Vostok 3, launched on August 11, 1962, carried cosmonaut
Andrian Nikolayev for a near fours days spaceflight in order to determine the ability of the human body to function in conditions of weightlessness and test the endurance of the Vostok 3KA spacecraft over longer flights. Vostok 4 was launched a day after Vostok 3 on August 12, 1962, with cosmonaut
Pavel Popovich on board - the first time that more than one manned spacecraft were in orbit at the same time.
Vostok 3 & 4 imperforate stamps on FDC, postmarked August 15, 1962, Moscow, signed by Andrian Nikolayev and Pavel Popovich.
Vostok 3 Kniga cover signed by Andrian Nikolayev, one of the 6 covers marketed by Kniga.
Vostok 4 Kniga cover signed by Pavel Popovich, one of the 6 covers marketed by Kniga.
Vostok 3 & 4 imperforate stamps on FDC, postmarked August 15, 1962, Moscow, signed by Andrian Nikolayev and Pavel Popovich.
Vostok 3 Kniga cover signed by Andrian Nikolayev, one of the 6 covers marketed by Kniga.
Vostok 4 Kniga cover signed by Pavel Popovich, one of the 6 covers marketed by Kniga.
