NASA's CASALS Lidar Achieves High-Resolution 3D Earth Mapping in Air Tests

NASA's Concurrent Artificially-intelligent Spectrometry and Adaptive Lidar System (CASALS) instrument successfully demonstrated 3D mapping capabilities with 22-centimeter horizontal resolution during airborne tests in November 2024[8][18][19]. This new technology, developed at NASA's Goddard Space Flight Center, aims to eliminate blind spots in current lidar data, which leave large areas of Earth unobserved[1][2].

This advancement offers a more complete understanding of Earth, which is important for monitoring carbon cycles, ecosystems, and natural hazards[3][10][18][22]. The detailed 3D mapping capabilities promise better biomass estimations and closer tracking of the cryosphere's response to climate change[18][22].

What the records show

The CASALS instrument integrates adaptive lidar, hyperspectral imaging via a sensor called MiniSpec, and on-board artificial intelligence (AI)[3][16]. Unlike systems with mechanical steering, CASALS directs laser light by manipulating its wavelength. It uses a fast-pulsing, tunable "seed" laser centered at 1040 nanometers, capable of rapidly cycling through 256 unique wavelengths[1][6]. These pulses pass through a transmission grating, which steers the laser across the ground without moving parts, generating a continuous 3D swath of terrain[1][6]. This non-mechanical approach significantly reduces the instrument's size, weight, and power (SWaP) requirements, enhancing its suitability for space deployment[1][6][15]. A key feature is its detector array, which boasts an 80% Quantum Efficiency (QE), enabling the detection of weaker return signals and measurements from darker surfaces or through denser vegetation[6][18].

The timeline

The development of CASALS spanned from January 1, 2020, to December 31, 2022, during which its Technical Readiness Level (TRL) advanced from 2 to 4[16]. The instrument underwent successful rooftop testing in September 2024, followed by airborne demonstrations in November 2024[13]. An airborne CASALS prototype flew aboard NASA's B200 King Air aircraft over Delaware's Great Cypress Swamp[8][18][19]. Flying at an altitude of approximately five kilometers, CASALS produced science-quality datasets with a 22-centimeter horizontal resolution, capable of distinguishing individual tree branches and subtle changes in ground elevation[8][18]. The instrument is scheduled for another flight opportunity in the summer of 2027 as part of the Airborne Surface, Cryosphere, Ecosystem, and Nearshore Topography (ASCENT) campaign[18][19][20][21].

What changed and for whom

Current space-based laser instruments measure Earth's forests and terrain one narrow line at a time from orbit, leaving millions of acres unobserved[2][7]. CASALS is designed to map Earth's surface as continuous three-dimensional swaths, thereby closing these data gaps and providing more comprehensive information[1][5][10]. This capability will provide detailed vegetation structure measurements, enabling more accurate biomass estimations. These estimations are important for understanding carbon sequestration rates and tracking changes in forest health[18]. It will also provide high-priority measurements related to the cryosphere's response to climate change, offering detailed topographical data on ice sheets, glaciers, and snow cover for monitoring ice loss, glacier dynamics, and changes in snow depth[18][22]. These measurements address Earth Science Decadal Survey recommendations for ice elevation and snow depth[22]. CASALS is being considered for future Low Earth Orbit (LEO) missions, including Earth Venture Missions and Surface Topography and Vegetation (STV) missions, potentially as a SmallSat or a mission equivalent to ICESat-2, enabling measurement continuity with previous lidar missions[16][17].

What the subject has said publicly

John Yorks, a physical research scientist at Goddard Space Flight Center and Principal Investigator for CASALS, expressed satisfaction with the instrument's performance. Yorks stated, "I'm very impressed with Guang Yang, Jeffrey Chen, and all our engineers, and how well CASALS performed. This worked really well from the first time we flew it, which is pretty impressive"[18][19]. He also noted, "We are being funded to optimize and improve the performance, and we're also then looking at ways to take the technologies used in the airborne instrument and mature them and prepare them for a spaceborne version in the future"[18][19].

What we could not confirm

Specific details regarding the planned widening of the instrument's swath and precise information about the onboard data processing software that the CASALS team intends to add were not specified[18][19].