Measuring the mineral content of arid regions

Teledyne Technologies EverywhereYouLook Measuring the mineral content of arid regions

TELEDYNE TECHNOLOGY IN ACTION

Teledyne Imaging Sensors supplies the “eyes” for JPL’s high-fidelity EMIT imaging spectrometer that is operating on the International Space Station

In July 2022, a new generation of Earth observation instrument was installed on the International Space Station. Developed by NASA’s Jet Propulsion Laboratory, EMIT, the Earth Surface Mineral Dust Source Investigation, will measure the mineral content of arid regions around the world. EMIT is a high fidelity imaging spectrometer that accurately measures the light reflected from the Earth at 286 wavelengths from the ultraviolet to the short-wave infrared (380 to 2500 nm; the human eye can see 400-700 nm). Since materials on the Earth have unique spectral “fingerprints”, the spectra can be used to produce mineral maps, maps of vegetation type and health, and sources of greenhouse gases. Examples of the 8 billion spectra measured on six continents since the start of science on July 27, 2022 are shown below.

Since EMIT commenced science operations, the EMIT science team has identified more than 50 “super-emitters” of methane in Central Asia, the Middle East, and the southwestern United States. Methane’s spectral fingerprint and maps of three super-emitters are shown below.

A methane plume at least 3 miles (4.8 kilometers) long billows into the atmosphere south of Tehran, Iran. The plume, detected by NASA’s Earth Surface Mineral Dust Source Investigation mission, comes from a major landfill, where methane is a byproduct of decomposition. Credits: NASA/JPL Caltech

The cube (left) shows methane plumes (purple, orange, yellow) over Turkmenistan. The rainbow colors are the spectral fingerprints from corresponding spots in the front image. The blue line in the graph (right) shows the methane fingerprint EMIT detected; the red line is the expected fingerprint based on an atmospheric simulation. Credits: NASA/JPL Caltech

Identifying anthropogenic sources of methane is very important to reduction of global warming of the Earth. While carbon dioxide is the dominant source of greenhouse gas effects, methane is a growing issue since methane emissions are increasing and methane is 80 times more effective than carbon dioxide for trapping the Earth’s heat. Methane has a much shorter “lifetime” in the Earth’s atmosphere than does carbon dioxide. Methane will persist for about a decade in the Earth’s atmosphere whereas carbon dioxide lingers for centuries. Elimination of sources of methane emissions will have a much faster effect than reduction of carbon dioxide.

JPL has developed and deployed several generations of imaging spectrometers and EMIT utilizes decades of technology advancements including a compact Dyson optical design (see below) that includes a high precision optical slit and diffraction grating, all designed and fabricated at JPL.

F/1.8 Dyson Spectrometer - Credit: NASA/JPL Caltech

F/1.8 Dyson Imaging Spectrometer Credits: NASA/JPL Caltech

Teledyne Imaging Sensors CHROMA-A 1280 x 480 pixel Visible-SWIR FPA (380-2500 nm) Credits: NASA/JPL Caltech

The detector for EMIT is produced by Teledyne Imaging Sensors (TIS) in Camarillo, California. TIS has worked with JPL since the 1990s to advance the performance of imaging arrays that simultaneously detect light from the ultraviolet through the shortwave infrared. The CHROMA-A image sensor used in EMIT has over 600,000 pixels and is mounted in a package that was optimized for the Dyson spectrometer design. A variable anti-reflection that is applied to the surface of the infrared detector is specifically tuned for the wavelengths that land on different regions of the detector.

Teledyne Imaging Sensors has had a multi-decade partnership with JPL on imaging spectrometers that are being used in seven space missions to the Moon, Mars, Jupiter’s moon Europa, and Earth observation. In addition, most of JPL’s airborne imaging spectrometers have used Teledyne’s sensors. “Working with JPL is one of the most enjoyable collaborations of my career. It is very gratifying to know that Teledyne contributes to scientific advancements that benefit our society”, states Teledyne Imaging Sensors President Dr. James Beletic. “I expect that the success of EMIT will spark a new generation of high-fidelity spectral measurement satellites”.

NASA published two press releases on the EMIT spectrograph and science on October 25, 2022. The press releases can be found at:

https://www.nasa.gov/feature/jpl/nasa-dust-detective-delivers-first-maps-from-space-for-climate-science
https://www.nasa.gov/feature/jpl/methane-super-emitters-mapped-by-nasa-s-new-earth-space-mission