NASA detects methane leaks – from a satellite in space

Even a methane cloud may have a silver lining. 

The Porter Ranch methane leak was the biggest natural gas disaster in US history, but NASA used it to the advantage of science. A research team with NASA's Jet Propulsion Laboratory used the months-long incident to conduct an opportunistic research study that highlighted the potential for space-based instruments in detecting gas leaks. 

“For the first time – to our knowledge, anyway – we’ve been able to see the methane plume from space,” NASA scientist David Thompson told The Washington Post. “And this is important because it sort of presages the possibility of using other instruments that are focused on methane in order to do similar things on a much wider scale.”

The unprecedented size of the leak from the Southern California Gas Company gas fields – 100,000 tons of methane released over three months – created a significant opportunity to study the effective methods for detecting and studying such leaks from space. Their findings have been accepted for publication in the journal Geophysical Research Letters.

NASA researchers did this while working with a host of equipment disadvantages. The satellite they repurposed is 16 years old and ran out of fuel five years ago, so the shifts in orbit left it pointing its spectrometer toward the leak at mid-morning, the "wrong" time of day for good imaging, Jason Henry reported for the San Gabriel Valley Tribune.

The spectrometer itself, called Hyperion, is designed to study specific targets for mining, forestry, or agriculture, not analyze plumes of methane gas. Hyperion "just happens" to have imaging capabilities in a range of spectra that included infrared, which is what the NASA team eventually used to take images of the methane.

"In the future, hopefully, we’ll have more sensitive instruments that can do an even better job, now that we’ve shown it’s possible," Dr. Thompson told the San Gabriel Valley Tribune.

Despite the equipment challenges, Hyperion conducted three separate flyovers and gathered information each time. The data from space were consistent with measurements taken closer to Earth. 

The images the researchers released show variation even within the size and location of the methane plume. They relate the movement of the methane plume to the geography below, suggesting that more purpose-specific equipment could assist efforts to control the greenhouse gas movement or locate yet-unknown leaks. 

"What we’re all driving towards is understanding the human portion of the global methane budget,” Thompson told the San Gabriel Valley Tribune. “I think that orbital observations can contribute to that understanding.”

Scientists are particularly interested in the findings because of their focus on methane, which contributes to greenhouse gas warming in ways not entirely understood. This research shows the potential for space-based research to study the quickly moving gas, and better equipment could offer a more global survey of how the gas is actually impacting Earth's atmosphere, according to a NASA release.

“Future satellite systems that focus on methane could be much more sensitive to an event like this one,” Thompson told The Washington Post.