Chinese Optics, Volume. 18, Issue 1, 150(2025)
Design of the central support structure of a large aperture mirror with a wide working temperature
Fig. 4. Influence of adhesive layer height on primary mirror surface accuracy
Fig. 5. Relationship between adhesive thickness and working performance of primary mirror
Fig. 6. Schematic diagram of variable-orientation gravity conditions
Fig. 10. Primary mirror’s application in commercial ground station
Table 1. Main design metrics for primary mirror components in commercial ground station
View tableView in ArticleTable 1. Main design metrics for primary mirror components in commercial ground station
No. Item Requirement 1 Clear aperture Φ500 mm 2 Elevation during pointing From horizontal to vertical 3 Deformation under gravity Tilt: θX≤10″, θY≤10″ Displacement: δX≤20 μm, δY≤20 μm 4 Working temperature range −20 °C~40 °C 5 Surface accuracy RMS≤1/30λ (λ=632.8 nm) 6 Mass ≤30 kg 7 Frequency ≥30 Hz
Table 2. Physical properties of primary mirror assembly components
View tableView in ArticleTable 2. Physical properties of primary mirror assembly components
Property Mirror Adhesive Bushing Support Material & type Zerodur RTV TC4 TC4 Density ρ (g·cm−3) 2.53 1.1 4.4 4.4 Elastic modulus E (MPa) 91000 2.7 109000 109000 Poisson ratio μ 0.24 0.47 0.34 0.34 Thermal expansion coefficient α (10−6·K−1) 0.1 185 9.1 9.1
Table 3. Primary mirror’s simulation results under main load cases (λ=632.8 nm)
View tableView in ArticleTable 3. Primary mirror’s simulation results under main load cases (λ=632.8 nm)
Load case Deformation/nm Displacement/ μm Tilt/″ RMS δX δY δZ θX θY Temperature variation（40ºC） 4.199 0 0 58.325 0.008 0.008 Horizontal gravity 4.187 3.597 0 0.001 0.235 4.722 Vertical gravity 13.748 0 0 13.415 0.004 0.004 Compound gravity（45°） 10.161 2.542 0 9.572 0.167 3.339 Design Criterion ≤1/30λ ≤20 ≤20 / ≤10 ≤10
Table 4. Modal analysis results of primary mirror assembly
View tableView in ArticleTable 4. Modal analysis results of primary mirror assembly
Order Frequency/Hz Vibration mode 1st 53.45 Rotation of mirror around Z axis 2nd 66.09 Rotation of mirror around X axis 3rd 66.10 Rotation of mirror around Y axis
Table 5. Primary mirror’s surface accuracy test results
View tableView in ArticleTable 5. Primary mirror’s surface accuracy test results
Surface accuracy Polishing Heat recycle Coating RMS / λ (λ=632.8nm) 0.017 0.018 0.018
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Jian YUAN, Si-yu PEI, Zhan-wei HUO, Guan-chen ZHANG, Lei ZHANG. Design of the central support structure of a large aperture mirror with a wide working temperature[J]. Chinese Optics, 2025, 18(1): 150
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Received: Mar. 25, 2024
Accepted: Jul. 12, 2024
Published Online: Mar. 14, 2025
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