NASA is getting ready to launch a cutting-edge, laser-armed satellite tv for pc that may spend three years learning Earth’s altering ice sheets from above.
Known as the Ice, Cloud and Land Elevation Satellite tv for pc-2 (ICESat-2), the mission is at the moment scheduled to launch in mid-September. The satellite tv for pc will have the ability to measure the altering thickness of particular person patches of ice from season to season, registering will increase and reduces as small as a fifth of an inch (half a centimeter).
“The areas that we’re speaking about are huge — suppose the dimensions of the continental U.S. or bigger — and the adjustments which are occurring over them could be very small,” Tom Wagner, a NASA scientist learning the world’s ice, mentioned throughout a information convention yesterday (Aug. 22). “They profit from an instrument that may make repeat measurements in a really exact method over a big space, and that is why satellites are a perfect solution to examine them.” [How NASA Is Tracking Earth’s Melting Arctic Sea Ice (Video)]
Whereas the mission is optimized for learning ice on the poles, its information must also assist scientists learning forests across the planet.
ICESat-2, which value a little bit over $1 billion and is concerning the measurement of a Good automobile, will observe two earlier main NASA initiatives to watch ice thickness.
In 2003, the authentic ICESat started seven years of laser-aided measurements of ice peak, bouncing a single laser off the floor of the ice. As a result of ICESat-2 wasn’t able to launch when the unique mission ended, NASA designed a stopgap airplane-based mission known as Operation IceBridge to trace significantly essential areas of ice.
NASA has excelled at measuring the world ice covers for many years now, watching ice sheets shrink and develop in two dimensions because the seasons change and the planet warms. However as anybody who has held an ice dice is aware of, ice is available in 3D, and space-based cameras battle to measure that third dimension — therefore, the lasers.
Up to now, these lasers have introduced disturbing information. “What ICESat discovered is that the ocean ice is definitely thinning,” Wagner mentioned. “We have in all probability misplaced over two-thirds of the ice that was once there again within the ’80s.”
The brand new spacecraft will produce far more detailed information than the unique mission and extra fixed information than IceBridge.
“ICESat-2 actually is a revolutionary new instrument for each land ice and sea ice analysis,” Tom Neumann, NASA’s ICESat-2 deputy challenge scientist, mentioned throughout the information convention. Sea ice is especially sophisticated, for the reason that laser should measure the distinction between ice floor and ocean floor, which could be just some centimeters aside. “It truly is an unbelievable engineering feat, nevertheless it’s one which the science critically depends upon,” he mentioned.
Here is how the brand new mission works: ICESat-2 will orbit about 300 miles (500 kilometers) above Earth’s floor carrying an instrument known as the Superior Topographic Laser Altimeter System (ATLAS). The instrument will continually emit a laser beam of inexperienced gentle, which shall be cut up into six separate beams because it leaves the satellite tv for pc. The beams will then bounce off the floor of the ice in a grid sample. Many of the photons within the laser beams shall be misplaced, however a handful will make their method again to the satellite tv for pc.
And the satellite tv for pc can time how lengthy that round-trip took right down to the closest billionth of a second. “ATLAS basically acts like a stopwatch,” Donya Douglas-Bradshaw, instrument supervisor for the laser, mentioned throughout the information convention. “The ATLAS laser fires 10,000 pulses a second, with a trillion photons in every shot. Every time the laser fires, it begins the stopwatch.” Scientists then convert that point right into a distance, calculating the peak of the floor at that location. [2 Satellites Will Probe Earth’s Massive Ice Sheets (Video)]
Whereas a lot of ICESat-2’s scientific worth lies in its laser, its orbit over Earth can also be crucially vital. The spacecraft will basically circle from pole to pole, however fastidiously aligned to retrace its tracks. “The orbit is designed in order that after 91 days, which is 1,387 particular person orbits of the Earth, it precisely repeats itself,” Doug McLennan, ICESat-2 challenge supervisor at NASA Goddard, mentioned throughout the information convention. “This permits the mission to have a look at the identical piece of Earth in every of the 4 seasons.”
The spacecraft is scheduled to launch from Vandenberg Air Pressure Base in California on Sept. 15, throughout a window that opens at 5:46 a.m. native time (eight:46 a.m. EDT, 1246 GMT) and closes at eight:20 a.m. native time (11:20 a.m. EDT, 1520 GMT). ICESat-2’s launch would be the final voyage of United Launch Alliance’s Delta II rocket, which has seen greater than 150 launches over its almost 30-year profession.
After the launch, the crew behind ICESat-2 will spend two months commissioning the spacecraft to ensure every part is working correctly earlier than it begins gathering science information. The mission is scheduled to final for 3 years, though the spacecraft will carry sufficient gas to doubtlessly keep at work for greater than 10 years, ought to NASA select to increase its duties.
As soon as the spacecraft begins its observations, scientists may have entry to a wealth of latest information concerning the Earth’s ice sheets and the way they’re altering over time.
“Within the half a second that it takes an individual to blink, ICESat-2 will gather 5,000 elevation measurements in every of its six beams,” Neumann mentioned. “That is each minute of each hour of every single day for the following three years.”
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