Aquarius makes first ocean salt measurements

Sep 02, 2011 By Alan Buis and Steve Cole
Artist's concept of the Aquarius/SAC-D spacecraft, a collaboration between NASA and Argentina's space agency, with participation from Brazil, Canada, France and Italy. Aquarius, the NASA-built primary instrument on the spacecraft, will take NASA's first space-based measurements of ocean surface salinity, a key missing variable in satellite observations of Earth that links ocean circulation, the global balance of freshwater and climate. The mission is scheduled to launch in June. Credit: NASA

(PhysOrg.com) -- NASA's Aquarius instrument has successfully completed its commissioning phase and is now "tasting" the saltiness of Earth's ocean surface, making measurements from its perch in near-polar orbit.

"This marks the end of the long to design, build and launch this mission, and the start of a new journey of ," said Aquarius Principal Investigator Gary Lagerloef of Earth & Space Research, Seattle. "Scientists from around the world are ready and waiting to study this important new satellite measurement for ocean and climate research."

The Aquarius/SAC-D (Satélite de Aplicaciones Científicas) observatory, a collaboration between and Argentina's space agency, Comisión Nacional de Actividades Espaciales (CONAE), launched from California's Vandenberg Air Force Base on June 10 aboard a United Launch Alliance Delta II rocket and was placed in its proper initial orbit. Ground controllers at the SAC-D Mission Operations Center in Teófilo Tabanera Space Center in Cordoba, Argentina, then began a complete in-orbit checkout of all SAC-D spacecraft systems.

With all observatory systems confirmed to be healthy, SAC-D spacecraft commissioning activities were completed on July 24. The spacecraft's propulsion system then underwent a series of tests, and preliminary orbit adjustments were performed in preparation for turning on the observatory's eight science instruments.

Aquarius will make NASA's first space observations of the salinity, or concentration of salt, at the , a key variable in satellite studies of Earth. Variations in salinity influence the ocean's deep circulation, outline the path freshwater takes around our planet and help drive Earth's climate.

On Aug. 14, the Aquarius Instrument Flight Operations Team, together with the SAC-D Mission Flight Operations Team, began powering up the Aquarius instrument, and successfully completed deployment of the Aquarius antenna on Aug. 17. The team then began sequentially powering on the instrument's subsystems. On Aug. 20, the Aquarius radiometer, which collects the brightness temperature data from which salinity measurements are derived, was powered on for the first time in space and transmitted its first science data back to Earth, which were analyzed and found to be as expected. On Aug. 21, the team began powering on Aquarius' radar scatterometer, which corrects for the effects of ocean roughness on the radiometer readings. Commissioning of Aquarius was completed and regular data collection began on Aug. 24.

The Aquarius science team will spend the coming months analyzing and calibrating the and releasing preliminary data.

With the Aquarius instrument commissioning now complete, the SAC-D Instruments Flight Operations Teams, together with the SAC-D Mission Flight Operations Team in Argentina, are now engaged in commissioning the other seven SAC-D instruments. Once all the observatory instruments are commissioned, a maneuver will be conducted to place /SAC-D in its final orbit, 408 miles (657 kilometers) above Earth.

Explore further: Cassini: Return to Rhea

More information: For more information about Aquarius/SAC-D, visit: www.nasa.gov/aquarius and www.conae.gov.ar/eng/principal.html .

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User comments : 2

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Bob_Kob
not rated yet Sep 02, 2011
aaaaaaand any guess we will see an increase in salinity no doubt caused by global warming and not due to the fact that we have no accurate measurements beforehand.
Jeddy_Mctedder
1 / 5 (1) Sep 02, 2011
spot on.
HOWEVER, though we are all cynical about the reason these studies are funded ( with a biased fear motivating the money spent) i think we can all agree climate science is cool. and is usually genuine science ( this project seems to be genuine collection of novel data ) .

sometimes you hear about non-studies dressed up as science and it's gross. this isn't

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