USSR 1962 Vostok 3 & 4

Vostok 3 was launched on August 11, 1962, carrying cosmonaut Andrian Nikolayev for a nearly four-day spaceflight. The mission aimed to assess how the human body functions in weightlessness and to evaluate the endurance of the Vostok 3KA spacecraft during extended flights. Nikolayev completed 64 orbits of Earth over the course of August 11–15, 1962—a milestone that NASA would not achieve until the Gemini program in 1965-1966. On August 12, Pavel Popovich was launched on Vostok 4, completing 48 Earth orbits. The two capsules followed trajectories that brought them within approximately 6.5 km (4.0 mi) of each other, and they communicated via radio, marking the first ship-to-ship communications in space. These missions were significant as they represented the first instance of multiple crewed spacecraft in orbit simultaneously, allowing Soviet mission controllers to learn how to manage such scenarios.

A Vostok 3 cover featuring a special Baku postmark dated August 11, 1962.

A Vostok 3 cover featuring a special Kiev postmark dated August 11, 1962.

Vostok 4 was launched on August 12, 1962, just a day after Vostok 3, carrying cosmonaut Pavel Popovich. This marked the first time that two manned spacecraft were in orbit simultaneously. Although both spacecraft were in similar orbits (within 3-4 kilometers in altitude), they lacked the capability for rendezvous. At one point, they came within visual range of each other, and Popovich later noted in a news conference that he could see Vostok 3 from orbit, describing it as "a very small moon in the distance." The Vostok 4 mission proceeded mostly as planned, despite a malfunction in the life-support systems that caused the cabin temperature to drop to 10 °C (50 °F). The flight was cut short due to a misunderstanding with ground control, who thought Popovich had requested an early return. The two spacecraft landed approximately seven minutes apart and about 200 km from each other, south of Karaganda, Kazakhstan.

A Vostok 4 launch cover featuring a special Nikolaiev postmark dated August 12, 1962.

A Vostok 4 launch cover featuring a special Simferopol postmark dated August 12, 1962.

A Vostok 4 cover featuring a special Kiev postmark dated August 15, 1962.

A cover featuring a special Vinnitsa postmark for Vostok 3 and 4, dated August 15, 1962.

A commemorative stamp for Vostok 3 and 4, featuring a special Lvov postmark dated August 15, 1962.

Vostok 3 and 4 imperforate stamps on a First Day Cover, postmarked August 15, 1962, in Moscow, signed by Andrian Nikolayev and Pavel Popovich.