EMIT: NASA’s Unexpected Hero in the Climate Crisis

Since launching 16 months ago, the EMIT imaging spectrometer aboard the International Space StationThe International Space Station (ISS) is a large spacecraft in orbit around the Earth that serves as a research laboratory and spaceport for international collaboration in space exploration. It was launched in 1998 and has been continuously occupied by rotating crews of astronauts and cosmonauts from around the world since 2000. The ISS is a joint project of five space agencies: NASA (USA), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). It orbits the Earth at an altitude of approximately 400 kilometers (250 miles), and provides a unique platform for scientific research, technological development, and human space exploration.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>International Space Station has shown an ability to detect more than just surface minerals.

More than a year after first detecting methane plumes from its perch aboard the International Space Station (ISS), data from NASA’s EMIT instrument is now being used to identify point-source emissions of greenhouse gases with a proficiency that has surprised even its designers.

EMIT’s Mission and Capabilities

Short for Earth Surface Mineral Dust Source Investigation, EMIT was launched in July 2022 to map 10 key minerals on the surface of the world’s arid regions. Those mineral-related observations, which are already available to researchers and the public, will help improve understanding of how dust that gets lofted into the atmosphere affects climate.

Detecting methane was not part of EMIT’s primary mission, but the instrument’s designers did expect the imaging spectrometer to have the capability. Now, with more than 750 emissions sources identified since August 2022 – some small, others in remote locations, and others persistent in time – the instrument has more than delivered in that regard, according to a new study published in the journal Science Advances<em>Science Advances</em> is a peer-reviewed, open-access scientific journal that is published by the American Association for the Advancement of Science (AAAS). It was launched in 2015 and covers a wide range of topics in the natural sciences, including biology, chemistry, earth and environmental sciences, materials science, and physics.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>Science Advances.

EMIT identified a cluster of 12 methane plumes within a 150-square-mile (400-square-kilometer) area of southern Uzbekistan on Sept. 1, 2022. The instrument captured the cluster within a single shot, called a scene by researchers. Credit: NASA/JPL-Caltech

Methane Emissions and Climate Change

“We were a little cautious at first about what we could do with the instrument,” said Andrew Thorpe, a research technologist on the EMIT science team at NASAEstablished in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is "To discover and expand knowledge for the benefit of humanity." Its core values are "safety, integrity, teamwork, excellence, and inclusion." NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>NASA’s Jet Propulsion Laboratory in Southern California and the paper’s lead author. “It has exceeded our expectations.”

By knowing where methane emissions are coming from, operators of landfills, agriculture sites, oil and gas facilities, and other methane producers have an opportunity to address them. Tracking human-caused emissions of methane is key to limiting climate change because it offers a comparatively low-cost, rapid approach to reducing greenhouse gases. Methane lingers in the atmosphere for about a decade, but during this span, it’s up to 80 times more powerful at trapping heat than carbon dioxide, which remains for centuries.

When strong winds on one continent stir up mineral rock dust (such as calcite or chlorite), the airborne particles can travel thousands of miles to affect entirely different continents. Dust suspended in the air can heat or cool the atmosphere and Earth’s surface. This heating or cooling effect is the focus of NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) mission. Credit: NASA/JPL-Caltech

Surprising Results

EMIT has proven effective at spotting emission sources both big (tens of thousands of pounds of methane per hour) and surprisingly small (down to the hundreds of pounds of methane per hour). This is important because it permits identification of a greater number of “super-emitters” – sources that produce disproportionate shares of total emissions.

The new study documents how EMIT, based on its first 30 days of greenhouse gas detection, can observe 60% to 85% of the methane plumes typically seen in airborne campaigns.

In a remote corner of southeastern Libya, EMIT on September 3, 2022, detected a methane plume that was emitting about 979 pounds (444 kilograms) per hour. It’s one of the smallest sources detected so far by the instrument. Credit: NASA/JPL-Caltech

Comparison With Airborne Detection

From several thousand feet above the ground, methane-detecting instruments on aircraft are more sensitive, but to warrant sending a plane, researchers need prior indication that they’ll detect methane. Many areas are not examined because they are considered too remote, too risky, or too costly. Additionally, the campaigns that do occur cover relatively limited areas for short periods.

On the other hand, from about 250 miles (400 kilometers) altitude on the space station, EMIT collects data over a large swath of the planet – specifically the arid regions that fall between 51.6 degrees north and south latitude. The imaging spectrometer captures 50-mile-by-50-mile (80-kilometer-by-80-kilometer) images of the surface – researchers call them “scenes” – including many regions that have been beyond the reach of airborne instruments.

“The number and scale of methane plumes measured by EMIT around our planet is stunning,” said Robert O. Green, a JPLThe Jet Propulsion Laboratory (JPL) is a federally funded research and development center that was established in 1936. It is owned by NASA and managed by the California Institute of Technology (Caltech). The laboratory's primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA's Deep Space Network. JPL implements programs in planetary exploration, Earth science, space-based astronomy and technology development, while applying its capabilities to technical and scientific problems of national significance.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>JPL senior research scientist and EMIT’s principal investigator.

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This time-lapse video shows the Canadarm2 robotic arm of the International Space Station maneuvering NASA’s EMIT mission onto the exterior of the station. Extraction from the SpaceXCommonly known as SpaceX, Space Exploration Technologies Corp. is a private American aerospace manufacturer and space transport services company that was founded by Elon Musk in 2002. Headquartered in Hawthorne, California, the company designs, manufactures, and launches advanced rockets and spacecraft. SpaceX's ultimate goal is to reduce space transportation costs and enable the colonization of Mars.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]”>SpaceX Dragon spacecraft began around 5:15 p.m. PDT on July 22 and was completed at 10:15 a.m. PDT on July 24. Portions of the installation have been omitted, while others have been sped up. Credit: NASA

Scene-by-Scene Detections

To support source identification, the EMIT science team creates maps of methane plumes and releases them on a website, with underlying data available at the joint NASA-United States Geological Survey Land Processes Distributed Active Archive Center (LP DAAC). The mission’s data is available for use by the public, scientists, and organizations.

Since EMIT began collecting observations in August 2022, it has documented over 50,000 scenes. The instrument spotted a cluster of emissions sources in a rarely studied region of southern Uzbekistan on September 1, 2022, detecting 12 methane plumes totaling about 49,734 pounds (22,559 kilograms) per hour.

In addition, the instrument has spotted plumes far smaller than expected. Captured in a remote corner of southeastern Libya on September 3, 2022, one of the smallest sources so far was emitting 979 pounds (444 kilograms) per hour, based on estimates of local wind speed.

Reference: “Attribution of individual methane and carbon dioxide emission sources using EMIT observations from space” by Andrew K. Thorpe, Robert O. Green, David R. Thompson, Philip G. Brodrick, John W. Chapman, Clayton D. Elder, Itziar Irakulis-Loitxate, Daniel H. Cusworth, Alana K. Ayasse, Riley M. Duren, Christian Frankenberg, Luis Guanter, John R. Worden, Philip E. Dennison, Dar A. Roberts, K. Dana Chadwick, Michael L. Eastwood, Jay E. Fahlen and Charles E. Miller, 17 November 2023, Science Advances.
DOI: 10.1126/sciadv.adh2391

More About the EMIT Mission

EMIT was selected from the Earth Venture Instrument-4 solicitation under the Earth Science Division of NASA’s Science Mission Directorate and was developed at NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech in Pasadena, California. The instrument’s data is available at the NASA Land Processes Distributed Active Archive Center for use by other researchers and the public.