The FORMOSAT-3 mission, also known as COSMIC, Constellation Observing System for Meteorology, Ionosphere, and Climate, is the third major project of the FORMOSAT series implemented by National Space Organization (NSPO) in Taiwan. The mission is jointly developed by Taiwan's NSPO, the US's UCAR in collaboration with NSF, USAF, NOAA, NASA, JPL and NRL. The FORMOSAT-3 consisting of six LEO satellites is the world's first demonstration of GPS radio occultation (RO) near real-time operational constellation mission representing a revolution in atmospheric sounding from space, with precise, accurate, and all-weather global observations useful for weather, climate, and space weather research and operations. The FORMOSAT-3 has processed over 1800 good atmospheric sounding profiles per day, which exceeds the number of worldwide radiosondes launched per day. Since the successful launch in April 2006, FORMOSAT-3 has provided over 1 million GPS RO soundings. The goal of the follow-on mission is to transfer the mission from research to real-time operational, which will steadily provide about 9000 GPS RO soundings per day. The planning mission is complementary to the current mission with a new constellation of 12 to 18 satellites. Currently, the atmospheric radio soundings data are assimilated into the Numerical Weather Prediction (NWP) models for weather prediction and typhoon/hurricane forecast. The data assimilations into the operational systems have shown positive impact on weather prediction to global and national weather centers, such as Denmark Meteorological Institute (DMI), European Centre for Medium- Range Weather Forecasts (ECMWF), Institut D'Estudis Espacials de Catalunya (IEEC), United Kingdom Met Office (UKMO), National Environmental Satellite, Data, and Information Service (NESDIS), Joint Center for Satellite Data Assimilation (JCSDA), and many other weather forecast centers in Japan, Korea, China, India, and Taiwan. This paper describes the state-of-the-art achievements and the results of current mission; the follow-on mission overview and planning status.