SAC-D ( es, Satélite de Aplicaciones Científicas-D, meaning ''Satellite for Scientific Applications-D''), also known as Aquarius after its primary instrument, is an
Argentine
Argentines (mistakenly translated Argentineans in the past; in Spanish (masculine) or (feminine)) are people identified with the country of Argentina. This connection may be residential, legal, historical or cultural. For most Argentines, s ...
Earth science
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
built by
INVAP
INVAP S.E. is an Argentine company that provides design, integration, construction and delivery of equipment, plants and devices. The company operates in North America, Europe, Asia Pacific, Latin America, the Middle East and Africa, and delivers p ...
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.
Description
SAC-D was an international collaboration between the space agencies of Argentina and the United States,
CONAE and
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
, with participation from Brazil (
INPE), Canada (
CSA
CSA may refer to:
Arts and media
* Canadian Screen Awards, annual awards given by the Academy of Canadian Cinema & Television
* Commission on Superhuman Activities, a fictional American government agency in Marvel Comics
* Crime Syndicate of Amer ...
), France (
CNES
The (CNES; French: ''Centre national d'études spatiales'') is the French government space agency (administratively, a "public administration with industrial and commercial purpose"). Its headquarters are located in central Paris and it is und ...
) and Italy (
ASI).
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).
The spacecraft's main instrument,
Aquarius
Aquarius may refer to:
Astrology
* Aquarius (astrology), an astrological sign
* Age of Aquarius, a time period in the cycle of astrological ages
Astronomy
* Aquarius (constellation)
* Aquarius in Chinese astronomy
Arts and entertainme ...
, 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.
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
The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of frequencies in the radio spectrum from 1 to 2 gigahertz (GHz). This is at the top end of the ultra high frequency (UHF) band, at the lower en ...
.
By measuring ocean salinity, scientists are better able to understand the Earth's
water cycle
The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly cons ...
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 Vandenberg may refer to:
* Vandenberg (surname), including a list of people with the name
* USS General Harry Taylor (AP-145), USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in K ...
's
Space Launch Complex 2W aboard a
Delta II
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...
7320-10C on 10 June 2011 at 14:20:13 UTC.
The launch was delayed from May 2010 because development of the spacecraft was taking longer than expected.
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.
Instruments
See also
*
2011 in spaceflight
*
Jason-1
Jason-1 was a satellite altimeter oceanography mission. It sought to monitor global ocean circulation, study the ties between the ocean and the atmosphere, improve global climate forecasts and predictions, and monitor events such as El Niño ...
*
Ocean Surface Topography Mission
OSTM/Jason-2, or Ocean Surface Topography Mission/Jason-2 satellite, was an international Earth observation satellite altimeter joint mission for sea surface height measurements between NASA and CNES. It was the third satellite in a series st ...
*
Aquarius (SAC-D instrument)
Aquarius was a NASA instrument aboard the Argentine SAC-D spacecraft. Its mission was to measure global sea surface salinity to better predict future climate conditions.
Aquarius was shipped to Argentina on June 1, 2009 to be mounted in the ...
References
External links
SAC-D websiteby CONAE
by INVAP
Aquarius websiteby NASA
Aquarius websiteby the University of Maine
{{Orbital launches in 2011
Spacecraft launched in 2011
Satellites of Argentina
Earth observation satellites