Space geodetic techniques such as the GNSS, VLBI, SLR/LLR, and DORIS have reached a high quality level with respect to the classical applications in geodesy such as precise determination of station positions and of the Earth orientation parameters.Two research activities at GFZ are presented which go beyond these standard applications.The goal of the first project briefly described here (called D-VLBI) is the realization of frame ties between the dynamic reference frames of space probes like satellites, spacecrafts, the Moon or other planetary bodies, the kinematically defined International Celestial Reference Frame (ICRF) consisting of precise coordinates of extragalactic radio sources (radio galaxies or quasars), and the International Terrestrial Reference Frame (ITRF) realized on Earth.This can be done best by using the differential Very Long Baseline Interferometry (method, connecting a space probe to a close-by quasar by alternately observing signals of those two sources.In the research project D-VLBI a general concept for future applications of VLBI measurements to space probes will be developed.The benefit of observing GNSS satellites by VLBI radio telescopes is investigated by simulations.It is well known that the troposphere is the main error source of VLBI.It was found that changing the observation interval and entering additional observations to quasars in order to increase the sky coverage for each station are proper means to reach the expected accuracies of a few millimeters 3D station root mean square (rms).In addition we briefly review the innovative GNSS remote sensing activities at GFZ.Ground and space based (radio occultation) atmosphere sounding was pioneered by GFZ scientists since several years and reached an operational application level.Best example for this development is the routine use of atmospheric GNSS data products to improve regional and global weather forecasts of the leading weather centres, which was started in 2006.The GNSS atmospheric data are also widely used by a large, international user community of geodesists, atmospheric scientists and climate researchers.The importance of the related GNSS data products will increase during the next years with the upcoming new GNSS systems, the larger GNSS ground networks and the continuously increasing number of GNSS occultation receivers at Low Earth Orbiting satellites.In the recent years the international research focus in GNSS remote sensing was more and more focused on the GNSS reflectometry, which complements the atmosphere sounding techniques.Geophysical parameters of water, ice and land surfaces can be derived using the GNSS reflectometry.Several successful ground and airborne experiments demonstrated already the large potential of this innovative space geodetic technique for Earth Observation.Recently also first dedicated satellite based experiments are in preparation.However more international research work and cooperation is necessary to develop the GNSS reflectometry onto a similar application level as the GNSS atmosphere sounding.