Aquarius SAC-D Spacecraft Prepared for June 9 Launch

In a little over two months, the United States and Argentina will be launching a joint mission aimed at analyzing saltwater in the world's oceans. The mission will provide climate researchers and other scientists with more data on Earth's natural cycles, and their influence on the world.

The Satélite de Aplicaciones Científicas (SAC)-D was developed by the Comisión Nacional de Actividades Espaciales (CONAE), which is the Argentinian space agency. NASA is contributing the Aquarius instrument on the new satellite.

Just recently, the instrument made its way to the Vandenberg Air Force Base (VAFB), in California, after traveling half the world during its design, production, integration and testing phases.

Its components were created at a range of facilities owned by NASA. Some of them were refined even further at a science and technology center in Bariloche, Argentina. After the instrument was complete, it was tested in Brazil in a special space simulator.

Now, it finally made its way to the VAFB, where it will be integrated on the spacecraft bus. All the other systems, including navigation, propulsion and flight control, will be installed on SAC-D as well.

The Greenbelt, Maryland-based Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL), in Pasadena, California, were the two main NASA centers that collaborated to make the Aquarius instrument suite a reality.

One of its main components is the microwave radiometer instrument. This is what will allow the satellite to conduct measurements of ocean salinity from its orbital vantage point.

“The radiometer is the most accurate and stable radiometer built for sensing of Earth from space. It's a one-of-a-kind instrument,” says GSFC microwave communications expert Shannon Rodriguez-Sanabria.

“The ocean is essentially Earth's thermostat. It stores most of the heat, and what we need to understand is how do changes in salinity affect the 3D circulation of the ocean,” adds the GSFC Aquarius Ground System and Mission Operations manager, Gene Feldman.

Another critical component of Aquarius is the scatterometer microwave radar sensor instrument, which was built at the JPL. What it does is it transmits data on wind speed to the GSFC radiometer.

The latter can then compensate for the effect that winds have on ocean circulation, which enables it to figure out the role that salinity alone plays in this.