Theongoing progress ofthetechnology usingsignals transmitted fromsatellites toground stations orendusers requires a development ofallthedevices whichare involved inthegeneration, processing andtransmission of theinthemeantime verycomplex signals. A veryclear generated signal should notbemadeworseduring the amplification. Traveling WaveTubes(TWT)forsatellite application arebasedonawellknownphysical theory. THALESELECTRONDEVICES(TED)demonstrated that thetubeisstill averyflexible andreliable amplifier withalarge space proven heritage whichcanbeusednot onlyforstandard CW operation butalsoforthe transmission ofverysensible data like modulated signals in theL-bandfornavigation systems - successfully demonstrated bythefirst In-Orbit tests ofGiove-A Galileo Satellite.