It is crucial that JWST be shielded from direct and reflected sunlight — light reflected from the Earth and its Moon — and maintain cryogenic, or very cold, temperatures to guarantee its operational success. The observatory’s sunshield performs this task.

The sunshield, approximately the size of a tennis court, has five layers of reflecting material and can sustain a 300° Kelvin (300° Celsius, or 540° Fahrenheit) temperature drop. Folded around and protecting the optical telescope element at launch, the sunshield will be commanded to unfold when JWST is on its way to its final L2 orbit.

In conjunction with the L2 orbit, the sunshield maintains a stable, cold environment with a minimum of background radiation. This ensures optimal conditions for JWST’s instruments to achieve the best results.