ICESat-2 fires lasers for the first time, measures Antarctic ice

Oct. 4 (UPI) -- NASA's polar-orbiting probe IceSat-2 fired its laser instrument for the first time this week, yielding the satellite's first height measurement.

The feat happened as IceSat-2 passed over Antarctica. ATLAS, the satellite's laser instrument, fires six beams. The three pairs are fired at a rate of 10,000 pulses per second.

Every second, ATLAS bounces 300 trillion green photons off Earth's surface. By measuring the time it takes each pulse to return, ATLAS can precisely measure the height and slope of the surface below -- in this instance, the height of Antarctica's ice sheet.

"We were all waiting with bated breath for the lasers to turn on and to see those first photons return," Donya Douglas-Bradshaw, the project manager for ICESat-2's ATLAS instrument, said in a news release. "Seeing everything work together in concert is incredibly exciting. There are a lot of moving parts and this is the demonstration that it's all working together."

Though IceSat-2 and its laser instrument can and will measure a variety of surfaces, including ocean waves and forest canopies, its main focus is ice -- mainly sea ice.

"We're losing more and more sea ice every year and we don't know why," Tom Wagner, ICESat-2 program scientist, told UPI last month.

IceSat-2 launched in mid-September. Before its science mission could commence, NASA engineers had to allow time for any potential contaminants picked up during the launch and flight to dissipate. Scientists also had to test the probe's instrument and communication system.

Now, IceSat-2 has returned its first data. Mission scientists were excited to confirm the accuracy of the data gathered with the first laser pulse.

"It was awesome," said Tom Neumann, ICESat-2 deputy project scientist. "Having it in space, and not just simulating data on the ground, is amazing. This is real light that went from ATLAS to Earth and back again."

The probe's scientific mission is still a half-month away. Scientists and engineers still need to ensure the laser instrument is properly calibrated -- that its laser is angled properly and the pulses are firing at the correct frequency.

"It will take a couple of additional weeks, but about one month after launch we'll hopefully start getting back some excellent science-quality data," Neumann said