US: NASA launched the Earth-science satellite SAC-D/Aquarius from Vandenberg Air Force Base in California, US. Its Aquarius instrument can look for salt within Earth’s oceans. The US and Argentina are the prime countries involved with the mission, along with Brazil, Canada, France, and Italy.
The SAC-D is the spacecraft, called Satélite de Aplicaciones Científicas (Satellite for Scientific Applications-D). It was the work of Argentina’s CONAE. The primary instrument on board SAC-D is Aquarius. SAC-D also contains seven other instruments for study of the Earth. The other instruments on board include:
– CARMEN (France, CNES): Will study particles and debris in space, and cosmic radiation and its effects on electronics.
– DCS (Argentina, CONAE): Will collect data as part of the Argos System.
– HSC (Argentina, CONAE): Will image aurorae, fires, and lights.
– MWR (Argentina, CONAE): Will provide radiometric data.
– NIRST (Argentina, CONAE): Will use infrared imagery to determine sea temperatures.
– ROSA (Italy, ASI): Will measure temperature and humidity of Earth’s atmosphere.
– TDP (Argentina, CONAE): Will test new technologies involving GPS navigation and inertial guidance.
NASA is in charge of the Aquarius instrument, which will measure the saltiness of Earth’s oceans. The Aquarius instrument will help to learn more about the global water cycle and help to improve climate forecasts. According to NASA’s press statement, “Aquarius will map the global open ocean once every seven days for at least three years with a resolution of 93 miles (150 kilometres). The maps will show how ocean surface salinity changes each month, season and year. Scientists expect to release preliminary salinity maps later this year.”
And, “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. “