Zion

Mass Effect
Zion is a hydrogen-helium gas giant even larger than Jupiter. Despite its deep gravity well and lethal radiation, it supports a small helium-3 mining industry. The reason is simple; as the only gas giant in the Utopia system, it is the only local source of fuel for Eden Prime's power stations and space ports.

Zion has 112 satellites, ranging from captured asteroids to the moon of Asphodel, which is large enough to retain a thick atmosphere.

Mass Effect 3
Zion is a hydrogen-helium gas giant even larger than Jupiter. Despite its deep gravity well and lethal radiation, it supports a small helium-3 mining industry. The reason is simple: as the only gas giant in the Utopia system, it is the only local source of fuel for Eden Prime's power stations and spaceports.

Zion has 112 natural satellites, ranging from orbiting asteroids to the moon as Asphodel, which is large enough to retain a thick atmosphere.