NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) will use its advanced laser instrument to measure the average elevation change of Earth’s polar ice, specifically land ice covering Greenland and Antarctica.
What’s intriguing is its accuracy. As ICESat-2 captures 60,000 measurement each second, it’ll reveal ice shifts to within the width of a pencil.
The Advanced Topographic Laser Altimeter System (ATLAS) is tasked with the measurements. The system will record how long it takes for photons to travel from the spacecraft to Earth, and back. The photon’s total time can be converted into distance using the speed of light as a constant. After combining data from its GPS and star tracker cameras to determine the satellite’s location, the distance traveled is finally converted into height.
ATLAS will send pulses at a wavelength of 532 nanometers, and 10,000 times per second. The diffracted optical element will split those pulses into six laser beams. The data returned from Earth filters through a beryllium telescope, which sends the photons to the detector.
According to NASA, “The detector times photons to within a billionth of a second. By combining photon data, ICESat-2 measures height to ~1 inch (3 cm).”
The satellite will travel along an exact path from pole to pole, hitting the same polar regions four times a year. This will provide seasonal and annual elevation data.
“ATLAS required us to develop new technologies to get the measurements needed by scientists to advance the research,” says Doug McLennan, ICESat-2 project manager at NASA’s Goddard Space Flight Center. “That meant we had to engineer a satellite instrument that not only will collect incredibly precise data, but also will collect more than 250 times as many height measurements as its predecessor.”
For a better understanding, if the older version flew over a football field, it would take two measurements—one at each end zone. ICESat-2, however, would ramp that number up to 130 measurements between each end zone.
ICESat-2 is scheduled to launch next month, September 15, and will continue to extend NASA’s polar ice monitoring, which began with the first 2003 ICESat mission.
For more details, enjoy the video below.
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