On October 15th, 1939, the Cuban Philatelic Club launch a rocket with around 200 letters that flied 6 m and then fell off. As an experiment did not succeed but the first stamp related to the cosmos was launched.
Suplemento de VNU Travel Network

On October 15th, 1939, the Cuban Philatelic Club launch a rocket with around 200 letters that flied 6 m and then fell off. As an experiment did not succeed but the first stamp related to the cosmos was launched.