Accurately measuring the world’s freshwater reserves is becoming a reality with the launch of NASA’s Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, the follow on from GRACE 2002, featuring world-first technology developed in Australia.
ANU Professor Daniel Shaddock has developed satellite technology that uses lasers to measure the world’s water reserves from space.
“It measures something that’s really important; the presence of water – whether that’s frozen form or liquid form – across the entire globe at once. And that’s something you can only do from space,” Shaddock told ABC Online.
“Any large body of water will generate gravity and that gravity can be picked up by GRACE.”
GRACE detects small changes in gravity caused by large masses of water on Earth, which then causes a pair of satellites to speed up or slow down, Shaddock said. The laser device measures these changes in speed.
“In the case of the Laser Ranging Interferometer, we can pick up changes in the separation of the spacecraft by ten nanometres. That’s ten billionths of a metre – about the diameter of a virus,” he said.
“Once the laser links have been acquired I’ll certainly rest a little easier – that’s really the biggest challenge facing GRACE.
“If that doesn’t work we won’t get any data back, and if it does work, I’m much more confident that we’ll get some really valuable insights.”
Shaddock said that while the launch was a nerve-wracking moment, he is very excited about receiving the satellite data.
“It was a little bit surreal. So many years of your life working on something – it was hard to believe it was actually happening and finally launching,” he said.
“It was very exciting when it finally went up and nothing blew up. And the most exciting part is still yet to come.”