Sunshield

Sunshield is a shading device designed to block sunlight and reduce heat and glare in a system or space. It serves to maintain temperature stability, protect sensitive optics or electronics, and improve energy efficiency or comfort.

In space technology, sunshields are large, multi-layer structures placed between an instrument and the Sun to keep temperatures low and stable, shielding lenses, detectors, and cryogenic components from solar radiation and stray heat. They are usually made of reflective films with multiple layers and are deployed after launch. The James Webb Space Telescope uses a five-layer sunshield that blocks and radiates heat away, enabling its infrared observations.

In architecture, sunshields refer to exterior shading devices such as overhangs, fins, louvers, and shading screens that reduce solar gain while preserving daylight. They are designed to balance heat intake with visible light, often adjustable to respond to sun angle and climate, and are a common feature in hot climates to lower cooling loads.

Other applications include consumer products like camera and display shading hoods, and vehicle sun visors, though these uses are more typically referred to as shading devices or visors.

Design considerations include thermal performance, weight, deployment reliability for space-based systems, weather resistance, aesthetics, and maintenance.