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

Abstract

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.