Tephra was a substance ejected by volcanoes on the planet Lah'mu. Minerals in tephra made groundwater on the planet unpleasant to drink, so the Erso family employed GX-8 water vaporators at their homestead to collect water vapor from the air.
Tephra was a substance ejected by volcanoes on the planet Lah'mu. Minerals in tephra made groundwater on the planet unpleasant to drink, so the Erso family employed GX-8 water vaporators at their homestead to collect water vapor from the air.