The NASA QuikSCAT (Quick Scatterometer) was an Earth observation satellite carrying the SeaWinds scatterometer. Its primary mission was to measure the surface wind speed and direct over the ice-free global oceans via its effect on water waves. Observations from QuikSCAT had a wide array of applications, and contributed to climatological studies, weather forecasting, meteorology, oceanographic research, marine safety, commercial fishing, tracking large icebergs, and studies of land and sea ice, among others. This SeaWinds scatterometer is referred to as the QuikSCAT scatterometer to distinguish it from the nearly identical SeaWinds scatterometer flown on the ADEOS-2 satellite. Mission description QuikSCAT was launched on 19 June 1999 with an initial 3-year mission requirement. QuikSCAT was a "quick recovery" mission replacing the NASA Scatterometer (NSCAT), which failed prematurely in June 1997 after just 9.5 months in operation. QuikSCAT, however, far exceeded these design expectations and continued to operate for over a decade before a bearing failure on its antenna motor ended QuikSCAT's capabilities to determine useful surface wind information on 23 November 2009. The QuikSCAT geophysical data record spans from 19 July 1999 to 21 November 2009. While the dish could not rotate after this date, its radar capabilities remained fully intact. It continued operating in this mode until full mission termination on October 2, 2018. Data from this mode of the mission was used to improve the accuracy of other satellite surface wind datasets by inter-calibrating other Ku-band scatterometers. QuikSCAT measured winds in measurement swaths 1,800 km wide centered on the satellite ground track with no nadir gap, such as occurs with fan-beam scatterometers such as NSCAT. Because of its wide swath and lack of in-swath gaps, QuikSCAT was able to collect at least one vector wind measurement over 93% of the World's Oceans each day. This improved significantly over the 77% coverage provided by NSCAT. Each day, QuikSCAT recorded over 400,000 measurements of wind speed and direction. This is hundreds of times more surface wind measurements than are collected routinely from ships and buoys. QuikSCAT provided measurements of the wind speed and direction referenced to 10 meters above the sea surface at a spatial resolution of 25 km. Wind information cannot be retrieved within 15–30 km of coastlines or in the presence of sea ice. Precipitation generally degrades the wind measurement accuracy, although useful wind and rain information can still be obtained in mid-latitude and tropical cyclones for monitoring purposes. In