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Aqua Image Courtesy of NASA
NASA's Aqua satellite, launched in May 2002, is designed to study the earth's physical processes with an emphasis on the water cycle. The Aqua mission is part of NASA's Earth Observing System (EOS). The development and operation of Aqua and its instruments are an international collaboration.
| Instrument | Sponsor | Developer | Spectral Resolution | Geophysical parameters |
| Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) | Japan Aerospace Exploration Agency (JAXA, Japan) | Japan Aerospace Exploration Agency (JAXA, Japan) | 12 channels at six discrete frequencies from 6.9 GHz to 89 GHz | Precipitation rate, water vapor, surface moisture content, sea ice extent, snow extent |
| Atmospheric Infrared Sounder (AIRS) | NASA Jet Propulsion Laboratory (JPL) | BAE Systems | More than 2,300 spectral channels ranging from 0.4 µm to 15.4 µm | Atmospheric temperature and humidity, land and sea surface temperatures, cloud, radioative energy flux |
| Advanced Microwave Sounding Unit (AMSU) | NASA Goddard Space Flight Center (GSFC) | Aerojet | 15 channels ranging from 50 GHz to 90 GHz | Atmospheric temperature and humidity |
| Clouds and the Earth's Radiant Energy System (CERES) | NASA Langley Reseach Center (LaRC) | TRW Space and Electronics Group | Cross-track and azimuthal scanners with three channels per scanner | Radiative energy flux |
| Humidity Sounder for Brazil (HSB) | Brazilian National Institute for Space Studies | Matra Marconi Space | Five channels ranging from 150 MHz to 183 MHz | Atmospheric humidity |
| Moderate Resolution Imaging Spectroradiometer (MODIS) | NASA Goddard Space Flight Center | Raytheon (Santa Barbara Remote Sensing) | 36 channels ranging from 0.4 µm to 14 µm | Cloud, radioative energy flux, aerosols, land cover and land use change, vegetation dynamics, land surface temperature, sea surface temperature, ocean color, snow cover, atmospheric temperature and humidity, sea ice |
The primary science objective of the Earth Observing System (EOS) Aqua mission is the study of Earth's interrelated physical processes with an emphasis on the water cycle. Primary variables of interest include: ocean evaporation, atmospheric water vapor, clouds, terrestrial snow, land ice, sea ice, sea surface temperature, precipitation, and soil moisture. Additional variables include: radiative energy fluxes, atmospheric temperatures, humidities, aerosols, land vegetation cover, and ocean productivity.
Aqua is part of NASA's Earth Science Enterprise, a long-term research effort dedicated to understanding and protecting Earth. Aqua is a joint project between the United States, Japan, and Brazil.
Aqua flies in a sun-synchronous polar orbit with global coverage. Ground tracks repeat every 16 days or every 233 orbit revolutions. Path numbers are calculated based on the longitude of the orbital ascending node. With 233 paths, path 1 corresponds to 295.4 degrees east longitude. Since each orbit covers 16 grid lines, the path numbers increment by 16 for each orbit (NASA 2000).
See Aqua Maneuvers for satellite maneuvers and orbital anomalies that may potentially affect the quality of data for specific dates.
Aqua command and telemetry communications are sent to the EOS Polar Ground Stations (EGPSs) in Svalbard and Alaska. These stations relay real-time S-band and X-band science and satellite housekeeping data between Aqua and the Level 0 Processing Facility at NASA GSFC. A third EPGS site, the McMurdo ground station, provides contingency S-band and X-band support. Finally, a ground station in Wallops, Virginia, provides real-time S-band command and telemetry support for Aqua. The EOS Mission Support network (ESMn) provides communication services for all Aqua data including spacecraft command, telemetry, and orbit (engineering and science) data. The ESMn also provides communication services among the EOS mission-critical elements of the ground system (NASA 2000).
The S-band telemetry system communicates real-time housekeeping, critical health and safety, diagnostic memory dump data, and backup recorder dumps of housekeeping data to the ground systems. Aqua requires routine space network support for tracking data and clock correlation. Coherent, two-way tracking support is required four to six times per day with a duration of approximately ten minutes for each contact. Periodic orbital maneuvers will be required to maintain the orbit parameters (NASA 2000).
The EOS Ground System (EGS) provides the Aqua mission with communication, flight operations, science data processing, data archival, and data distribution.
The EOS Operations Center (EOC) at GSFC provides the following services for command and control of the spacecraft and instruments (NASA 2000):
The EOS Data and Operations System (EDOS) provides real-time forward and return link data services from the EOC to the White Sands Complex, and Wallops and EPGS ground stations. EDOS receives raw science data, performs level 0 processing of the data, and forwards it to the appropriate Distributed Active Archive Centers (DAACs). EDOS also archives level 0 science data for the life of the Aqua mission, plus three years (NASA 2000).
Aqua crosses the equator at 1:30 p.m. local time in an ascending node.
The following acronyms are used in this document:
NASA. 2000. EOS Aqua (PM) Ground System Requirements Document. GSFC #422-11-19-05. Greenbelt, MD: NASA Goddard Space Flight Center.
