From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Namekian Spaceship could only be piloted using commands in the Namekian language, which Mister Popo taught to Bulma Brief. Popo was also the one who showed the heroes the spaceship's location in the Yunzabit Heights where the Nameless Namekian had originally landed on Earth.
Later, it was used by Bulma, Kuririn, and Son Gohan to fly from Planet Earth to Planet Namek. The craft and its passengers made a stop on Fake Planet Namek before they arrived on the correct planet, where it was almost immediately destroyed by Freeza's Force.