NASA’s Space Laser to Track Melting Poles of Earth

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Ice, Cloud and land Elevation Satellite (ICESat-2) will bounce laser light off Earth’s surface to record changes in its elevation

NASA is set to launch its US$ 1 billion Ice, Cloud and land Elevation Satellite (ICESat-2) from Vandenberg Air Force Base in California on September 15, 2018. The satellite will primarily track melting poles of the Earth by bouncing a laser on the surface. The new satellite is a successor to ICESat-1 and is laced with multibeam laser instrument, whereas ICESat-1 had a single laser beam. With three pairs of parallel beams, ICESat-2 can scan along multiple paths at once. In resolution, ICESat-1 took readings once every 150 meters along its track, whereas ICESat-2 will record elevations every 70 centimeters with the laser-firing frequency of 10,000 per second. Such frequent leads to relatively weak pulse and enables the satellite to capture faint reflections. Moreover, the satellite uses a small telescope to funnel light to sensitive vacuum tubes that can detect single photons.

Earlier, crystals used to amplify the lasers of ICESat-2 cracked when their metallic mounts expanded unexpectedly. Therefore, the original launch date in 2016 was delayed for repairs that increased the expanses to around US$ 1 billion. Once launched, the first task for ICESat-2 will be to assess the East Antarctic Ice Sheet, which is the Earth’s most massive ice sheet. Although, extreme cold and high elevation can protect the East Antarctic Ice Sheet from major ice loss, researchers aim to understand the effects of snowfall, melting ice, and shifting bedrock on small changes in elevation.

Moreover, the satellite is expected to focus on the crags of the Antarctic Peninsula that is responsible for a quarter of the continent’s ice loss. The ICESat-2 will also be used to monitor grounding lines of ice sheets, where glaciers draining to the ocean first float free of the bedrock and become ice shelves. The satellite is developed to measure the canopy height of high-latitude forests, when it is not watching ice sheets. It will providing climate scientists with a proxy measure for the carbon stored in trees. The article was published in the journal Science on September 11, 2018.

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