The 2017-2027 Earth Science Decadal Survey recommended high-resolution global surface topography and vegetation (STV) as a targeted observable. The Concurrent Artificially-intelligent Spectrometry and Adaptive Lidar System (CASALS) is a swath-mapping altimetry lidar that employs a novel transmitter and grating method in combination with a state-of-the-art, high-speed, photon-sensitive detector array. Previous NASA altimetry lidars have acquired Earth’s surface height measurements in either 1D within single laser footprints or 2D by overlapping footprints along the ground track. CASALS provides 3D swath mapping of Earth surface heights and vegetation waveforms with fine cross-track spatial resolution that are especially advantageous for characterizing the structure of forests. Given this, CASALS is a strong candidate for the lidar measurements desired as part of a future Surface Topography and Vegetation (STV) space mission. The CASALS instrument concept was successfully demonstrated via rooftop testing in Sep. 2024 and airborne flights in Nov. 2024. Here, we describe the airborne instrument, demonstration flight performance, and preliminary spaceborne design.