Which robotic system performed the first fully autonomous docking of two spacecraft in orbit in 1967?

Kosmos 186 and Kosmos 188 performed the first fully autonomous docking of two spacecraft in orbit in 1967.

The Soviet Union launched Kosmos 186 on October 27, 1967, and Kosmos 188 on October 30. Their spacecraft used an automated rendezvous and docking system, allowing the two vehicles to meet and connect without astronauts manually controlling the docking operation. They separated after several hours.

The achievement was a major step toward crewed space-station operations and later Soviet and Russian orbital missions. Soyuz 4 and Soyuz 5 achieved the first crewed docking in 1969, but that is a different milestone. Gemini 6A and Gemini 7 completed an important crewed rendezvous in 1965, yet they did not dock. The Kosmos mission therefore matters specifically for its autonomous, uncrewed orbital docking.