Salt-Seeking Spacecraft Arrives at Launch Site

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
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PASADENA, CALIF. 91109 TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

Steve Cole 202-358-0918
NASA Headquarters, Washington
Stephen.e.cole@nasa.gov

News release: 2011-103 March 31, 2011

Salt-Seeking Spacecraft Arrives at Launch Site
NASA Instrument Will Measure Ocean Surface Salinity

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2011-103&cid=release_2011-103

PASADENA, Calif. – An international spacecraft that will take NASA's first space-based
measurements of ocean surface salinity has arrived at its launch site at Vandenberg Air Force Base in
California. The Aquarius/SAC-D mission will provide scientists with a key missing variable in satellite
observations of Earth that links ocean circulation, the global balance of freshwater and climate.

The Aquarius/SAC-D spacecraft left Sáo José dos Campos, Brazil, on March 29. Following final
tests, the spacecraft will be attached to a Delta II rocket for a June 9 launch.

The mission is a collaboration between NASA and Argentina's space agency, Comisión Nacional de
Actividades Espaciales (CONAE), with participation from Brazil, Canada, France and Italy.
Aquarius, the NASA-built primary instrument on CONAE's SAC-D spacecraft, will map global
changes in the concentration of dissolved salt at the ocean surface. Measuring salinity is important to
understanding how changes in rainfall, evaporation and the melting or freezing of ice influence ocean
circulation and are linked to climate changes. The three-year mission will provide new insights into
how variations in ocean surface salinity relate to these fundamental climate processes.

"Just as salt is essential to life as we know it, salinity is crucial to Earth's climate system," said
Aquarius Principal Investigator Gary Lagerloef of Earth and Space Research in Seattle. "Very small
changes in salinity can have large-scale effects on ocean circulation and the way the ocean moderates
our climate. These changes are linked to the movement of water between the ocean, atmosphere and
cryosphere."

Aquarius will greatly enhance the quantity of ocean salinity measurements that have been collected
from ships, buoys and floats.

"When combined with data from other sensors that measure sea level, ocean color, temperature,
winds, rainfall and evaporation, Aquarius' continuous, global salinity data will give scientists a much
clearer picture of how the ocean works, how it is linked to climate and how it may respond to climate
change," Lagerloef said.

Precise salinity measurements from Aquarius will reveal changes in patterns of global precipitation
and evaporation, and show how these affect ocean circulation. Studies from Aquarius eventually will
improve computer models used to forecast future climate conditions, including short-term climate
events such as El Niño and La Niña.

"The mission continues a long and successful partnership between NASA and CONAE, and it will
provide a new type of ocean observation for ocean and climate studies," said Amit Sen, Aquarius
project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Aquarius will measure ocean surface salinity by sensing thermal microwave emissions from the water's
surface with a radiometer. When other environmental factors are equal, these emissions indicate how
salty the surface water is. Because salinity levels in the open ocean vary by only about five parts per
thousand, Aquarius employs new technologies to detect changes in salinity as small as about two
parts per 10,000, equivalent to about one-eighth of a teaspoon of salt in a gallon of water.

Flying in a 657-kilometer (408-mile) high, polar orbit, Aquarius/SAC-D will map the global ocean
once every seven days. Its measurements will be merged to yield monthly estimates of ocean surface
salinity with a spatial resolution of 150 kilometers (93 miles). The data will reveal how salinity
changes over time and from one part of the ocean to another.

Aquarius is a NASA Earth System Science Pathfinder Program mission. The Aquarius instrument was
jointly built by JPL and NASA's Goddard Space Flight Center in Greenbelt, Md. NASA's Launch
Services Program at the Kennedy Space Center in Florida is managing the launch. JPL will manage
Aquarius through the mission's commissioning phase and archive mission data. Goddard will manage
the mission's operations phase and process Aquarius science data.

CONAE is providing the SAC-D spacecraft, an optical camera, a thermal camera in collaboration
with Canada, a microwave radiometer, sensors developed by various Argentine institutions, and the
mission operations center in Argentina. France and Italy also are contributing instruments.

For more information on Aquarius, visit: http://aquarius.nasa.gov and
http://www.conae.gov.ar/eng/principal.html .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

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