SUPERBLACK COATINGS FOR SPACE COMPONENTS

Optical observation from space is highly demanding in terms of the control accuracy of the optical payload parameters, among which, stray light is a major contributor. The last, might affect the geometric and radiometric image quality.

Minimizing the stray light level is therefore of high relevance, and it is usually addressed using baffles that surround the optical system to prevent the detection of radiation originating from off axis bright objects. To enhance the attenuation factor of the baffle, the inner walls are designed with concentric vanes providing a complex three dimensional structure. The implementation of superblack coating on the inner surfaces of the baffle/vanes assembly releases the demand in terms of geometrical complexity, and is expected to significantly reduce their cost, and weight, while improving the performance.

A black coating needs to comply with a number of criteria before its implementation for space applications. These criteria guaranties that the coating withstands the aggressive space environment.

The performed study has enabled the space qualification of the superblack coating composed of CNT and an Al-doped silicon oxide reinforcement layer. The environmental tests involved hygroscopic ageing, thermal cycling and exposure to UV, ATOX and ionizing radiations. The monitored parameters were the optical properties referring to the space requirements and the adhesion. Although the effect of ageing could be measured, the space requirements are still met. The CNT-based composite coating is therefore qualified for space application and demonstrations were performed on functional components including a field stop, blackbody reference, barrels, rings and baffles.

4000119752 closed in August.