Flight 2 version of in‐orbit test transponder (IOTT2) for on‐board regenerative satellites

Abstract

AbstractThis paper presents the design and realization of regenerative satellite on‐board bypass test equipment. Furthermore, two particular examples of an in‐orbit test transponder (IOTT) are discussed in detail. The IOTT1, developed for the first 30/20 GHz ITALSAT satellite (F1), was launched in January of 1991. IOTT1 has been a useful tool during satellite assembly, integration and pre‐launch tests. IOTT1 was successfully used to fully characterize the multibeam ITALSAT satellite in orbit.In general, the IOTT functions to bypass the demodulator, the baseband switchboard and the modulator of the multibeam package of the ITALSAT spacecraft payload, providing the ability to fully characterize the satellite's transponders using well‐established IOT test techniques.This paper describes and compares the design, fabrication and test of both ITALSAT in‐orbit test RF bypass transponders (IOTT1 and IOTT2) mounted on board the ITALSAT multibeam spacecraft, (F1) and (F2), respectively. The IOTT1 contains the first MMIC circuitry ever launched into space on a communications satellite. The improved IOTT2, fabricated for the second 30/20 GHz ITALSAT satellite (F2), is schedule for launch in early 1996.These fully space‐qualified designs incorporate COMSAT Laboratories' designed and fabricated MMIC Ku‐band amplifiers, lightweight waveguide Ku‐band channel filters and electronic power conditioner (EPC) and combined IOTT telemetry/command (T&C) circuitry.