From Halopedia, the Halo wiki
Planetary shields were a variant of Forerunner energy shielding technology that could be extended to cover entire planets to protect from stellar radiation. Sections of a planetary shield could be temporarily lowered to allow starships to pass through. Normally, a planetary shield was barely visible, but caused noticeable refraction when opening or during sunset. The homeworld of Bornstellar Makes Eternal Lasting was protected by a planetary shield.
List of appearances
- Halo: Cryptum (First appearance)