The QuikSCAT was quite revolutionary at the time, having launched in June of 1999 as the replacement to the NASA Scatterometer (NSCAT). The SeaWinds on QuikSCAT was the first scanning scatterometer launched by NASA (the NSCAT was a KU-band fan-beam system). It was herald as quite the engineering feat at the time, and ended up tripling the expected design life (which was 2-3 years, but the rotating antenna ended up failing after 10 years).
While there are three alternatives still active that can be comparable to the QuikSCAT, none are quite as refined. The ASCAT satellite can measure global wind speed and direction twice a day, however it only covers 60% of the area the QuikSCAT did and leaves a 720 km gap between the two parallel swaths of 550 km that the satellite sees. The OSCAT instrument has the same 1800 km swath as the QuikSCAT but has issues with rain contamination and has ½ the resolution of the QuikSCAT (which had a 12.5 km resolution versus the 25 km resolution on the OSCAT). The third option is the Windsat instrument aboard the Coriolis satellite. While this also measures wind speed and direction (using a different technique then the QuikSCAT), the winds data are unreliable in and around tropical storms.
Much like the QuikSCAT (which was designed and built in a month), the ISS-RapidScat was designed quite cleverly. It will be attached to the International Space Station and will reuse hardware originally designed as test parts for the previous QuickSCAT satellite. Thus, the cost of the ISS-RapidScat will be the most cost effective to date (the cost of development was nearly 1/10th of the traditional costs for such a satellite). The ISS-RapidScat will be NASA’s first scientific Earth-observing instrument specifically designed and developed to operate from the exterior of the space station. This will put the ISS-RapidScat into a unique orbit compared to any other scatterometer or wind-measuring instrument currently in orbit. With an altitude that varies from 233-270 miles, the ISS-RapidScat will provide the first near-global direct observations of how oceans winds vary over the course of the day and greatly influence the ability to track the formation, strengthening, and movement of tropical cyclones.
The most important part; the ability to repair the instrument if hardware failures occur will be quite convenient (unlike the other scatterometers).
Components of NASA's International Space Station-RapidScat instrument rest side by side in Kennedy Space Center's Space Station Processing Facility. ISS-RapidScat will measure Earth's ocean surface wind speed and direction from the station, data that will be used for weather and marine forecasting. Credit: NASA/Dimitri Gerondidakis
References:
http://www.wunderground.com/blog/JeffMa ... or-proenza
http://www.jpl.nasa.gov/news/news.php?release=2014-151
http://winds.jpl.nasa.gov/missions/quikscat/
