ICESat-2 (Ice, Cloud, and land Elevation Satellite-2) is a satellite operated by NASA that was launched in 2018 to measure changes in Earth's ice sheets, glaciers, sea ice, and vegetation. It does this by using a laser instrument called the Advanced Topographic Laser Altimeter System (ATLAS) to make highly accurate measurements of the height of Earth's surface. The satellite is able to make measurements with an accuracy of less than 1 centimeter, which allows scientists to monitor changes in the ice sheets and other features with unprecedented detail. The data collected by ICESat-2 will be used to study the effects of climate change and improve our understanding of the Earth's cryosphere.