This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A team of researchers at NASA's Goddard Space Flight Center (GSFC) has developed a new instrument designed to eliminate blind spots between lines of lidar data on Earth's surface. Built with support from NASA's Earth Science Technology Office (ESTO), the Concurrent Artificially-intelligent Spectrometry Lidar System (CASALS) could help researchers map the features of Earth's surface in detail.
Rather than mechanically steering a laser with moving mirrors, CASALS steers light using wavelength itself, generating a continuous, 3D swath of the ground below. John Yorks, a physical research scientist at GSFC and principal investigator for CASALS, explained that the instrument features a novel transmitter and optical grating system that manipulates laser pulses without heavy, failure-prone motorized mirrors. Instead, CASALS uses a fast-pulsing, tunable "seed" laser centered at 1,040 nanometers, rapidly cycling through 256 unique wavelengths as it pulses through an optical component with a microscopic pattern of ridges called a transmission grating.
At this point, the physics of diffraction takes over. Because light bends at slightly different angles depending on its exact wavelength, the grating naturally "steers" each of the 256 pulses into a distinct position across the flight path. This nonmechanical approach paints a continuous 3D swath of the ground.
Not only does this eliminate the large unmapped gaps left between the isolated tracks of legacy spaceborne lidars, but stripping away moving parts reduces the instrument's size, weight and power (SWaP) requirements. This makes it more reliable for the harsh environment of space. Another key innovation within CASALS is its detector array.
This component features a high quantum efficiency (QE), a variable that describes how effectively a detector converts incoming light (photons) into an electrical signal. CASALS operates at 80% QE. This means CASALS wastes almost none of the light that makes it back to the sensor.
With QE that high, CASALS can detect much weaker return signals, allowing it to collect useful measurements from darker surfaces or through denser vegetation. This technology isn't limited to a laboratory environment. In November 2024, an airborne CASALS prototype flew aboard NASA's B200 King Air aircraft.
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