Cells wholeness inspection for solar array used on perspective spacecrafts

New types of primary power supply have been used for wide application in Electric Power Systems (EPS) of space- crafts (S/C) recently. These are Solar arrays (SA) based on three-stage GaAs cells instead of Si cells. GaAs cells specific data is their low thickness and fragility. Due to that they have low resistance to mechanical stress and crack. Cracks in cells cause their power decrease and SA power decrease in whole. At the present time SA maintenance is carried out by the following methods: the visual method of cells wholeness in- spection (to detect cells and protective glass wholeness), SA current-voltage characteristic measurement, and the elec- tro-luminescence method. These methods do not allow detecting defects reliably and safely like hidden cracks in cells. It is necessary to define the method which will help to detect a defective cell without direct SA connection. It means a non-contact method. The content of the proposed method consists in cells illumination by lasing with wave length (0.40-0.55) µm (the green spectrum domain). It produces luminescence and the cell reflects light in the red spectrum domain. The experiment of automatic visual SA cells inspection has been performed on the test stand at JSC “ISS”. This stand has the moving platform which can be moved along SA as in vertical and also horizontal directions. On the plat- form there is a camera and laser producing light in the green spectrum domain. When the platform is set opposite the tested cell, laser is switched on and its beam is pointed at the cell. Lumines- cence appears in lasing and the cell surface reflects the light in the red spectrum domain. The camera registers the emission to measure the cell luminescence spectrum intensity by means of software (S/W). Then this value is compared by S/W with luminescence spectrum intensity value received and recorded in PC mem- ory before the cell- etalon testing. This test stand based on the electro-luminescence method allows us to define cells defects presence without contact and hidden cracks; to decrease impact of human factor.