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Counting on NASAs ICESat-2



The ICESat-2 satellite is subjected to one final test before it is placed in the rocket. ICESat-2, scheduled for September 1
5, will accurately measure the altitude of the Earth's ice and monitor changes. Credit: USAF 30th Space Wing / Timothy Trenkle

NASA is in the process of bringing the most advanced laser instrument of its kind into space. The Ice, Cloud and Land Elevation Satellite-2, or ICESat-2, will provide critical observations on how ice sheets, glaciers and sea ice change, leading to insight into how these changes affect people where they live ,

The launch is scheduled for September 15, and as we count down the days, we list 10 things you should know about ICESat-2:

1 Space Laser

ICESat has only one scientific Instrument -2, but it's a miracle. The Altitude Topographic Altimeter System (ATLAS) measures altitude by precisely measuring how long individual photons of light from a laser take to leave the satellite, ricochet off the earth, and return to the satellite. Hundreds of people at NASA's Goddard Space Flight Center in Greenbelt, Maryland, worked to build this smart-car-sized instrument to exacting requirements so scientists could measure tiny changes in the ice of our planet.

2 types of ice

distress all ice is the same. Land ice, such as the ice floes in Greenland and the Antarctic, or glaciers that cover the Himalayas, forms when snow falls over centuries and forms compacted strata. When it melts, it can flow into the ocean and raise sea levels. Sea ice, on the other hand, forms when ocean water freezes. It can last for years or a single winter. If the sea ice disappears, it will not affect the sea level (think of a melting ice cube in your drink), but it can change climate and weather patterns far beyond the poles.

3-Dimensional Earth

ICESat-2 will measure altitude to see how much glaciers, sea ice and ice sheets are rising or falling. NASA's satellite fleet collects detailed images of our planet showing the changing scale of features such as ice sheets and forests, and with the data from ICESat-2, scientists can add the third dimension – elevation – to these portraits of the Earth.

4 Seasons, 4 Measurements

The ICESat-2 orbit will make 1,387 unique soil tracks around the Earth in 91 days – and then begin the same basic pattern again in the beginning. This will allow the mission to measure the same soil traces four times a year, and scientists will observe how glaciers and other frozen features change with the seasons, including over winter.


532 nm wavelength

The ATLAS instrument measures ice with a laser that glows at 532 nanometers – a bright green in the visible spectrum. When these laser photons return to the satellite, they pass through a series of filters that block any light that is not exactly at that wavelength. This helps to flood the instrument with all other naturally reflected shades of sunlight.

6 Laser Beams

While the first ICESat satellite (2003-2009) measured ice with a single laser beam, ICESat-2 splits its laser light into six beams – better to cover more ground (or ice). The arrangement of the rays in three pairs will also allow scientists to determine the slope of the surface they measure.

7 kilometers per second

ICESat-2 will fly over the planet at 7 km per second (7.2 km) per second to create an orbit around the Earth in 90 minutes. The orbits were tuned to converge on the 88-degree width lines around the poles to focus data coverage in the region where scientists expect the greatest change.

800-picosecond Precision

All these elevation measurements This results from timing the individual laser photons on their 600-mile round trip between the satellite and the earth's surface – a journey set at 800 picoseconds. That's an accuracy of less than a billionth of a second. NASA engineers had to build a stopwatch-like device because no existing timers meet the stringent requirements.

9 years of Operation IceBridge

Measuring ICSat-2, ICESat-2 contributes to the NASA record of ice heights with the first ICESat and continued Operation IceBridge, a nine-year mission over the Arctic and the United States Antarctica is flying. The campaign, which bridges the gap between the two satellite missions, has flown since 2009, taking height measurements and documenting the changing ice.

10,000 pulses per second

The ICESat-2 laser triggers 10,000 times in one second. The original ICESat fired 40 times a second. More impulses mean more height data. If ICESat-2 flies over a football field, it would require 130 measurements between the end zones; its predecessor on the other hand would have carried out a measurement in each end zone.

The ICESat-2's fast-firing laser, combined with the instrument's precision timing, sensitive photon detection technology and other features, will enable the ICESat-2 mission to measure the average annual change in large ice sheets down to the width of a pencil ,


Further information:
NASA launches an advanced laser to measure Earth's changing ice

Provided by:
Goddard Space Flight Center of NASA


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