Modulated solar pressure-based surface shape control of paraboloid space reflectors with an off-axis Sun-line

Liu, J. and McInnes, C. (2018) Modulated solar pressure-based surface shape control of paraboloid space reflectors with an off-axis Sun-line. Smart Materials and Structures, 27(3), 035012. (doi: 10.1088/1361-665X/aaac3a)

Abstract

This paper considers utilizing solar radiation pressure (SRP) to actively control the surface shape of a reflector consisting of a rigid hoop and slack membrane with embedded reflectivity control devices (RCDs). The full nonlinear static partial differential governing equations for a reflector with negligible elastic deformations are established for the circumferential, radial and transverse directions respectively, in which the SRP force with ideal /non-perfect models, the centripetal force caused by the rotation of the reflector and the internal stresses are considered. The inverse problem is then formulated by assuming that the required surface shape is known, and then the governing algebraic-differential equations used to determine the required surface reflectivity together with the internal stresses are presented accordingly. The validity of the approach is verified by comparing the results in the paper with the corresponding published results as benchmarks. The feasible regions of the angular velocity and Sun angle for a paraboloidal reflector with an invariant radius and focal length (case 1), and the achievable focal lengths with a specific angular velocity and Sun angle (case 2) are presented for the two SRP models respectively, both by considering the restrictions on the reflectivity and internal stresses. It is then found that the feasible region is toward a larger angular velocity and Sun angle when using the non-perfect SRP model compared with the ideal one in case 1. The angular velocity of the spinning reflector should be within a certain range to make the required reflectivity profiles within a practical range, i.e., [0, 0.88], as indicated from prior NASA solar sail studies. In case 2, it is found that the smallest achievable focual length of the reflector with the non-perfect SRP model is smaller than that with the ideal SRP model. It is also found that the stress level is extremely low for all cases considered and the typical real material strength available for the reflector is sufficient to withstand these internal stresses.

• Item Type: Articles
• Additional Information: JL was support by NSFC (11302134) and China Scholarship Council program (201508210053). CM was support by a Royal Society Wolfson Research Merit Award.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Liu, Dr Jiafu and McInnes, Professor Colin
• Authors: Liu, J., and McInnes, C.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Smart Materials and Structures
• Publisher: IOP Publishing
• ISSN: 0964-1726
• ISSN (Online): 1361-665X
• Published Online: 01 February 2018
• Copyright Holders: Copyright © 2018 IOP Publishing Ltd.
• First Published: First published in Smart Materials and Structures 27(3):035012
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher