JPL launches Aquarius

JPL scientists are celebrating the successful Friday morning launch of a satellite that will measure ocean salinity levels in an effort to track changing ocean currents and, by extension, increase understanding of global climate change.

The Earth-orbiting Aquarius SAC-D satellite, a joint effort of JPL and Argentina’s space agency, was launched into space at 7:20 a.m. from Vandenberg Air Force Base aboard a Delta-2 rocket.

“Everything went flawlessly,” said JPL Aquarius Project Manager Amit Sen. “About an hour after launch, we detected separation from the rocket and unfurled our solar panels, which give us the energy we need to operate while in orbit.”

The Aquarius sea salinity measurement instrument was built by Sen’s team at JPL in La Cañada Flintridge and is housed in the Argentine-built SAC (Satelite de Aplicaciones Cientificas) satellite chassis. Aquarius will begin scanning Earth’s oceans in about 25 days, providing consistent weekly measurements from various points around the world over the next three years, said Sen.

The satellite measures salinity by using radio receivers to detect the electrical conductivity of water, which varies depending on how much salt is dissolved in it.

In addition to helping track and eventually better predict El Niño and other phenomena driven by ocean currents, Aquarius salinity data will be used to test global warming models and theories, explained JPL’s Yi Chao, project scientist for the Aquarius mission.

Ocean salinity levels relate to water density and temperature and are affected by evaporation, precipitation and melting glaciers and ice caps.

“By monitoring changes in salinity, you can estimate how the global water cycle is changing. Scientists believe that in a warming climate, you’re going to see speeding up of ocean cycles,” said Chao. “Having continued global measurements each week over three years, we can use the data to systematically verify those climate models and test different hypotheses.”

Although several previous NASA missions have studied temperature, depth and other ocean conditions, Aquarius represents the agency’s first attempt to measure sea salinity from space.

Salinity levels are difficult to measure by boat. Many areas, especially in and around the South Pole, have never been tested, said Chao.