A nickel-carbon-fibre composite for large adaptive mirrors: fabrication methods and properties

Abstract

We present results from our recent research into carbon-fibre composite (CFC) mirror fabrication for optical and infra-red applications. In particular this research is aimed towards the next generation of extremely large telescopes to offer an alternative to thin glass shell adaptive secondary mirrors. We address the issues involved with CFC mirror production, in particular the accuracy of the form replication process, a suitable surface for polishing to optical quality, no fibre print-through, environmental stability (shape change due to thermal and moisture variations), material uniformity and lifetime. We have performed experiments into the effectiveness of cold electroplating thick nickel coatings to totally encapsulate the CFC base substrate; the manufacturing procedure and properties of the Ni-CFC mirror are described here.

Large aperture telescope technology: a design for an active lightweight multi-segmented fold-out space mirror

“…UCL has been conducting research into CFRP mirrors for over 5 years, most recently into solid thin sheets of CFRP material coated in nickel which can be polished to optical (visible wavelengths) quality without fibre print-through [3,4]. An example of a Ni-CFRP mirror is shown in Fig.…”

Future high-resolution x-ray telescope technologies: prototype fabrication methods and finite element analysis

“…The electrolytic solution is nickel sulphamate and the temperature and pH are regulated to help minimise any stress in the final deposition. 10 The bath is run at a low current density compared to industrial applications, to ensure a low stress deposit. Rigorous cleaning of potential test pieces is implemented to ensure the electroforming quality as well as to guarantee that no foreign substances contaminate the bath.…”

Design, simulation and manufacturing a CFRP prototype mirror for active/adaptive optics

“…Composite materials offer low mass and tailorable properties and are perfectly suited to a wide variety of applications. In studies by Doel et al at UCL, composite mirrors have been created using a CFRP substrate that is fully coated in Nickel at a thickness of 50μm [1]. The purpose of the mirror demonstrator was to create an active deformable mirror to be used in a large ground-based telescope.…”