The FORMOSAT-3 mission, also known as COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) consisting of six satellites is an experimental “Science Mission” for demonstrating the usefulness of Radio Occultation (RO) in operational numerical weather prediction, climate monitoring, and space weather forecasting. The retrieved RO weather data (currently ~ 1,800 + per day on the average) by the six satellites were assimilated into the Numerical Weather Prediction (NWP) model by many major weather forecast centers and research institutes for real-time weather predictions and cyclone/typhoon/hurricane forecasts. The success of the FORMOSAT-3/COSMIC mission expected to operate through 2011 has initiated a new age for operational GPS RO soundings. The World Meteorological Organization (WMO) has recommended continuing RO observations operationally and the scientific community urges the continuation of the current mission and the planning for a follow-on operational mission. The planned follow-on mission will meet the “operational” system with required redundancy and robustness with a new constellation of 7(=6+1), 12 or 18 satellites at different orbital planes. The follow-on mission needs to establish international standards so that future RO missions deployed by any country can be used together for operations and research. The primary payload of the satellite will be equipped with the GNSS RO receiver and collects more soundings per receiver by adding Galileo/GLONASS (optional) tracking capability and higher density of profiles which are more useful for global and mesoscale models, and also severe weather forecasting. Taiwan has taken an active role in constellation operations of the current RO mission. Taiwan continues pursuing international cooperation of the follow-on mission for scientific research and applications that meet the need of the global Radio Occultation data for Meteorology Beyond 2011. In this paper, we will present the results of current FORMOSAT-3 / COSMIC mission and its follow-on mission planning overview.