It will orbit about 300 miles (500 kilometers) above Earth’s surface carrying an instrument called the Advanced Topographic Laser Altimeter System (ATLAS). The instrument will constantly emit a laser beam of green light. The spacecraft will essentially circle from pole to pole, but carefully aligned to retrace its tracks.The mission is currently scheduled to launch in mid-September from Vandenberg Air Force Base in California. Its goal will be to measure the changing thickness of individual patches of ice from season to season, registering increases and decreases as small as a fifth of an inch (half a centimeter). ICESat-2, which cost a little over $1 billion and is about the size of a Smart car.
ICESat-2 artist vision
The new spacecraft will produce much more detailed data. “ICESat-2 really is a revolutionary new tool for both land ice and sea ice research,” Tom Neumann, NASA’s ICESat-2 deputy project scientist, said during the news conference. “The ATLAS laser fires 10,000 pulses a second, with a trillion photons in each shot. Each time the laser fires, it starts the stopwatch.” Scientists then convert that time into a distance, calculating the height of the surface at that location,” Donya Douglas-Bradshaw, instrument manager for the laser explained. For the next three years, in the half a second that it takes a person to blink, ICESat-2 will collect 5,000 elevation measurements in each of its six beams.