Optimization of lightweight structure and supporting bipod flexure for a space mirror

Area of Science:

• Optomechanical Engineering
• Optical Design
• Mechanical Design

Background:

• Integrated optomechanical design requires balancing optical performance with structural integrity.
• Finite Element Analysis (FEA) is crucial for predicting mirror deformation under load.
• Accurate transfer of structural deformation data to optical performance metrics is essential.

Purpose of the Study:

• To develop and demonstrate an automated optimization process for integrated optomechanical design.
• To achieve optimal lightweighting of a primary mirror for a spaceborne telescope.
• To design an optimized bipod flexure support system for enhanced mirror stability.

Main Methods:

• Utilized computer-aided drafting, FEA for mirror deformation analysis, and MATLAB optomechanical transfer codes.
• Integrated FEA, optical transfer codes, and an optimization solver using a Tcl script for automated iterations.
• Applied Zernike polynomials to quantify optical path difference (OPD) and aberrations from deformed mirror data.

Main Results:

• Successfully optimized a 566 mm Zerodur primary mirror, increasing its lightweight ratio from 56% to 66%.
• Developed an optimized bipod flexure design that significantly reduced mirror's peak-to-valley (PV) OPD from 228 nm to 61 nm.
• Achieved minimum PV values for OPD in both example designs, demonstrating effective aberration reduction.

Conclusions:

• The automated optomechanical design optimization process is effective for spaceborne telescope applications.
• The developed method successfully enhances structural lightweighting while maintaining or improving optical performance.
• The integrated approach provides a robust framework for designing high-performance optomechanical systems.