The Mede starship was a spacecraft used by the Medes. They could make both themselves and their ship invisible with staffs.
In the year 2050, two Medes came to Earth in a starship. They were captured by Inspector Drake of the Department and imprisoned. Drake tried to use their technology to spy on the people of London. These attempts caused chenium to leak into the River Thames, polluting it. The Medes tried to speak with K9 and the gang by using their avatar forms to direct K9 to the source of the pollution in the sewers.
June Turner found the source of pollution, a London warehouse, and shut down the project. She and the gang went to Dauntless Prison and released the Medes, returning their technology and apologising for their capture. The Medes cleaned up the Thames and returned home. (TV: Alien Avatar)