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ABSTRACT. µSAT-1 "VÍCTOR" IS A 32-KG, 350*350*450 MM, 3-AXIS CONTROLLED, EARTH IMAGING MICROSATELLITE, INTENDED FOR DEVELOPMENT, QUALIFICATION AND TESTING OF LOW-COST SPACE TECHNOLOGIES; PROGRAM BEGAN IN SEPTEMBER, 1992, BEING LAUNCHED AUGUST 29TH, 1996 INTO AN ELLIPTIC, 245*1200 KM, 62OINCLINATION ORBIT, BY A MOLNYA LAUNCHER, AS A SECONDARY PAYLOAD. IT BECAME THE FIRST ARGENTINE-MADE SATELLITE, PERFORMING ACCORDING TO MISSION REQUIREMENTS UP TO DATE, ALMOST THREE YEARS LATER.
THIS PAPER PRESENTS A STUDY ABOUT THE THERMAL BEHAVIOUR OF THE SATELLITE DURING ITS LIFE, AS SEEN THROUGH FLIGHT TELEMETRY DATA. AS MOST MICROSATELLITES, "VÍCTOR" PRESENTS A PARTICULAR FLIGHT PROFILE, WHICH CONSISTS MAINLY IN A RANDOM, FREE - ATTITUDE MOVEMENT DURING MOST OF FLIGHT TIME, BEING THREE-AXIS CONTROLLED ONLY WHEN IT IS AT EARTH STATION RANGE, CONDITION THAT OCCURS TWICE OR, AT MOST, FOUR TIMES A DAY, FOR PERIODS OF TEN TO FIFTEEN MINUTES EACH ONE. MOREOVER, TEMPERATURE DATA ARE TAKEN ONLY ON EARTH STATION REQUIREMENT, NOT IN A CONTINOUS SAMPLING MODE.
DUE TO THESE OPERATING FEATURES, A STOCHASTIC ANALYSIS OF FLIGHT DATA WAS PREFERRED, WHICH PROVED TO BE MORE USEFUL THAN THE DETERMINISTIC TEMPERATURE ASSESMENT NORMALLY PERFORMED IN BIGGER, WELL-KNOWN ATTITUDE SATELLITES. RESULTS OBTAINED DURING OPERATION FROM NOVEMBER 1996 TO JULY 1998 ARE PRESENTED, AS WELL AS CONSIDERATIONS ABOUT THE STOCHASTIC ANALYSIS PERFORMED AND CONCLUSSIONS, WHICH REPRESENTED GREAT AID IN THE THERMAL DESIGN OF µSAT-2, THE SECOND SATELLITE OF THE SERIES, TO BE LAUNCHED DURING LAST QUARTER OF 1999.
KEYWORDS: MICROSATELLITE, THERMAL CONTROL, STOCHASTIC ANALYSIS |
