Soyuz 16 (Russian: Союз 16, Union 16) was a 1974 manned test flight for a joint Soviet-US space flight which culminated in the Apollo-Soyuz mission in July, 1975. The two-man Soviet crew tested a docking ring and other systems to be used in the joint flight.
Read more about Soyuz 16: Crew, Mission Parameters, Background, Mission Highlights