EMIT Instrument’s First Light

This image shows the first measurements taken by NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) from aboard the International Space Station at 7:51 pm PDT (10:51 pm EDT) on July 27, 2022, as it passed over western Australia. The image at the front of the cube shows a mix of materials in western Australia, including exposed soil (brown), vegetation (dark green), agricultural fields (light green), a small river, and clouds. The rainbow colors extending through the main part of the cube are the wavelengths of light (in nanometers), or spectral fingerprints, from corresponding spots in the front image.

The line graph (Figure 1) shows spectral fingerprints for a sample of soil, vegetation, and a river from the image cube. Radiance indicates the amount of each wavelength of light reflected from a substance. Researchers use the combination of radiance and wavelength to determine a substance’s spectral fingerprint.

Developed by NASA’s Jet Propulsion Laboratory in Southern California, EMIT works by measuring hundreds of wavelengths of light reflected from materials on Earth. Different substances reflect different wavelengths of light, producing a kind of spectral fingerprint that, when collected by an imaging spectrometer and analyzed by researchers, reveal what they are made of.

When science operations begin later in August 2022, EMIT’s primary mission will be to collect measurements of 10 important surface minerals in regions between 50-degrees south and north latitudes in Africa, Asia, North and South America, and Australia. The minerals include hematite, goethite, illite, vermiculite, calcite, dolomite, montmorillonite, kaolinite, chlorite, and gypsum. The compositional data EMIT collects will help scientists study the role of airborne dust particles in heating and cooling the Earth’s atmosphere on global and regional scales.

Data from EMIT will be delivered to the NASA Land Processes Distributed Active Archive Center (DAAC) for use by other researchers and the public.

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