Description: The purpose of this project is to develop and demonstrate a communications system capable of operation at extreme temperatures and pressures in hostile and corrosive environments such as found on the surface of the planet Venus. Although already explored by various orbiters and short-lived atmospheric probes and landers, Venus retains many secrets pertaining to its formation and evolution and also the ability to further probe and investigate Venus' surface is of significant scientific value. However the measurement of data and collection of information in an extreme environment is of limited use or value unless the data and information can be sent out of the environment. This proposed project will address vital communication needs of the future in situ exploration of Venus and atmospheric probes for giant planets. The technology to be employed in the proposed extreme environment communications system is based on a proven class of electronic devices called solid state vacuum devices (SSVD^TMs). S-band (~ 2 to 4 GHz) power amplifiers and transmitters along with S-band receivers will be designed and built in this proposed SBIR project to enable essential and critical communications between vehicles and probes located on Venus' surface and systems in orbit around Venus.