Thermal Effects On Beryllium Mirrors

Shep Weinswig

doi:10.1117/12.960951

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26 October 1989 Thermal Effects On Beryllium Mirrors

Shep Weinswig

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Proceedings Volume 1118, Space Optical Materials and Space Qualification of Optics; (1989) https://doi.org/10.1117/12.960951
Event: SPIE 1989 Technical Symposium on Aerospace Sensing, 1989, Orlando, FL, United States

Abstract

Beryllium is probably the most frequently used material for spaceborne system scan mirrors. Beryllium's properties include lightweightedness, high Young's modulus, high stiffness value, high resonance value. As an optical surface, beryllium is usually nickel plated in order to produce a higher quality surface. This process leads to the beryllium mirror acting like a bimetallic device. The mirror's deformation due to the bimetallic property can possibly degrade the performance of the associated optical system. As larger space borne systems are designed and as temperature considerations become more crucial in the instruments, the concern about temporal deformation of the scan mirrors becomes a prime consideration. Therefore, two sets of tests have been conducted in order to ascertain the thermal effects on nickel plated beryllium mirrors. These tests are categorized as follows: 1. On seven small samples of nickel plated beryllium, the bimetallic effect was measured under very controlled conditions. 2. On a large (20" diameter) nickel plated beryllium space quality mirror, the bending of the mirror as a function of temperature was determined. The purpose of this paper is to present the values of the bimetallic effect on typical nickel plated beryllium mirrors.

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Shep Weinswig "Thermal Effects On Beryllium Mirrors", Proc. SPIE 1118, Space Optical Materials and Space Qualification of Optics, (26 October 1989); https://doi.org/10.1117/12.960951

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