Understanding the causes and magnitude of change in the cryosphere remains a priority for earth science research. Over the past decade, NASA earth observing satellites have documented a decrease in both the extent and thickness of Arctic sea ice, and ongoing loss of grounded ice from the Greenland and Antarctic ice sheets. Understanding the pace and mechanisms of these changes requires long-term observations of ice sheets, sea ice thickness and sea ice extent. In response to this need, NASA’s Goddard Space Flight Center (GSFC) is developing the ICESat-2 mission, a nextgeneration laser altimeter designed to measure changes in ice sheet elevation, sea ice thickness, and vegetation canopy height. Scheduled for launch in late 2017 with a three year mission life, ICESat-2 will use a photon-counting micropulse laser altimeter, the advanced topographic laser altimeter system (ATLAS) instrument to collect these key data.