Electrostatic Discharge Ground Test of a Polar Orbit Satellite Solar Panel

The Advanced Land Observing Satellite that was launched by the Japan Aerospace Exploration Agency in 2006 carries a large solar-array paddle of 22 times 3 m in polar orbit. The wake side of the solar paddle can be charged to a negative value exceeding -1000 V. 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. The authors 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 -7000 V. The authors have also tested charging situation near the South Pole where carbon fiber-reinforced plastics surface facing dense ionospheric plasma may arc easily once a satellite potential drops to -80 or -90 V. 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

Number of Arcs Estimated on Solar Array of a Geostationary Satellite

Plasma parameters of geosynchronous orbit measured by Los Alamos National Laboratory satellites are analyzed statistically. For each set of plasma parameters, charging analysis is carried out, taking a geostationary satellite representing a typical telecommunication satellite as an example. The number of expected trigger arcs on a solar array is calculated based on the charging duration with severe inverted potential gradient conditions expected in orbit. Using the number of trigger arcs, an appropriate duration of electrostatic discharge ground test is proposed to test the insulation strength against sustained arc phenomena

On-Orbit Operations of A Power System For Japan’s Venus Explorer Akatsuki

This paper describes on-orbit operations of a power system for Japan’s Venus explorer Akatsuki. It was launched on May 20, 2010, and approached Venus on December 7, 2010, but orbit insertion failed because of a propulsion system malfunction. After the failure, the spacecraft stayed on an orbit nearer to the sun than Venus for 5 years before successfully entering an orbit around Venus in 2015. Telemetry data that show radiation degradation of the solar arrays, and here analytical results by the relative damage coefficients method are presented. The capacity loss of the batteries was successfully suppressed by lowering the state of charge and temperature. We plan to extend the mission period from 4.5 years to longer than 9 years to obtain more fruitful scientific results

Qualification Test Results of IMM Triple-Junction Solar Cells, Space Solar Sheets, and Lightweight&Compact Solar Paddle

Development of a high specific power, low stowage volume and lightweight solar paddle utilizing high-efficiency, thin-film, InGaP/GaAs/InGaAs inverted metamorphic triple-junction solar cell has been completed. The cell exhibits the efficiency of as high as 32% with sufficient radiation resistance. Owing to the high efficiency of the cell, the paddle achieved the specific power of greater than 150 W/kg. Qualification and reliability tests for the cell and paddle were carried out. The results confirmed that both the cell and paddle have enough capability to use them in space. Space demonstration of the paddle is now in preparation

Qualification Test Results of IMM Triple-Junction Solar Cells, Space Solar Sheets, and Lightweight&Compact Solar Paddle

Development of a high specific power, low stowage volume and lightweight solar paddle utilizing high-efficiency, thin-film, InGaP/GaAs/InGaAs inverted metamorphic triple-junction solar cell has been completed. The cell exhibits the efficiency of as high as 32% with sufficient radiation resistance. Owing to the high efficiency of the cell, the paddle achieved the specific power of greater than 150 W/kg. Qualification and reliability tests for the cell and paddle were carried out. The results confirmed that both the cell and paddle have enough capability to use them in space. Space demonstration of the paddle is now in preparation

ESD Ground Testing of Triple-Junction Space Solar Cells with Monolithic Diodes

High-efficiency triple-junction (TJ) solar cells with monolithic diodes (MD) are being used for recent spacecraft solar arrays. Because the cell-to-cell inter-connector is usually connected on the MD pad, studying the effects of electrostatic discharge (ESD) on MD is necessary. Laboratory testing of two types of MD functions revealed that the weaker design was damaged by an energy discharge of 0.8J. With an external circuit simulating flight solar array, however, discharge as large as 9.3J didn\u27t destroy the solar cell. Based on the test results, it was concluded that MD solar cells have sufficient resistance against ESD in orbit.26th International Symposium on Space Technology and Science, June 2-6, 2008, Hamamatsu, Japa

ESD Ground Testing of Triple-Junction Space Solar Cells with Monolithic Diodes

High-efficiency triple-junction (TJ) solar cells with monolithic diodes (MD) are being used for recent spacecraft solar arrays. Because the cell-to-cell inter-connector is usually connected on the MD pad, studying the effects of electrostatic discharge (ESD) on MD is necessary. Laboratory testing of two types of MD functions revealed that the weaker design was damaged by an energy discharge of 0.8J. With an external circuit simulating flight solar array, however, discharge as large as 9.3J didn't destroy the solar cell. Based on the test results, it was concluded that MD solar cells have sufficient resistance against ESD in orbit