Aquarius / SAC-D Satellite Mission


The ESR Aquarius Team


Aquarius/SAC-D Satellite artist conception from orbit over southern Patagonia.
The background image is based on SeaWiFS data.

Gary Lagerloef

Principal Investigator (PI)
Phone: +1 (206) 726-0501
Fax: +1 (206) 726-0524
 
David Carey
Validation System Manager
Phone: +1 (206) 726-0501
Fax: +1 (206) 726-0524
 
Hsun-Ying Kao
Research Analysis
Phone: +1 (206) 726-0501
Fax: +1 (206) 726-0524
 
Camisa Carlson
PI Aquarius Administrator
Phone: +1 (206) 726-0501
Fax: +1 (206) 726-0524


Aquarius / SAC-D Satellite Mission Overview

The Aquarius mission is one of two new Earth System Science Pathfinder small-satellite program missions confirmed by NASA in 2005. Each mission performs a first-of-a-kind exploratory measurement that will help answer fundamental questions about how our planet works and how it may change in the future.

The innovative Aquarius satellite launched successfully from Vandenberg Air Force Base in California on June 10, 2011 aboard a United Launch Alliance Delta II rocket. It is the first satellite mission specifically designed to provide monthly global measurements of how sea water salinity varies at the ocean surface, which is a key to studying the links between ocean circulation and global water cycles. Variations in ocean surface salinity are a key area of scientific uncertainty. Salinity variations modify the interaction between ocean circulation and the global water cycle, which in turn affects the ocean’s capacity to store and transport heat and regulate Earth's climate. The Aquarius Mission seeks to determine how the ocean responds to the combined effects of evaporation, precipitation, ice melt and river runoff on seasonal and inter-annual time scales, and their impact on the global distribution and availability of fresh water. Sea surface salinity, along with sea surface temperature, determines the sea surface density. This controls the formation of water masses in the ocean and regulates the 3-dimensional ocean circulation. Recent technological advances have provided the ability to examine these processes using remote sensing tools via satellite, and will further understanding of how climate variations induce changes in the global ocean circulation and how our oceans respond to climate change and the water cycle.

More information about the Aquarius Mission can be found on the Aquarius SAC/D Mission Home Page. To track Aquarius “real-time” , view Where Is Aquarius?. Download the Aquarius Education & Public Outreach Resources document for links to the iPhone App, Mission Overview and many other audio and visual educational resources for this important mission.

The Aquarius / SAC-D Mission is successfully streaming real-time salinity data and providing scientists with NASA’s first global map of salinity. The first image and accompanying data and mission history are available on JPL's Photojournal, the NASA Aquarius page and the official NASA press release; Aquarius Yields NASA's First Global Map of Ocean. Aquarius is the lead story on This Week@NASA. For more information, please see Aquarius Image Gallery and Animation.


Aquarius Team Partners

Aquarius is an international partnership mission. The key members and their roles are outlined below:




Satellite Development


PI Gary Lagerloef next to the full scale SAC-D structural model, 27 Feb 08.

The Aquarius mission was developed in an international partnership with Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE), which has successfully developed three consecutive science application satellites in cooperation with NASA. Numerous university, corporate, government and international institutions are also involved in the Aquarius mission. For the joint mission, Argentina provided the SAC-D spacecraft and additional science instruments and conducts the mission operations. NASA developed and built the Aquarius salinity sensor and provided the rocket launch at Vandenberg Air Force Base in California on June 10, 2011 at 7:20M PDT. NASA's Jet Propulsion Laboratory in Pasadena, California, managed the Aquarius Mission development for NASA's Earth System Science Pathfinder program, and NASA's Goddard Spaceflight Center in Greenbelt, Maryland, now manages the mission after launch.




Satellite Instruments

Aquarius Instruments (NASA)
  • Passive Salinity Sensor L-Band Radiometer operating at 1.4 GHz
  • Active Surface Roughness Sensor L-Band Scatterometer operating at 1.2 GHz, using real aperture and a 2.5 meter composite reflector antenna

CONAE Instruments:
  • Microwave Radiometer (MWR)
  • Infra-red Camera (NIRST)
  • High Sensitivity Camera (HSC)
  • Data Collection System (DCS)
  • Technological Demonstration Package (TDP)

Third Party Instruments
  • ROSA (ASI)
  • SODAD (CNES)






Aquarius Launch Video



Aquarius Satellite Animations




Mission Concept

Instrument Mode: Active/Passive L-band, Push-broom measurement approach using 3-beam, offset antenna.

Orbit: 657 km, sun synchronous @ 6 pm, ascending node

Observatory: CONAE contributes SAC-D (Satelite de Aplicaciones Cientificas) Service Platform and Ground Station.

Attitude & Orbit Control: Three axis stabilized, nadir pointing; maneuvering thrusters.

Observatory Dimensions (launch config): 2,7m (diameter) and 4,5 m

Communications: S Band Up and Downlink, X Band Data Downlink

Operational Life: 3 years (Aquarius); 5 years (S/P and SAC-D Instruments)

Launch Date: June 10, 2011

Launch Vehicle: Boeing Delta II 7320-10 Launch Vehicle

Launch Site: Vandenberg Air Force Base (VAFB), California, USA

Science Products: 7-day, Monthly and Yearly Global Maps

Data Availability: Through PO.DAAC (NASA / JPL)


Mission Design and Measurement Approach


The Aquarius/SAC-D mission concept. The satellite is in a polar sun-synchronous orbit crossing the equator at 6pm (ascending) and 6am (descending) local time. The Aquarius sensor views continually away from the sun to avoid signal contamination from solar L-band energy flux. The three beams vary in width and incidence angle to form a 390 km wide ground swath. The orbit has an exact repeat ground track every seven days, with 390 km track spacing at the equator, ensuring complete global coverage of the swath. Salinity data calibration and validation will be based on available in situ surface measurements by ships, buoys and Argo floats.



Aquarius Validation Data System

The Aquarius Validation Data System (AVDS) obtains and process surface measurements from the data centers of several ocean observation programs (Argo GOSUD, TAO, ...) as a means of delivering surface calibration data to the Aquarius data processing center. Liaisons are maintained with various observation programs in order to acquire near surface data on a daily basis. The data are quality controlled and edited if necessary and provided in a uniform data format.


The two primary data sources are:

TAO/TRITON Internet GUI
http://www.pmel.noaa.gov/tao/data_deliv/

US GODAE - ARGO Float data
http://www.usgodae.org/argo/argo.html


The following data sources will be added at a later time:

Coriolis Global Ocean Profiles (including ARGO)
http://www.coriolis.eu.org/cdc/DataSelection/cdcDataSelections.asp

GOSUD ftp
ftp://ftp.ifremer.fr/ifremer/gosud

GOSUD Internet GUI
http://www.coriolis.eu.org/cdc/GosudSelection/cdcGosudSelections.asp

US GTSPP - Global Ocean Profiles
http://www.nodc.noaa.gov/GTSPP/gtspp-home.html



Aquarius Outreach and Education

The Aquarius / SAC-D Satellite Mission has a dedicated educational and public outreach (EPO) effort which is led by Annette deCharon, Senior Science Educator and Aquarius EPO Manager. Please visit the Aquarius outreach website, http://aquarius.gsfc.nasa.gov/education.html, to learn more.




Aquarius In The News