Two NASA scientists recently returned from a two week, 470-mile (760 kilometers) expedition in one of the most barren landscapes on Earth. NASA cryospheric scientist Kelly Brunt and ICESat-2 deputy project scientist Tom Neumann were mapping a section of the latitude line at 88 degrees south in the South Pole in preparation for the Ice, Cloud and land Elevation Satellite-2 (ICESat-2) mission, which is scheduled to launch in September.

ICESat-2 will use lasers to track changes in ice sheets, sea ice, glaciers and more — all of which belong to Earth's "cryosphere" — and researchers will use that data to investigate the effect of climate change on Earth's sea levels. In order for ICESat-2 to make precise measurements from orbit, scientists needed to collect some data from the ground to calibrate the satellite's instruments. After their trek through Antarctica, Brunt and Neumann discussed their journey in a new video released by NASA.

The two researchers and two other crewmembers drove large, tank-like vehicles called PistenBullies, with 60-foot-long (18 meters) plastic sled trains trailing behind them. The sleds held gear for both science and survival, including the crew's sleeping tents, kitchen tent, fuel, generators and cargo. Scientific instruments pulled along with the rest of Brunt and Neumann's gear helped the scientists collect data that will be used to calibrate ICESat-2 once it launches. [Rugged Antarctica Shows Its Ice in New 3D Map]

"ICESat-2 is all about measuring elevation, and the natural question is, 'How do you know you're getting the right answer?' This is how we will know," Neumann says in the video. "We'll go out and collect a reference data set. We'll be ready to compare and evaluate [and] see how we're doing."

Brunt and Neumann's main goal was to measure the elevation of the ice sheet surface along the area they traversed. The scientists left out "corner cube reflectors" to mark the location of each elevation measurement, Neumann explains in the video. The reflectors were made of bamboo poles that had little pieces of glass about the size of a pinkie fingernail embedded in the cap. This glass is specially made to reflect green laser beams from the satellite once it's in space, allowing the mission's scientists to pinpoint exactly where ICESat-2's measurements are coming from.

Once ICESat-2 has data, it will be compared to Brunt and Neumann's measurements.

"The plan is to repeat this traverse for the next three years — so, four years of data total," Brunt said.

Over the next four years, the 470-mile (760 km) arc Brunt and Neumann measured will become the best-surveyed piece of either of the ice sheets, Neumann said. The combination of the researchers' data and that from ICESat-2's will show how the South Pole's ice sheets are changing year over year. ICESat-2 should be able to measure less than an inch of change, NASA said, which is necessary because even a small amount of melt can contribute to sea level rise.

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