SAC-D

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SAC-D
Aquarius SAC-D satellite.png
Artist's impression of SAC-D in orbit
Mission type Earth science
Operator CONAE
NASA
COSPAR ID 2011-024A
SATCAT № 37673
Website www.conae.gov.ar/eng/satelites/sac-d.html
Mission duration 5 years
Spacecraft properties
Manufacturer INVAP
INPE/LIT[disambiguation needed]
Start of mission
Launch date June 10, 2011, 14:20:13 (2011-06-10UTC14:20:13) UTC
Rocket Delta II 7320-10C
Launch site Vandenberg SLC-2W
Contractor ULA
End of mission
Last contact June 17, 2015 (2015-06-18)
Orbital parameters
Reference system Geocentric
Regime Sun-synchronous
Perigee 659 kilometers (409 mi)[1]
Apogee 661 kilometers (411 mi)[1]
Inclination 98.01 degrees[1]
Period 97.81 minutes[1]
Epoch 25 January 2015, 00:27:17 UTC[1]
Instruments
Aquarius

SAC-D (Spanish: Satelite de Aplicaciones Cientificas-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 launched on June 10, 2011.[2] It carries seven instruments to study the environment, and a technology demonstration experiment.[3] Its primary instrument, Aquarius, was built by and is operated by the United States National Aeronautics and Space Administration. SAC-D is operated by CONAE, the Argentine space agency. The satellite was planned to operate for five years; however the Aquarius instrument was only planned to operate for three.[4] The satellite failed on 8 June 2015.[5]The Aquarius instrument successfully achieved its science objectives and completed its primary three-year mission in November 2014.

Launch[edit]

Launch of the Aquarius/SAC-D observatory.

NASA launched Aquarius/SAC-D from Vandenberg Air Force Base, California, on June 10, 2011. [6] A Delta II 7320-10 was used as the launch vehicle, taking off from Space Launch Complex 2W at Vandenberg Air Force Base. NASA was responsible for providing launch services,[7] which were subcontracted to United Launch Alliance. The launch was delayed from May 2010 because development of the spacecraft was taking longer than expected.[8]

Description[edit]

The Aquarius/Satélite de Aplicaciones Científicas (SAC)-D satellite observatory, was an international collaboration between NASA and Argentina’s space agency, Comisión Nacional de Actividades Espaciales (CONAE), with participation from Brazil, Canada, France and Italy.

Aquarius' mission was to demonstrate that accurate measurements of salinity could be made from space. Aquarius was the first mission to combine use of passive (radiometer) and active (radar) measurements at L-band.

Salinity information is important to increasing the understanding of two parts of Earth’s climate system: the water cycle and ocean circulation.

The Aquarius instrument was jointly built by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. JPL managed Aquarius through the mission’s commissioning phase and archives mission data. Goddard managed the mission’s operations phase and processes Aquarius science data. CONAE provided 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 contributed instruments.[9]

Accomplishments[edit]

The 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[9].

Failure[edit]

On June 8, 2015 preliminary indications are that an onboard hardware component called a Remote Terminal Unit (RTU) shut down, causing the loss of onboard power regulation and spacecraft attitude stabilization.[9]

Instruments[edit]

Name Operator Purpose
Aquarius United States NASA Ocean salinity research
CARMEN I France CNES Two experiments: SODAD will study particles and debris in space, ICARE will study cosmic radiation and its effects on electronics
DCS Argentina CONAE Collection of data provided by platforms on Earth. Compatible with Argos System
HSC Argentina CONAE Imaging of aurorae, fires, and lights
MWR Argentina CONAE Radiometry
NIRST Argentina CONAE
Canada CSA
Infrared imagery, determination of sea temperatures
ROSA Italy ASI Measurement of temperature and humidity in the atmosphere
TDP Argentina CONAE Technology demonstration involving GPS navigation and inertial guidance[3]

See also[edit]

References[edit]

  1. ^ a b c d e "SAC-D (AQUARIUS) Satellite details 2011-024A NORAD 37673". N2YO. 25 January 2015. Retrieved 25 January 2015. 
  2. ^ "Aquarius". Nasa. Retrieved 25 July 2013. 
  3. ^ a b "Aquarius/SAC-D Instruments". CONAE. Retrieved 2010-01-06. 
  4. ^ "Vandenberg delays launch of Aquarius satellite". KSBY6. Retrieved 25 July 2013. 
  5. ^ Stephen Clark (17 June 2015). "International ocean research observatory fails in orbit". spaceflightnow.com. Retrieved 18 June 2015. 
  6. ^ "NASA's 'Age of Aquarius' Dawns With California Launch". NASA GSFC. Retrieved 2011-06-10. 
  7. ^ "Aquarius / SAC-D Satellite Mission". Earth & Space Research. Retrieved 2010-01-06. 
  8. ^ Clark, Stephen (2009-12-26). "Ocean-watching satellite facing delays in Argentina". Spaceflight Now. Retrieved 2010-01-06. 
  9. ^ a b c "International Spacecraft Carrying NASA’s Aquarius Ends Operations". Retrieved 2015-06-18. 

External links[edit]