ICESat-2 carries a single instrument – the Advanced Topographic Laser Altimeter System, or ATLAS. Like the altimeter on the first ICESat mission, ATLAS times the travel of laser pulses to measure the distance between the spacecraft and Earth’s surface. Orbiting over the poles, ATLAS will feature new technologies that will allow it to collect a more detailed, precise picture of the heights of the planet’s ice, vegetation, land surface, water and clouds.