NASA's 'Age of Aquarius' dawned Friday with the launch of an international satellite carrying the agency-built Aquarius instrument that will measure the saltiness of Earth's oceans to advance our understanding of the global water cycle and improve climate forecasts.

The Aquarius/SAC-D observatory rocketed into space from Vandenberg Air Force Base in California atop a United Launch Alliance Delta II rocket at 7:20:13 a.m. PDT (10:20:13 a.m. EDT). Less than 57 minutes later, the observatory separated from the rocket's second stage and began activation procedures, establishing communications with ground controllers and unfurling its solar arrays.

Initial telemetry reports show the observatory is in excellent health. The SAC-D (Satelite de Aplicaciones Cientificas) observatory is a collaboration between NASA and Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE).

"Aquarius is a critical component of our Earth sciences work, and part of the next generation of space-based instruments that will take our knowledge of our home planet to new heights," said NASA Deputy Administrator Lori Garver. "The innovative scientists and engineers who contributed to this mission are part of the talented team that will help America win the future and make a positive impact across the globe."

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

"Data from this mission will advance our understanding of the ocean and prediction of the global water cycle," said Michael Freilich, director of NASA's Earth Science Division in the Science Mission Directorate at agency headquarters in Washington. "This mission demonstrates the power of international collaboration and accurate spaceborne measurements for science and societal benefit. This would not be possible without the sustained cooperation of NASA, CONAE and our other partners."

In addition to Aquarius, the observatory carries seven instruments that will monitor natural hazards and collect a broad range of environmental data. Other mission partners include Brazil, Canada, France and Italy.

"This mission is the most outstanding project in the history of scientific and technological cooperation between Argentina and the United States," said CONAE Executive and Technical Director Conrado Varotto. "Information from the mission will have significant benefits for humankind."

Aquarius will map the global open ocean once every seven days for at least three years with a resolution of 93 miles (150 kilometers). The maps will show how ocean surface salinity changes each month, season and year. Scientists expect to release preliminary salinity maps later this year.

Aquarius will measure salinity by sensing thermal microwave emissions from the water's surface with three microwave instruments called radiometers. When other environmental factors are equal, these emissions indicate the saltiness of surface water. A microwave radar scatterometer instrument will measure ocean waves that affect the precision of the salinity measurement. Because salinity levels in the open ocean vary by only about five parts per thousand, Aquarius will be able to detect changes as small as approximately two parts per 10,000, equivalent to about one-eighth of a teaspoon of salt in a gallon of water.

During the next 25 days, the Aquarius/SAC-D service platform will be tested and maneuvered into its final operational, near-polar orbit 408 miles (657 kilometers) above Earth. Science operations will begin after the observatory's instruments are checked out. This commissioning phase may last up to 65 days.

Team Vandenberg launches Delta II rocket
Team Vandenberg launched a Delta II rocket carrying the Aquarius/SAC-D (Satelite de Aplicaciones Cientificas) observatory from Space Launch Complex-2 here at 7:20 a.m. PDT.

Col. Richard Boltz, 30th Space Wing commander, was the launch decision authority.

"Team Vandenberg performed brilliantly once again in ensuring safe and successful launch operations," said Colonel Boltz. "We wish our mission partners at NASA well as they begin their important work with Aquarius."

The Aquarius/SAC-D observatory is a collaboration between NASA and Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE).

Aquarius is the NASA-built primary instrument on the SAC-D spacecraft, built by CONAE. Aquarius will map global changes in salinity - the concentration of dissolved salt - at the ocean surface.

Salinity is a key measurement for understanding how changes in rainfall, evaporation, and the melting or freezing of ice influence ocean circulation and are linked to variations in Earth's climate. According to NASA officials, the three-year mission will provide new insights into how variations in ocean surface salinity relate to these fundamental climate processes.

United Launch Alliance Successfully Delivers Aquarius Mission to Orbit
A United Launch Alliance Delta II rocket carrying the Aquarius/SAC-D observatory for NASA and the Space Agency of Argentina lifted off from Space Launch Complex-2W here at 7:20 a.m. PDT today. This is ULA's sixth launch of the year and marked the 40th Delta II launch from Vandenberg Air Force Base.

"ULA is extremely proud to be a part of the Aquarius/SAC-D mission, which will offer scientists NASA's first global observations of ocean surface salinity from space to better understand ocean circulation and the resulting effects on our climate," said Jim Sponnick, ULA vice president, Mission Operations. "Today's successful launch is the culmination of years of hard work by NASA and the ULA launch team, along with our many other mission partners."

This mission was launched aboard a Delta II 7320-10 configuration vehicle featuring an ULA first stage booster powered by a Pratt and Whitney Rocketdyne RS-27A main engine and three Alliant Techsystems (ATK) strap-on solid rocket motors. An Aerojet AJ10-118K engine powered the second stage. The payload was encased by a 10-foot-diameter composite payload fairing.

"The Delta II vehicle continues to offer excellence, best value and continuous improvement to our customers," said Sponnick. "The reliability of this vehicle is a testament to the dedicated employees that ensure mission success is the top priority for each and every launch."

NASA's Aquarius, the primary instrument on the SAC-D observatory, will provide unprecedented global maps of ocean surface salinity to better understand the links between ocean circulation, the global cycling of freshwater and climate.

ULA's next launch is the Delta IV GPS IIF-2 mission for the United States Air Force mission currently scheduled for July 14, 2011 from Space Launch Complex-37 at Cape Canaveral Air Force Station, Fla.

ULA program management, engineering, test and mission support functions are headquartered in Denver, Colo. Manufacturing, assembly and integration operations are located at Decatur, Ala., Harlingen, Texas, San Diego, Calif. Launch operations are located at Cape Canaveral AFS, Fla., and Vandenberg AFB, Calif.