Conversation so far:
How is Thor Heyerdahl related to the expedition of Easter Island?
Thor Heyerdahl organized the Norwegian Archaeological Expedition to Easter Island.
Who went with Thor Heyerdahl to the expedition of Easter Island?
The expedition's scientific staff included Arne Skjølsvold, Carlyle Smith, Edwin Ferdon, Gonzalo Figueroa and William Mulloy.
When did Thor Heyerdahl's expedition go to Easter Island?
In 1955–1956, Thor Heyerdahl organized the Norwegian Archaeological Expedition to Easter Island.
Was Thor Heyerdahl's trip to Easter Island a success?
Highlights of the project include experiments in the carving, transport and erection of the notable moai, as well as excavations at such prominent sites as Orongo and Poike.

Question: Was this the only expedition to Easter Island?
Self-contained rewrite: Was the 1955-1956 voyage Thor Heyerdahl's only expedition to Easter Island?