However, AVIRIS-5, short for Airborne Visible/Infrared Imaging Spectrometer-5, shares many similarities with sensors used to study distant planets, and that is just one of the numerous tasks envisioned.
AVIRIS-5, roughly the size of a microwave oven, identifies the spectral “fingerprints” of minerals and other compounds in reflected sunlight. The sensor, like its cousins flying in space, takes advantage of the fact that all molecules, from rare earth elements to flower pigments, have distinct chemical structures that absorb and reflect light at different wavelengths.
The technique was developed at NASA’s Jet Propulsion Laboratory in Southern California in the late 1970s. Over the years, imaging spectrometers have visited every major rocky body in the solar system, from Mercury to Pluto.
They have mapped the Martian crust in complete spectral detail, discovered lakes on Titan, and followed mineral-rich dust across the Sahara and other deserts. One is on its way to Europa, Jupiter’s ocean moon, to search for the chemical elements required to sustain life.
NASA’s Moon Mineralogy Mapper, an imaging spectrometer, was the first to detect water on the lunar surface in 2009.
That dataset continues to drive our investigations as we look for in situ resources on the Moon.
Robert Green, Senior Research Scientist, NASA Jet Propulsion Laboratory
Green has contributed to multiple spectroscopy missions across the solar system.
Prisms, Black Silicon
While imaging spectrometers differ in their goals, they share some common hardware, such as mirrors, detector arrays, and electron-beam gratings, which are used to collect light shimmering off a surface and then divide it into its constituent colors, similar to a prism.
Many of the best-in-class imaging spectrometers in use today were made feasible by components developed at NASA JPL's Microdevices Laboratory. Instrument makers there integrate advances in physics, chemistry, and material science with the classical qualities of light established by scientist Isaac Newton in the seventeenth century. Newton's prism experiments demonstrated that visible light consists of a rainbow of colors.
Today, NASA JPL engineers use sophisticated materials like black silicon – one of the darkest substances ever created – to improve performance. Under a strong microscope, black silicon resembles a forest of prickly needles. Nanoscale structures etched by lasers or chemicals capture stray light in their spikes, preventing it from interfering with the sample.
Treasure Hunting
The optical methods utilized at the Microdevices Laboratory have improved steadily since the first AVIRIS instrument flew in 1986. Four generations of these sensors have now been deployed in the sky, assessing erupting volcanoes, unhealthy crops, ground zero rubble in New York City, and wildfires in Alabama, among other applications.
The latest iteration, the AVIRIS-5, has twice the spatial resolution of its predecessor and can discern regions ranging from less than a foot (30 cm) to around 30 feet (10 m).
So far this year, it has completed over 200 hours of high-altitude flights across Nevada, California, and other Western states as part of the GEMx (Geological Earth Mapping Experiment).
The missions are carried out by NASA's ER-2 aircraft, which operate from the agency's Armstrong Flight Research Center in Edwards, California. The effort is the airborne component of a broader USGS initiative known as the Earth Mapping Resources Initiative (Earth MRI), which aims to update surface and subsurface mapping across the country.
Since 2023, the NASA-USGS team has collected data across more than 366,000 square miles (950,000 km2) of the American West, where arid, treeless stretches are ideal for mineral spectroscopy.
An intriguing early discovery is hectorite, a lithium-bearing clay found in the tailings of an abandoned mine in California, among other locations. Lithium is one of about 50 minerals at risk of supply chain disruption that the USGS has identified as vital to national security and the economy.
One of the long-term goals of GEMx, as stated by Dana Chadwick, an Earth system scientist at NASA JPL, is to assist communities in deriving new value from old and abandoned mining sites. Additionally, the initiative aims to identify sources of acid mine drainage, which can occur when waste rocks weather and leach into the environment.
The breadth of different questions you can take on with this technology is really exciting, from land management to snowpack water resources to wildfire risk. Critical minerals are just the beginning for AVIRIS-5.
Dana Chadwick, Earth System Scientist, NASA Jet Propulsion Laboratory
GEMx interface: Spectroscopy animation
NASA’s AVIRIS flies aboard a research plane in this animation, detecting minerals on the ground such as hectorite – a lithium-bearing clay – by the unique patterns of light that they reflect. The different wavelengths, measured in nanometers, look like colorful squiggles in the box on the right. Video Credit: NASA’s Conceptual Image Lab