Analysis of the long-term evolution of the scd1 satellite temperatures
- Paper number
IAC-06-C2.6.10
- Author
Dr. Issamu Muraoka, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil
- Coauthor
Ms. Andreia Sorice, Technological Institute of Aeronautics - ITA/CTA, Brazil
- Coauthor
Dr. Ezio Castejon Garcia, Instituto Tecnológico de Aeronáutica – ITA – IEM, Brazil
- Year
2006
- Abstract
This paper investigates the possible causes of long-term temperature deviation on SCD1 satellite (Satélite de Coleta de Dados) by analyzing the evolution of its thermal behavior along 13 years in orbit. SCD1 is the first satellite designed and constructed in Brazil. It was launched successfully in 1993, and is still in operation. The thermal control was achieved by passive means using coatings and conductive paths appropriately chosen to keep the satellite temperatures in the specified levels. A mathematical model was developed to simulate the SCD1 thermal behavior in orbit and it was used as a tool to define all thermal design variables. The temperatures of thirty SCD1 components have been monitored and recorded in the Satellite Tracking and Control Center since the launching. An analysis done at the beginning of the mission indicated that all temperatures were in the predicted ranges. Along the years the battery, that is the most thermal sensitive equipment, presented a temperature increase reaching its upper limit. There are many possible causes for that including the degradation of the battery, which could change its internal heat dissipation, and the degradation of the satellite external coating due to exposition to the space environment. This last one changes the coating optical properties and consequently changes the overall satellite temperatures. The methodology to investigate the causes of the temperature deviation consists in performing the following steps: (i) to obtain the temperature data on dates at interval of six months, from 1993 to 2005; (ii) for each date, to compare the measured temperatures with the values obtained by the simulation with the original mathematical model; (iii) for each date, to adjust the variables, that represent the candidate causes of temperature deviation, in the mathematical model in order to obtain a good correlation between the theoretical and measured temperatures; (iv) gathering the results of the previous step, to obtain the evolution of adjusted variables along the studied period. The results of this investigation can be useful for the ongoing satellite development, particularly to be aware of the possible causes of the long-term temperature deviation and to consider them more accurately in the design analysis.
- Abstract document