47th International Conference on Environmental Systems ICES-2017-265 16-20 July 2017, Charleston, South Carolina Lessons Learned Analysis in Thermal Tests for CubeSats in Brazil George Favale e Feranandes1a,b, Roy Soler Stevenson Chisabas2a Osvaldo Donizete3 a, Carlos Frajuca4b, Daniel Fernando Cantor5 aInstituto Nacional de Pesquisas Espaciais - INPE, Laboratório de Integração e Testes – LIT, Av. dos Astronautas, 1758, 12227-010, São José dos Campos, SP, Brazil. bInstituto Federal de Educação, Ciência e Tecnologia de São Paulo – IFSP, Rua Pedro Vicente, 625, Canindé, 01109-010, São Paulo, SP, Brazil. Satellite projects include many mandatory and needed parameters and requirements for their proper functioning during their mission. Although there are many orbital dynamics similarities among satellites, dedicated analyses are carried out with the purpose of analyzing all system responses, when they are exposed to the spatial environment. Inserted in a satellite project, or any other kind of component for this application, are the thermal control projects and analyses. Taking into account all those pieces of information, all thermal test specifications are generated and carefully dimensioned. The CubeSats, which figure as experimental spatial systems designed, developed and built by universities and research institutes, with components not 100% qualified for these purposes, should also undergo this dedicated thermal analysis to generate more specific test requirements for each mission and contribute to the increase of the system reliability. However, in most of the cases, that is not what happens. The Integration and Testing Laboratory - LIT, at the National Institute for Space Research - INPE, in São José dos Campos - SP, Brazil, recognized for its expertise in all the assembly, integration and test cycle for satellites and space components and using its experience acquired in over 25 years working in this field intends, in this article, to discuss all lessons learned while performing CubeSats’ space simulation tests, in qualification and acceptance levels. We will discuss topics related to instrumentation, test specification, setup and lack of qualified human resources in projects, among other relevant themes related to thermal tests in CubeSats and, in the end, we will give our final evaluation. Keywords: Thermal Tests, CubeSat, Instrumentation, Setup, Qualification Level, Acceptance Level Nomenclature AEB = Brazilian Space Agency AESP-14 = Turma AeroESPacial 14 anti-ESD = anti- Electrostatic discharge Atm = Atmospheric CBERS = China-Brazil Earth Resources Satellite 1 Mechanical Engineer, Integration and Test Laboratory – LIT, [email protected] 2 Aeronautical Engineer, Integration and Test Laboratory – LIT, [email protected] 3 Mechanical Technician, Integration and Test Laboratory – LIT, [email protected] 4 Mechanical Engineering Professor, IFSP, [email protected] 5 Research Engineer, [email protected] CONAE = Comisión Nacional de Actividades Espaciales CRS = Southern Regional Center FCFM = Faculty of Physical and Mathematical Sciences FM = Flight Model GAUSS = Group of Astrodynamics for the Use of Space Systems GSE = Ground Support Equipment H-IIB = H II Transfer Vehicle B HSB = Humidity Sounder for Brazil HTV = H II Transfer Vehicle IGGF = International Geomagnetic Reference Field INPE = National Institute for Space Research ISIS = Innovative Solutions In Space ISS = International Space Station. ITA = Technological Institute of Aeronautics LEO = Low Earth orbit LIT = Integration and Testing Laboratory mBar = miliBar NASA = National Aeronautics and Space Administration QM = Qualification Model SAC-D = Scientific Application Satellites-D SATEC = Technological Satellite SCD = Data Collector Satellite SERPENS = Sistema Espacial para Realização de Pesquisas e Experimentos com Nanossatélites SPEL = Space and Planetary Exploration Laboratory SUCHAI = Satellite of the University of Chile for Aerospace Investigation TCC = Thermal Climatic Chamber TCT = Thermal Cycling Test TuPOD = TubeSat Deployer TVC = Thermal Vacuum Chamber TVT = Thermal Vacuum Test UFABC = Federal University of ABC UFMG = Federal University of Minas Gerais UFRGS = Federal University of Rio Grande do Sul UFSC = Federal University of Santa Catarina UFSM = Federal University of Santa Maria UHF = Ultra High Frequency UNB = Brasília University VHF = Very High Frequency I. Introduction FTER more than 50 years since the first space probes were launched, the satellites have developed and Aincreased in size and complexity. This increase has also required the development and specialization of the professionals involved, because at each new project, new payloads, special monitoring and research systems are needed. Over time, there has also been an increase