{"title":"Design concepts and performance of NASA X-band transponder (DST) for deep space spacecraft applications","authors":"N. Mysoor, J. Perret, A. Kermode","doi":"10.1109/AERO.1991.154526","DOIUrl":"https://doi.org/10.1109/AERO.1991.154526","url":null,"abstract":"The authors summarize the design concepts and measured performance characteristics of an X-breadboard deep space transponder (DST) for future spacecraft applications, with the first use scheduled for the CRAF and Cassini missions (1995 and 1996). The DST consists of a double conversion, superheterodyne, automatic phase tracking receiver, and an X-band exciter to drive redundant downlink power amplifiers. The receiver acquires and coherently phase-tracks the modulated or unmodulated X-band uplink carrier signal. The exciter phase, modulates the X-band downlink signal with composite telemetry and ranging signals. The receiver-measured tracking threshold, automatic gain control, static phase error, and phase jitter characteristics of the breadboard DST are in good agreement with the expected performance. The measured results show a receiver tracking threshold of -158 dBm and a dynamic signal range of 88 dB.<<ETX>>","PeriodicalId":158617,"journal":{"name":"1991 IEEE Aerospace Applications Conference Digest","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132328495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Galileo spacecraft autonomous attitude determination using a V-slit star scanner","authors":"S. Mobasser, S. Lin","doi":"10.1109/AERO.1991.154529","DOIUrl":"https://doi.org/10.1109/AERO.1991.154529","url":null,"abstract":"Absolute attitude determination and the rotor spin rate of the Galileo spacecraft are derived solely from a two-axis star scanner, (SS) that is sensitive (outside the Jovian magnetosphere) to at least 200 brightest stars. With the 200-star sensitivity, the SS always provides at least three stars for attitude determination anywhere in the spacecraft orbit. Because the SS must function in the intense Jupiter radiation environment, which consists primarily of high-energy electrons and photons, the Galileo SS is designed with radiation hardness as a prime objective. The Galileo SS is described together with an entirely autonomous attitude determination algorithm. The SS analytical model is also presented. The selection process for the model's critical parameters which are used by the attitude determination algorithm is explained. Post launch operation of the attitude determination algorithm is discussed and actual flight data are presented.<<ETX>>","PeriodicalId":158617,"journal":{"name":"1991 IEEE Aerospace Applications Conference Digest","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115164898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}