QuikSCAT mission is intended to record sea-surface wind speed and direction data under all weather and cloud conditions over Earth's oceans. QuikSCAT was initiated as a "quick recovery" mission to help reduce the ocean-wind vector data gap created by the loss of the NASA Scatterometer (NSCAT) on the Japanese Advanced Earth Observing Satellite (ADEOS), which ceased functioning when ADEOS failed on June 30, 1997. QuikSCAT was launched from Vandenberg Air Force Base, Calif., aboard a Titan II vehicle, reducing the data gap by about one-half.
The QuikSCAT ocean-viewing satellite captured this image of Hurricane Dora in the eastern tropical Pacific Ocean on August 10, 1999 as it was blowing at speeds of nearly 40 meters per second (90 miles per hour). The image shows surface wind speed (colored background) and wind direction (arrows) in the vicinity of the hurricane, which was centered near 14.5 degrees north latitude and 117.8 degrees west longitude.
QuikSCAT operates in a near polar orbit. It flies in a circular orbit at an altitude of approximately 800 km (500 miles) above Earth's surface. It completes a full orbit in about 101 minutes, which translates to a little more than 14 orbits per day.
SeaWinds is the main instrument on the QuikSCAT satellite. SeaWinds is an active radar scatterometer. This scatterometer operates by transmitting high-frequency microwave pulses to the ocean surface and measuring the echoed radar pulses bounced back to the satellite. The scatterometer estimates wind speed and direction over the Earth's oceans at 10 m above the surface of the water. The instrument collects data over ocean, land, and ice in a continuous, 1,800-kilometer-wide band, making approximately 400,000 measurements and covering 90% of Earth's surface in one day. QuikSCAT can acquire hundreds of times more observations of surface wind velocity each day than can ships and buoys, and can provide continuous, accurate and high-resolution measurements of both wind speeds and direction regardless of weather conditions. This data is vital for global climate research, operational weather forecasting, and storm warning.
QuikSCAT, launched in June 1999, remained fully operational until November 2009 when the primary instrument (SeaWinds) antenna stopped rotating due to a mechanical failure of the antenna spin mechanism. During its nominal mission, QuikSCAT was a primary data source for science applications and studies involving climate models, interactions between the atmosphere and ocean, and weather/climate phenomena such as hurricanes and El Niño. Although SeaWinds radar performance was not affected by the spin mechanism failure, the scatterometer now tracks an operational data path swath significantly reduced from its original capability. However, these data are continuing to provide an accurate and reliable transfer standard for cross-calibration of other ocean vector winds sensors, and for establishing the measurement stability needed for continuity with future scatterometer missions. Agreements are now in place to allow the QuikSCAT team access to measurements from the Indian Space Research Organization (ISRO) Oceansat-2 scatterometer known as OSCAT, which launched in September 2009. The NASA/ISRO partnership is a long-term collaboration between the two agencies, and provides for a direct cross-calibration of QuikSCAT’s SeaWinds scatterometer with the ISRO OSCAT to assist in the production of an ongoing ocean vector winds climate series. Continuing the QuikSCAT mission remains vital to NASA’s science objectives and societal needs, and ongoing QuikSCAT observations will help satisfy the requirement for contiguous overlap and cross-calibration of ocean scatterometer climate data records.