Transorbital balloon
From Halopedia, the Halo wiki
Transorbital balloons were a method used by the Forerunners to transport supplies to a planet from orbit. They were dropped from orbiting starships and inflated upon entering the atmosphere, decelerating and then landing gently.
These devices were used by the Forerunner government to provide supplies to the inhabitants of Seaward, a secret private resort planet.
