A Lightship was an interstellar space vessel used by the people of Bajor. These ships were used from the 16th Century to the 21st Century and used Solar Sail technology to power the ship. The Bajorans used a lightship to make their fist contact with the Cardassians of Cardassia. However, Cardassians disclaim this to be a fact, refusing to believe that the Bajorans developed space travel before them.