Engineers in a clean room at NASA's Jet Propulsion Laboratory in Southern California in April 2023 examine the imaging spectrometer that will ride aboard the first of two satellites to be launched by the Carbon Mapper Coalition. The instrument will help researchers detect emissions of carbon dioxide and methane from sources on Earth's surface from space.

The gold-colored component is the spectrometer, which was developed at JPL. It's designed to receive sunlight reflected from Earth and divide that light into hundreds of distinct colors in the near-infrared and visible portion of the electromagnetic spectrum. By analyzing the light's spectroscopic signature – the wavelengths that show up in the signal as well as those that do not – researchers can determine whether the instrument is observing greenhouse gas emissions and, if so, estimate their concentrations.

The black portion at the base of the instrument is a telescope that captures light from Earth's surface and reflects it into the spectrometer.

When released into the atmosphere, carbon dioxide and methane are the greenhouse gases most responsible for human-caused global warming. Both have unique spectral signatures that make them detectable from space via spectroscopy.

The imaging spectrometer is JPL's contribution to the Carbon Mapper Coalition, a joint effort led by the nonprofit Carbon Mapper that also includes Planet Labs PBC, the California Air Resources Board, Arizona State University, and the University of Arizona. Once the instrument is in orbit, researchers will use its measurements to identify the sources of carbon dioxide and methane plumes it detects. Identification of the origins of emissions is considered the first step towards mitigation.