ITALSAT F2 and its EMS payload for mobile communications

ITALSAT is the Italian doniestic cotnniunication satellite system designed to provide digital conununication capacity over Italy. The first ITALSAT spacecraft (FI) was successfully launched in January '91. Its primary objective was the in orbit evaluation of the advanced technologies and the architecture suitable for a domestic digital coniniunication system. The purpose of the second spacecraft (F2) is to make the communication system fully operational. The ITA LSA T digital coinniunication system for fixed services is based on an innovative Regenerative Multibeatn payload and on a more conventional Transparent Payload. Both operate at Ka band (20/30 GHz). Fl has, also, a propagation package on-board which allows experiments at 20 GHz (inainly for correlation with the existing data) and at 40 and 50 GHz which are the next frequency bands still to be explored for future comtnunication systenis. The article provides a description of the main Mission parameters. A review of the requirerrients that ESA specified for the EMS Payload, including the frequency plan and the Service areas is given. A firnctional description of the payload architecture is presented together with the main tradeofls that have lead to the specific design. The rnain aspects of the technology which warranted particular attention cluring the cleveloptrrent phase of the systetti are adressed.