in the demand for Earth’s monitoring information, for weather forecasting, and even for new communication and espionage systems, for example. These initial projects were developed by governmental research institutes that saw satellites as strategic tools and a demonstration of their technological capacity. With the maturing of technologies, other researchers and institutes also began to develop their own projects. Today, satellites play an essential role for modern societies. Private companies have developed to the point where, today, they can commercialize services of launching satellites, probes and people, and even fully assembled satellites, as their customers wish, and which have already been delivered in orbit. The opportunity that was exclusive to big research institutes, private or governmental, is now part of the reality of many students, teachers and researchers around the world, with the creation of CubeSats projects. The short 2 International Conference on Environmental Systems development time, reduced size and the use of off-the-shelf components have made these projects an important tool in students’ development worldwide. Many research institutes are also using this strategy to develop experimental payloads and as a trusted platform for acquiring the information needed to develop their research projects. This concept began in 1999 when professors Bob Twiggs, at Stanford University, and Jordi Puig-Suari, at California Polytechnic State University developed the CubeSat concept with the intention of making it possible to use its idea for the development of university students1. Later the CubeSats were standardized in one “unit” (1U) a cube with 10 cm x 10cm x 10 cm and mass close to one kilogram. It can also be set with two units (2U) and three units (3U). With this standardization, it was possible to develop specific deployers that can be used in conventional launchers or in the ISS - International Space Station. CubeSats, as well as any component or equipment for space application, need to undergo thermal tests in order to ensure its operation and performance while fulfilling its mission. Among all the necessary tests are the thermal tests. This type of test is necessary because they can simulate the temperature variations and vacuum pressures imposed by the space environment, and reduce the outgassing rate of the materials and components to acceptable levels, since they are not 100% qualified for this application. In Brazil, these tests are carried out in the Integration and Testing Laboratory - LIT. This paper intends to show and discuss the lessons learned in the thermal tests, in levels of qualification and acceptance, of five projects tested at LIT. To do so, we will bring the information about the laboratory experience and its test facilities used in the tests, a CubeSats’ projects overview and all the lessons learned for performing the tests and, finally, our conclusions. II. History The thermal tests are fundamental to validate and qualify the Cubesat performance when it is exposed to temperature variations and vacuum pressures imposed by the space environment and also to reduce the degassing rates of the components to acceptable levels, due to the fact that these satellites have been frequently manufactured with components not 100% qualified for these purposes. In Brazil, the thermal tests are performed in the LIT – Integration and Tests Laboratory. A. Integration and Test Laboratory - LIT The LIT (Figure 1) is one of the laboratories of INPE – National Institute for Space Research, inaugurated in December 1987. It is specialized in all assemblies, integration, and test cycles for space components and systems2. In all its history, the LIT has supplied many of the needs of the spatial programs. Since the beginning of the Brazilian Space Program, the LIT has performed many thermal tests in satellites such as Data Collector Satellite - SCD-1[3], 2 e 2A, China- Brazil Earth Resources Satellite - CBERS-1, 24,5 and 2B, Humidity Sounder for Brazil – HSB6 (meteorological payload developed to equip Aqua Satellite - NASA), Technological Satellite – SATEC7, the thermal model test8 and all the Brazilian equipment and subsystems of CBERS 3-4, and the space simulation test of Scientific Application Satellites-D - SAC-D/Aquarius flight model9 (NASA / CONAE). Figure 1. LIT’s testing hall. B. CubeSat’s Thermal Test Facilities For the thermal test achievements two TVC – Thermal Vacuum Chamber and one TCC – Thermal Climatic Chamber of Thermal Vacuum and Climatic Test Group were used, at LIT, Brazil. The TCC is 1,000mm x 1,000mm x 1,000mm and is able to perform in a -100°C to 180°C temperature range, having humidity and temperature 3 International Conference on Environmental Systems gradient programmable.