Innovative infrared sensors developed by NASA increase resolution for Earth and space imaging, promising advancements in environmental monitoring and planetary science.
The recently developed infrared camera, boasting high resolution and a suite of lightweight filters, holds promise for analyzing sunlight reflected from Earth’s upper atmosphere and surface, improving forest fire alerts, and determining the molecular composition of other planets.
These cameras feature sensitive, high-resolution strained-layer superlattice sensors, initially developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with funding from the Internal Research and Development (IRAD) program.
Due to their compact design, low weight, and adaptability, engineers like Tilak Hewagama are able to tailor them for a variety of scientific applications.
Enhanced Sensor Capabilities
“By attaching filters directly to the detector, we eliminate the significant mass associated with traditional lens and filter systems,” explained Hewagama. “This results in an instrument that is not only low in mass but also compact in its focal plane, which can be cooled for infrared detection with smaller, more efficient coolers. The resolution and accuracy of these instruments are advantageous for smaller satellites and missions.”
Engineer Murzy Jhabvala spearheaded the initial development of sensors at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and is also at the forefront of the current efforts to integrate filters.
Jhabvala also spearheaded the Compact Thermal Imager experiment aboard the International Space Station, showcasing the new sensor technology’s durability in space and its significant contributions to Earth science. The capture of over 15 million images in two infrared bands led to Jhabvala, along with NASA Goddard colleagues Don Jennings and Compton Tucker, receiving the agency’s Invention of the Year award for 2021.
Breakthroughs in Earth and Space Observation
The test data yielded comprehensive insights into wildfires, enhanced knowledge of the vertical configuration of Earth’s clouds and atmosphere, and documented an updraft phenomenon known as a gravity wave, which is generated by wind interacting with Earth’s topography.
The revolutionary infrared sensors employ layers of repeating molecular structures to engage with individual photons, the basic units of light. These sensors can discern a greater number of infrared wavelengths at a superior resolution of 260 feet (80 meters) per pixel from orbit, a significant improvement over the 1,000 to 3,000 feet (375 to 1,000 meters) resolution achievable with existing thermal cameras.
The effectiveness of these thermal imaging cameras has attracted funding from NASA’s Earth Science Technology Office (ESTO), Small Business Innovation and Research, among other initiatives, to expand their scope and enhance their applications.
Jhabvala and the NASA Advanced Land Imaging Thermal IR Sensor (ALTIRS) team are creating a six-band model for the current year’s LiDAR, Hyperspectral, & Thermal Imager (G-LiHT) airborne initiative. This unprecedented camera will record surface temperatures and facilitate the monitoring of pollution and fire at high frame rates.
Next-Generation Fire Imaging
NASA Goddard Earth scientist Doug Morton is heading an ESTO project that is focused on the development of a Compact Fire Imager, which will be used for detecting and predicting wildfires.
“We won’t be seeing a reduction in fires, so we’re focusing on comprehending how fires release energy throughout their life cycle,” Morton explained. “This knowledge will aid in our understanding of fires’ evolving nature in a world that is becoming more prone to burning.”
CFI will track both the intense fires that emit a higher amount of greenhouse gases and the cooler, smoldering embers and ashes that generate more carbon monoxide and airborne particles such as smoke and ash.
“Those are crucial elements in ensuring safety and comprehending the greenhouse gases emitted through combustion,” stated Morton.
Following the testing of the fire imager in airborne campaigns, Morton’s team plans to equip a fleet of 10 compact satellites. This will enable the provision of comprehensive global fire data with an increased frequency of imagery each day.
He stated that, when combined with next-generation computer models, this information could assist the forest service and other firefighting agencies in preventing fires, enhancing safety for frontline firefighters, and safeguarding the lives and property of those in the path of fires.
Probing Clouds on Earth and Beyond
Equipped with polarization filters, the sensor is capable of measuring the way ice particles scatter and polarize light in Earth’s upper atmospheric clouds, according to NASA Goddard Earth scientist Dong Wu.
This application is set to complement NASA’s PACE mission — Plankton, Aerosol, Cloud, ocean Ecosystem — Wu mentioned, which unveiled its initial light images last month. Both applications measure the polarization of light waves’ orientation in relation to their direction of travel across various parts of the infrared spectrum.
“The PACE polarimeters are designed to monitor visible and shortwave-infrared light,” he detailed. “The mission’s emphasis will be on aerosol and ocean color sciences, derived from daytime observations. The new Infrared polarimeter will measure cloud and surface properties across mid- and long-infrared wavelengths during both daytime and nighttime observations.”
In a collaborative endeavor, Hewagama is teaming up with Jhabvala and Jennings to integrate linear variable filters, enhancing the detail captured within the infrared spectrum. These filters are instrumental in disclosing the rotation and vibration of atmospheric molecules, as well as the composition of the Earth’s surface.
The technology may also be advantageous for missions targeting rocky planets, comets, and asteroids, according to planetary scientist Carrie Anderson. She mentioned that it could detect ice and volatile compounds released in massive plumes from Saturn’s moon Enceladus.
“They are essentially ice geysers,” she explained, “which, although cold, emit light that falls within the detection limits of the new infrared sensors. Observing the plumes with the Sun as a backdrop would enable us to determine their composition and vertical distribution with great precision.”
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