Development of a New Borosilicate Cover Glass and a Second Surface Mirror for Spacecrafts

Abstract

A cover glass and second surface mirror made of a new borosilicate glass (BDX) for scientific satellite are developed. The BDX consists of SiO₂, Al₂O₃, BaO and Na₂O. This glass has many features of efficient UV absorption, high transmittance and low alkali migration.
Two types of cover glasses (AR and CC) based on BDX are present. The type AR is coated with antireflection layer on the front surface. The type CC is coated with conductive layer/antirefiection layer on the front surface. The second surface mirror (type CSSM), front surface in coated by conductive layer/antirefiection layer and back surface is coated by Ag/protection layer.
This paper in describing the properties of BDX, two types of cover glasses and second surface mirror including results of evaluation by proton, electron, UV irradiation on the ground test and in space environment test with scientific satellite AKEBONO.