Research on Stray-Light Suppression Method for Large Off-Axis Three-Mirror Anastigmatic Space Camera.

Area of Science:

• Optical Engineering
• Space Systems Engineering
• Image Science

Background:

• Stray-light suppression is critical for large off-axis three-mirror anastigmatic space cameras.
• Existing stray-light analysis models have limitations for large, rough surfaces.

Purpose of the Study:

• To develop and validate a composite stray-light suppression strategy for space cameras.
• To propose an adaptable stray-light analysis model for large mirrors.

Main Methods:

• Implemented a composite strategy using baffles, retaining rings, and internal measures.
• Designed a three-layered light barrier for the third mirror.
• Developed a wide-adaptability stray-light analysis model.
• Conducted simulations and experimental tests in a vacuum environment.

Main Results:

• Achieved point source transmittance of 10⁻⁵ before the light barrier, reducing to 10⁻⁸ after.
• Reduced veiling glare index from <5.8% to <1.31% across the field of view.
• Demonstrated minimal impact (<3.6%) on modulation transfer function.
• Verified clear imaging with SNR reaching 80 dB in out-of-field tests.

Conclusions:

• The proposed composite stray-light suppression strategy is highly effective for large off-axis space cameras.
• The new analysis model enhances stray-light simulation accuracy for large, rough mirrors.
• Experimental validation confirms the system's performance and minimal impact on optical quality.