ICESat‐2 Early Mission Synopsis and Observatory Performance. Issue 5 (18th May 2021)

• Record Type: Journal Article
• Authors: Magruder, Lori; Neumann, Thomas; Kurtz, Nathan
• Is Part Of: Earth and space science. Volume 8:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-18
• Subjects: ATLAS -- cryosphere -- ICESat‐2 -- laser altimetry -- satellite pointing control -- remote sensing; Space sciences -- Periodicals; Geophysics -- Periodicals; 500.5
• DOI: 10.1029/2020EA001555
• Languages: English
• ISSNs: 2333-5084

Abstract

Abstract: The Advanced Topographic Laser Altimetry System (ATLAS) onboard the NASA Ice, Cloud, and land Elevation Satellite‐2 (ICESat‐2) is the newest Earth observing satellite for global elevation studies. The primary objectives for ICESat‐2 follow the objectives of its predecessor, ICESat and also focus on providing cryospheric measurements to determine ice sheet mass balance, and monitor both sea ice thickness and extent. However, the global observations support secondary science objectives as well such as biomass estimation, inland water elevation, sea state height and aerosol concentrations. Since launch of ICESat‐2, ATLAS has collected more than a trillion measurements. This study provides a mission overview, a description of the operational components that enable the altimeter products for science, on‐orbit observatory performance, and assessment of the spacecraft attitude control systems that enable repeat measurements to within 10 m and pointing control within ±45 m. These metrics should be considered for ground‐based validation campaigns or science investigations. Plain Language Summary: Space‐based remote sensing provides an unequaled point of view for observing changes on Earth's surface. Collecting precise elevation data from this perspective with modern measurement technology holds promise for a wide range of science disciplines given the coverage over all surface types (e.g., land ice, sea ice, inland water, ocean, and vegetation). Over time this high quality data can not only reveal global elevations but elevation change in those regions with repeat measurements. ICESat‐2 carries a state‐of‐the‐art laser ranging system for accurate elevation measurements and utilizes onboard instrumentation and databases to help control the laser pointing enabling repeat measurements and individual geodetic (latitude and longitude) points of interest. The repeat measurements are critical for looking at elevation change over time, while the collection of elevations over specific locations on the Earth enable studies for science and validation efforts. ICESat‐2 has been on‐orbit for over two years and has collected nearly a trillion measurements. Evaluation of the repeat measurements over time indicate the satellite can point to within 10 m while the ability to collect a measurement of a single position on the surface is within the mission specification of ±45 m. Key Points: ICESat‐2 has proven the on‐orbit ability of photon‐counting lidar for precise and accurate space‐based altimetry ICESat‐2 onboard attitude control systems exceed the ±45 m mission requirement for pointing control The satellite is able to follow reference ground tracks to provide repeat measurements within 10 m on average