Nasa launches satellite to study ice changes on Earth

Pablo Tucker
September 17, 2018

NASA's Ice, Cloud and land Elevation Satellite-2, or ICESat-2, lifted off at 9:02 a.m. EDT (6:02 a.m. PDT or 1302 GMT) from Space Launch Complex-2 at Vandenberg Air Force Base in Southern California. "ICESat-2 is going to do cutting-edge, scientific data gathering". The time it takes for the light to bounce back to the satellite helps scientists work out distance and height of the reflecting surface.

This marks the final mission of the Delta II rocket, which first launched on February 14, 1989, and launched 155 times including ICESat-2.

The new laser will fire 10,000 times in one second, compared to the original ICESat which fired 40 times a second.

The satellite can track the state of the Earth's ice in detail from around 500km about the surface. ICESat-2 is the NASA's most advance laser instrument - the Advanced Topographic Laser Altimeter System, or ATLAS.

Meanwhile, the ICESat-2 mission is getting underway. ATLAS will primarily be used to measure the elevation of ice sheets and changes in their size, but will also measure the height of vegetation on land.

ICESat-2 is a successor to the ICESat satellite that collected information on ice cover and other Earth science data from 2003 to 2010. ICESat-2 will bounce three pairs of parallel laser beams continuously off the planet, collecting the reflection with sensitive vacuum tubes.

This design allows ICESat-2 to calculate the slope of a surface, which, if not accounted for, could appear as changes in elevation - a problem NASA discovered with ICESat's single-laser system, GLAS. Only about a dozen photons return to the satellite, where they bounce off a 2.6-foot (0.8 meter) reflective beryllium mirror into a sensor.

Liftoff occurred slightly later than iniitially planned to give the team time to assess a questionable temperature reading involving the rocket's second stage. Going into Saturday's flight, the boosters had chalked up 154 launches with only one outright failure in 1997, 100 flights ago. Consequently, the spacecraft will provide data for every season of the year.

The mission is meant to last three years but has enough fuel to continue for 10, if mission managers decide to extend its life. CalPoly's DAVE satellite will try out a technology to dampen vibrations on spacecraft, two ELFIN satellites built at UCLA will study space weather, and the University of Central Florida's SurfSat will test materials created to protect spacecraft from electrical discharges.

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