Technological facilities for the integration and testing of solar arrays for space applications

M. A. ALURRALDE; C.G. BOLZI; J. DI SANTO; J. GARCÍA; L. GONZALEZ; V. GOLDBECK; M. G. MARTÍNEZ BOGADO; S. MUÑOZ; J.M. OLIMA; J. PEREZ; D. RAGGIO; O. ROMANELLI; C. RINALDI; H. P. SOCOLOVSKY; M. J. L. TAMASI

Buenos Aires

Simposio; 1st IAA Latin American Symposium on Small Satellites: Advanced Technologies and Distributed Systems; 2017

This paper describes the technological facilities for the integration and testing of solar arrays for space applications at DES-CNEA labs. It should be remarked that NASA and ESA documents have been taken as references for these developments.Relevant issues such as, solar cells and diodes characterization, set up of soldering and bonding processes, radiation damage and development of testing techniques, are presented. The DES activities on flight components carried out in two clean rooms - Class 10,000 and Class 100,000 and a specialist electronics lab. Other development work are carried out in different facilities belonging to the Tandar Accelerator Laboratory, CNEA.For electrical charaterization, DES has three measuring systems: i) multiflash technique, ii) a simple solar simulator Class C AM 1.5, adjusted to deliver a radiation intensity equivalent to 1 kW/m2; and iii) a TS-Space ?Close-match? high fidelity steady-state solar simulator with AM0 spectrum and normalized equivalent irradiance to 1367 W/m2 and electronic data acquisition system development by DES.For welding processes, the system used consisted of a programmable DC power supply and a parallel-gap welding head made by Unitek Co. It allows programming the welding cycles, number of pulses, pulse amplitude, pulse time, modes of current flow, weld force, magnitude/time, etc. Back side soldering is a reliable, established process. The joints have made with a programmable reflow Unitek system with controlled temperature profile and solder preforms consisting of a Sn/Pb/Ag alloy. The principal parameters of the system were thermode type and force, temperature and time.In space applications solar cells are protected by coverglasses from UV exposure and from low energy charged particles. An activities related to bonding techniques are development. These are bonding coverglasses to cells, bonding stringed cells to substrate, bonding buses to substrate, bonding cables and electronic devices to substrate.The radiation damage tests allow to study the degradation of electrical parameters on electronics devices (such as diodes, solar cells, sensors, etc.) under irradiation effects with protons or electrons. In CNEA, there are available facilities and equipment necessary to carry out irradiation with protons with energies ranging from a few keV to hundreds of MeV at Tandar 20 MV Tandem Van de Graaff Accelerator Laboratory.Visual inspection test are carried out between each of the above tests mentioned through electro-luminescence in order to detect small cracking at the cells.