Upvote:7
In 1492, Columbus sailed the ocean blue...
When Columbus approached King Ferdinand and Queen Isabella, the monarchs created a commission to study the feasibility of his idea. The group, called the Talavera Commission, concluded that Asia was too far away to be reached. The Commission was right and Columbus was wrong.
Ferdinand and Isabella sponsored the voyage anyway. Fortunately for the government of Spain--and tragically for everybody already living in the New World--Columbus ended up reaching the Americas.
This article has a lot more detail about the decision to sponsor the voyage.
To be clear, the arrival of Columbus was horrific for the countless people who had already lived in the area for generations. Your question seems to refer to success as defined by the government agency responsible for the intervention.