CFRP composite mirrors for space telescopes and their micro-dimensional stability

Abstract

Ultra-lightweight and high-accuracy CFRP (carbon fiber reinforced plastics) mirrors for space telescopes were fabricated to demonstrate their feasibility for light wavelength applications. The CTE (coefficient of thermal expansion) of the all-CFRP sandwich panels was tailored to be smaller than 1x10 -7 /K. The surface accuracy of mirrors of 150 mm in diameter was 1.8 um RMS as fabricated and the surface smoothness was improved to 20 nm RMS by using a replica technique. Moisture expansion was considered the largest in un-predictable surface preciseness errors. The moisture expansion affected not only homologous shape change but also out-of-plane distortion especially in unsymmetrical compositions. Dimensional stability due to the moisture expansion was compared with a structural mathematical model.

Development of CFRP mirrors for space telescopes

“…Shape deformation of CFRP mirrors due to moisture expansion was observed to be similar with thermal distortion [2]. It is noted that shape accuracy of CFRP mirrors must be estimated in dried condition …”

“…We have developed all CFRP mirrors of sandwich structures [2]. CFRP face skins and CFRP honeycomb cores were made of high modulus pitch carbon fibers and cyanate ester resin matrix.…”

Radiation and electrostatic resistance for ultra-stable polymer composites reinforced with carbon fibers

“…For many space missions, highly stable, lightweight, and functional structures are essential to support precision apertures and finely calibrated instruments on satellites (1)(2)(3)(4). Stable structures, such as optical benches, telescope tubes, parabolic reflectors, rovers, and lander structures, are required for precision optics, radar, and scientific instruments for various deep-space, Earth, Observation, Navigation and Science (ENS), and exploration missions (5)(6)(7)(8)(9)(10)(11). It is imperative that these structural components maintain the highest performance under extreme test, launch, and space conditions to ensure mission viability (12)(13)(14).…”

Research on sub‐micron measurement methods of M55J carbon fibre/cyanate ester composites

“…Dimensional stability against temperature changes in orbit environments and is primarily concerned in structure design. The CTE of composites can be tailored to suit particular applications by appropriate choice of graphite fibre, matrix resin, and fibre volume fraction and lay‐up orientation [14] Ma Li et al adopted the domestically produced HM2 high modulus carbon fibre‐reinforced epoxy resin matrix composites and manufactured a high‐precision truss structure for space use through layering design. The deformation test results show that high modulus carbon fibre composites can produce high‐stability structures with micron‐scale thermal deformation [15].…”