A variety of Observing System Simulation Experiments (OSSEs) aimed at assessing the impact of future observing systems have been performed in the Joint Center for Satellite Data Assimilation. The experiments and done using the NCEP Global Forecasting System and are based on the T-511 Nature Run provided by the European Centre for Medium Range Weather Prediction. So far, the most extensive set of experiments has been aimed at a notional US space-based wind lidar, roughly based on the GWOS concept developed by NASA in response to the NRC Decadal Survey. These experiments have been carried out at different horizontal resolutions, for extended periods of time, and have included various potential configurations of the GWOS mission. However, the OSSE test environment developed for the lidar experiments is now also used to study the impact of sensors from other systems such as JPSS and DWSS. We will provide an overview of the current status of the JCSDA OSSE test environment, of the experimental results obtained with it, and of our plans for its future development and use.