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The Advanced Land Observing Satellite (ALOS) that was launched by the Japan Aerospace Exploration Agency in 2006 carries a large solar array paddle of 22m x 3m in polar orbit. The wake side of the solar paddle can be charged to a negative value exceeding -1000V. Numerical simulations and laboratory experiments are carried out to investigate charging and arcing phenomena on the backside of the solar paddle that has exposed bypass diode boards and Silver-Teflon® thermal film. Possibility of secondary arc and surge voltage between hot and return ends of power circuit has been investigated. We irradiate solar panel coupons with an electron beam to simulate charging situation near the North Pole. Surface flashover is observed once the insulator potential exceeds -7000V.We have also tested charging situation near the South Pole, where Carbon Fiber-Reinforced Plastics (CFRP) surface facing dense ionospheric plasma may arc easily once a satellite potential drops to -80 or -90V. The solar paddle design has been modified to increase the safety margin against arcing and tests have been carried out to identify the strength limit under extremely harsh test environment. I.

This paper introduces the developed UAV system for low cost operation and an EOS (Electro Optical System) laboratory. This paper highlights an autonomous navigation system based on microcontrollers that can track a target using images, take three-dimensional measurements of the target, and acquire high quality images. The hardware system and an algorithm for the EOS verify the performance of the image tracking system and 3-D measurement of the target's position. 3-D position estimations for the target are solved using the mathematical relationship between the UAV and target. Although an on-board EOS can make errors in 3-D measurement, the proposed approach shows improved accuracy and confidence for 3-D target tracking using a postprocessing method.