GetWiki

}}SAC-D (, meaning Satellite for Scientific Applications-D), also known as Aquarius after its primary instrument, is an Argentine Earth science satellite built by INVAP and operated by CONAE. SAC-D was launched from Vandenberg Air Force Base on 10 June 2011, with a planned mission life of five years. Due to a power system failure, the mission was ended on 8 June 2015.NEWS,weblink International ocean research observatory fails in orbit, Spaceflight Now, Stephen, Clark, 17 June 2015, 18 June 2015,

Description

SAC-D was an international collaboration between the space agencies of Argentina and the United States, CONAE and NASA, with participation from Brazil (INPE), Canada (CSA), France (CNES) and Italy (ASI).NEWS,weblink Farewell Aquarius as SAC-D spacecraft concludes its mission, NASA Spaceflight, William, Graham, Chris, Bergin, 17 June 2015, 18 December 2015, It carried five Earth observation instruments (NASA, CONAE, CSA, ASI), two space science instruments (CNES), a data collection instrument (CONAE), and a technology demonstration system (CONAE).WEB,weblink Aquarius/SAC-D onboard instruments, CONAE, 18 December 2015, WEB,weblink Aquarius/SAC-D: Sea Surface Salinity from Space, NASA/University of Maine, Nicole, Miklus, Annette, deCharon, 2010, 18 December 2015, The spacecraft's main instrument, Aquarius, was built by NASA's Jet Propulsion Laboratory and Goddard Space Flight Center. It collected data from 25 August 2011 to 7 June 2015, exceeding its intended three year primary mission.NEWS,weblink PI Announcement to Science Team and Broader Science Community, University of Maine, Gary, Lagerloef, Sandra, Torrusio, 18 June 2015, 18 December 2015, Aquarius' mission was to demonstrate that accurate measurements of salinity could be made from space, and was the first spaceborne instrument to use both passive radiometers and active radar in the L band. By measuring ocean salinity, scientists are better able to understand the Earth's water cycle and ocean circulation. Project scientists later derived a method of pulling soil moisture data from Aquarius' radiometer.

Launch

NASA launched SAC-D from Vandenberg Air Force Base's Space Launch Complex 2W aboard a Delta II 7320-10C on 10 June 2011 at 14:20:13 UTC.WEB,weblink NASA's 'Age of Aquarius' Dawns With California Launch, NASA, Alan, Buis, Steve, Cole, 10 June 2011, 10 June 2011, The launch was delayed from May 2010 because development of the spacecraft was taking longer than expected.NEWS,weblink Ocean-watching satellite facing delays in Argentina, Spaceflight Now, Stephen, Clark, 26 December 2009, 6 January 2010,

Accomplishments

The Aquarius instrument's surface salinity measurements contributed to a better understanding of ocean dynamics and advancing climate and ocean models, both from season to season and year to year. The models still are improving El Niño prediction. Aquarius global salinity maps show how freshwater plumes coming from the mouth of large rivers and the precipitation and evaporation over the oceans affect the salinity structure of the ocean.“The Aquarius sensor collected three years and nine months of valuable data. It was truly a pioneering effort to determine how accurately we could measure ocean salinity from space and for the first time study large and small-scale interactions of the global water cycle.” Aquarius principal investigator Gary Lagerloef of Earth & Space Research, Seattle.Aquarius provided information into the natural exchange of freshwater between the ocean, atmosphere and sea ice, which influences ocean circulation, weather and climate.Data from Aquarius showed how extreme floods affect the seas and how low-salinity river plumes affect hurricane intensity. Aquarius data was important to the Salinity Processes in the Upper Ocean Regional Study (SPURS), a year-long international field study of the oceanographic processes that sustain the maximum surface salinities in the central subtropical North Atlantic, and influence global ocean circulation.The Aquarius instrument successfully achieved its science objectives and completed its primary three-year mission in November 2014.

Failure of spacecraft

On 7 June 2015 at 12:53:17 UTC, telemetry indicated a failure of the spacecraft's Remote Terminal Unit (RTU), causing loss of onboard power regulation and attitude stabilization. While efforts were made to recover the spacecraft, the mission was declared over on 8 June.WEB,weblink International Spacecraft Carrying NASA's Aquarius Instrument Ends Operations, NASA, Dwayne, Brown, Rani, Gran, Alan, Buis, 17 June 2015, 18 December 2015,

Instruments{| class"wikitable"

! Abbreviation !! Name !! Operator !! PurposeAquarius (SAC-D instrument)>Aquarius NASA Ocean salinity researchComisión Nacional de Actividades Espaciales>CONAE RadiometryCanadian Space Agency>CSA Infrared imagery, determination of sea temperatures| Imaging of aurorae, fires, and lights| Collection of data provided by platforms on Earth. Compatible with Argos systemGlobal Positioning System>GPS navigation and inertial guidanceItalian Space Agency>ASI Measurement of temperature and humidity in the atmosphereCNES >| Part of CARMEN-1 mission; study of cosmic radiation and its effects on electronicsCNES >| Part of CARMEN-1 mission; study of particles and debris in space

See also

• 2011 in spaceflight
• Jason-1
• Ocean Surface Topography Mission
• Aquarius (SAC-D instrument)

References

{{reflist}}

External links

{{Commons category|SAC-D}}

• SAC-D website by CONAE
• SAC-D website by INVAP
• Aquarius website by NASA
• Aquarius website by the University of Maine

{{Argentina space program}}{{Orbital launches in 2011}}