Microsat: Solar Array Exposed Materials Protection from Atomic Oxygen

Microsat is the third satellite in the series of remote sensing micro-satellites by ISRO. It is a low earth orbit (LEO) spacecraft, launched into a 350-km circular orbit on 12 January 2018. The orbit of 350 km poses lot of constraints on the satellite with respect to space environment as well as atmospheric drag. The major concern is from atomic oxygen present in the LEO environment. The interaction between atomic oxygen and spacecraft surfaces produces significant changes in the mass, surface morphology, electrical and optical properties of the spacecraft materials through erosion and oxidation. The major exposed materials of solar panels, viz. silver, Kapton and epoxy, are vulnerable to atomic oxygen effect. For LEO missions (<500 km), erosion rates of solar array materials can be high and can cause degradation in their mechanical, thermal and electrical properties. In recent years, many nanosatellites and student satellites are launched into low earth orbits for technology demonstration. Hence, understanding of the performance degradation of solar array exposed materials is very critical for the low-altitude satellites. To protect the exposed surfaces, mitigation technique needs to be adopted. In this chapter, the effect of atomic oxygen on the solar array exposed materials, details of the protection coatings, its qualification and on-board performance are presented.