The S3 VLBI data record and playback system and future Space VLBI missions

The use of “orbiting radio observatories” to conduct VLBI observations on Earth-to-Space and Space-to-Space baselines is the only means by which the fundamental limitations on the angular resolution of images afforded by the technique of VLBI which result from the finite physical dimensions of the Earth and the opacity of the atmosphere at millimeter and sub-millimeter wavelengths may be circumvented. For continuum observations, the loss of correlated flux on long baselines as well as other technical considerations generate a requirement for very wide bandwidth VLBI systems to support future Space VLBI missions. This report presents a brief description of the 1024 – 2048 Mb/sec (1 – 2 Gb/sec) “S3” VLBI system under development at the Space Geodynamics Laboratory (SGL) of the Center for Research in Earth and Space Technology (CRESTech).