Assessment of the Ice, Cloud, and Land Elevation Satellite-2 Performance Against Prime Mission Science Requirements

The Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) is a NASA Earth observing satellite mission that provides global elevation measurements using the Advanced Topographic Laser Altimetry System (ATLAS). ICESat-2 was launched in September 2018 and completed its prime mission of 3 years of on-orbit science data collection in December 2021. ICESat-2, as the successor mission to ICESat (2003–2009) (Schutz et al., 2005, https://doi.org/10.1029/2005gl024009), was designed to provide global elevation measurements of Earth's surfaces. Changes in elevation, such as those over glaciers, ice sheets and sea ice, are some of the most critical observations for characterizing and understanding Earth's dynamic processes and the response to climate variability. The overarching scientific goals of ICESat-2 are associated primarily with the cryosphere, but from a space-based platform, the altimeter measurements serve a wide range of science disciplines. Prior to launch during the early mission development phase, the Level 1 Science Requirements were established, which at the time were some of the most stringent metrics created for space-based altimetry. These requirements were the primary drivers of both the instrument technology development and the mission operational strategies. Here, we evaluate each of the science requirements using the science data collected over the prime mission timeline of 3 years. We conclude from our analyses that the mission has successfully met each of the Level 1 Science Requirements. Further, we evaluate the onboard consumables (fuel and laser energy) and demonstrate that the satellite's operational lifetime could potentially last an additional ∼10 years.