The Joint Center for Satellite Data Assimilation (JCSDA) was established by NASA, NOAA and the DoD in 2001. The goal of the JCSDA is to accelerate the use of observations from satellites in operational numerical analysis and prediction models for weather and climate forecasts and for increasing the accuracy of climate data sets. Advanced instruments of current and planned satellite missions, do and will increasingly provide large volumes of data related to atmospheric, oceanic, and land surface state. These data will exhibit accuracies and spatial, spectral and temporal resolutions never before achieved. The JCSDA will ensure that the maximum benefit from investment in space is realised from the advanced global observing system. It will accelerate the use of satellite data from both operational and experimental spacecraft for weather and climate related activities. To this end the advancement of data assimilation science by the JCSDA has included advanced radiative transfer studies, including extensions to the JCSDA community radiative transfer model for AIRS and the incorporation of snow and sea ice emissivity models for improving the use of microwave sounding data over high latitudes. It has also included assessment of the impact of current instruments on operational NWP, and preparation for the use of future instruments such as METOP IASI/AMSU/HSB, DMSP SSMIS, COSMIC/GPS and EOS-AQUA AMSR-E . Improved data assimilation techniques have also been developed within the JCSDA aided by the unification of the NCEP global data assimilation analysis system and that of the NASA Global Modeling and Assimilation Office (GMAO). Eighteen other research projects are also being supported by the JCSDA to develop the state of-the-art satellite data assimilation system. The work undertaken by the JCSDA (in particular data assimilation, data impact, OSSE, THORPEX and network design studies) also represent key activities of GEOSS. The recent advances in work undertaken by the JCSDA will be presented at this meeting.