A new, higher-resolution infrared camera equipped with a variety of lightweight filters could probe sunlight reflected from Earth’s upper atmosphere and surface, improve wildfire warnings, and reveal the molecular makeup of other planets. The cameras use sensitive, high-resolution strained-layer superlattice sensors, initially developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, using Internal Research and Development (IRAD) funds.
Their compact construction, low mass and adaptability allow engineers like Tilak Hewagama to adapt them to the needs of a variety of sciences. “Attaching filters directly to the detector eliminates the substantial mass of traditional lens and filter systems,” Hewagama said. “This allows us to create a low mass instrument with a compact focal plane which can now be cooled for infrared detection using smaller, more efficient refrigerators. “Smaller satellites and missions can benefit from its resolution and precision.”
Engineer Murzy Jhabvala led the initial development of the sensor at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as well as leading current filter integration efforts. Jhabvala also led the compact thermal imaging camera experiment on the International Space Station that demonstrated how new sensor technology could survive in space and at the same time it turned out to be a great success for Earth sciences. More than 15 million images captured in two infrared bands earned inventors Jhabvala and NASA Goddard colleagues Don Jennings and Compton Tucker the agency’s Invention of the Year award for 2021.
Test data provided detailed information about the forest firesa better understanding of the vertical structure of Earth’s clouds and atmosphere and captured an updraft caused by wind rising from Earth’s terrestrial features called a gravity wave.
Innovative infrared sensors use layers of repeating molecular structures to interact with individual photons or units of light. The sensors resolve more infrared wavelengths with higher resolution: 80 meters per pixel from orbit compared to 375 to 1,000 meters possible with current thermal cameras.
The success of these heat measurement cameras has attracted investments from NASA’s Earth Sciences Technology Office (ESTO), Small Business Innovation and Research and other programs to further customize their scope and applications.
Jhabvala and NASA’s Advanced Terrestrial Imaging Thermal Infrared Sensor (ALTIRS) team are developing a six-band version for this year’s Airborne LiDAR, Hyperspectral, and Thermal Imaging (G-LiHT) project. This camera, the first of its kind, will measure surface heat and make it possible to monitor pollution and observe fires at high frame rates, he said.
NASA Goddard Earth scientist Doug Morton leads an ESTO project developing a compact fire imager for wildfire detection and prediction. “We’re not going to see fewer fires, so we’re trying to understand how fires release energy throughout their life cycle,” Morton said. «“This will help us better understand the new nature of fires in an increasingly flammable world.”
CFI will monitor both the hottest fires that release more greenhouse gases and the colder, hotter coals and ash that produce more carbon monoxide and airborne particles like smoke and ash. “Those are key ingredients when it comes to safety and understanding the greenhouse gases released by flaring,” Morton said.
After testing the fire imager in aerial campaigns, Morton’s team anticipates equip a fleet of 10 small satellites to provide global fire information with more images per day. Combined with next-generation computer models, he said, “this information can help the Forest Service and other firefighting agencies prevent fires, improve the safety of frontline firefighters, and protect the lives and property of those who live in the area.” path of the fires.”
Equipped with polarization filters, the sensor could measure how ice particles in clouds in Earth’s upper atmosphere scatter and polarize light, said Dong Wu, a scientist at NASA’s Goddard Earth.
These applications would complement the PACE mission (Plankton, Aerosol, Cloud, Ocean Ecosystem) from NASA, said Wu, which revealed its first light images earlier this month. Both measure the polarization of the orientation of light waves relative to the direction of travel from different parts of the infrared spectrum.
“The PACE polarimeters will monitor visible light and shortwave infrared,” he explained. “The mission will focus on aerosol science and ocean color from daytime observations. At mid- and long-infrared wavelengths, the new infrared polarimeter would capture cloud and surface properties from both daytime and nighttime observations.”
In another effort, Hewagama is working with Jhabvala and Jennings to incorporate linear variable filters providing even greater detail within the infrared spectrum. The filters reveal the rotation and vibration of atmospheric molecules, as well as the composition of the Earth’s surface.
That technology could also benefit missions to rocky planets, comets and asteroids, said planetary scientist Carrie Anderson. She said they could identify ice and volatile compounds emitted in huge plumes from Saturn’s moon Enceladus. “They are essentially ice geysers that are, of course, cold, but they emit light within the detection limits of the new infrared sensor. Observing the columns with the Sun as a backdrop would allow us to very clearly identify their composition and vertical distribution,” she concluded.
