FDC made in the Soviet Union. The text on the envelope reads:”12th. April, Cosmonautics Day”.
Cosmonautics Day is an anniversary celebrated in Russia and some other former USSR countries on 12 April. In 2011, 12 April was declared as the International Day of Human Space Flight in dedication of the first manned space flight made on 12 April 1961 by the 27-year-old Russian Soviet cosmonaut Yuri Gagarin. The commemorative day was established in the Soviet Union one year later, on 9 April 1962.
Nowadays the commemoration ceremony on Cosmonautics Day starts in the city of Korolyov, near Gagarin’s statue. Participants then proceed under police escort to Red Square for a visit to Gagarin’s grave in the Kremlin Wall Necropolis, and continue to Cosmonauts Alley, near the Monument to the Conquerors of Space.
On 7 April 2011, the United Nations General Assembly adopted a resolution declaring 12 April as the International Day of Human Space Flight. On 12 April 2017, the United Nations commemorated the “International Day of Human Space Flight” to celebrate the 56th anniversary of the first human space flight, which started the beginning of the space era for mankind.