The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, will measure the height of a changing Earth – one laser pulse at a time, 10,000 laser pulses a second.  

• Launched in 2018, ICESat-2 will carry a laser altimeter that detects individual photons, allowing scientists to measure the elevation of ice sheets, sea ice, forests and more in unprecedented detail.  
• Our planet’s frozen and icy areas, called the cryosphere, are a key focus of NASA’s Earth science research.  

• ICESat-2 will help scientists investigate why, and how much; our cryosphere is changing in a warming climate.  
• The satellite will also measure heights across Earth’s temperate and tropical regions, and take stock of the vegetation in forests worldwide. 

Source: NASA