized version of the NASA Mars Curiosity Rovers’ sensor array.
“We utilized NASA’s investments to make our detector so small and able to withstand some of the issues associated with UAVs,” says Lance Christensen, OPLS principal investigator at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., about the small, open-path laser spectrometer (OPLS) sensor mounted on his test drone.
It’s a miniature, $200,000 version of Mars Curiosity Rover’s larger spectrometer. The sensor is sensitive enough to measure air particulates at 20 parts per billion each second, and its protective housing costs more than the device itself, adds Christensen. The rover uses its methane sensor to find fumes of gas in the hope of locating methane-producing life forms on Mars. But Christensen and his research partners from the Mechatronics, Embedded Systems and Automation (MESA) Lab at UC Merced use their sensor to find methane leaks from pipelines.
During tests, Christensen’s team releases a small to moderate amount of methane in a known location, then flies the drone to see how quickly it can detect and pinpoint the methane plume, he says. Similar to the Picarro Surveyor by Picarro Inc., Santa Clara, Calif., the NASA sensor bounces a laser beam between two mirrors to detect methane (ENR 9/7/15 p. 62).
The best way to visualize what the sensor sees is to imagine a plume of cigarette smoke and how it disperses in the air, says Christensen. His algorithm is designed to pick out that plume; the drone flies by the plume until it pins down the location.
“It gets sharper and sharper the closer we get to the source,” says Christensen. Though the team has a pilot flying and monitoring the drone during tests for safety purposes, they also are toying with sensor and flight automation to make the drone an automated, methane-seeking system.
Christensen says pilot projects with the state of California are in the near future. “I see that happening rather quickly,” adds Christensen.