Gherman Stepanovich Titov (Russian: Герман Степанович Титов; 11 September 1935 – 20 September 2000) was a Soviet cosmonaut who, on 6 August 1961, became the second human to orbit the Earth, aboard Vostok 2, preceded by Yuri Gagarin on Vostok 1. He was the fourth person in space, counting suborbital voyages of US astronauts Alan Shepard and Gus Grissom.

Vladimir Georgiyevich Titov (Russian: Владимир Георгиевич Титов; born 1 January 1947 in Sretensk, Zabaykalsky Krai, Russia) is a retired Russian Air Force Colonel and former cosmonaut. He has participated in four spaceflight missions. The catastrophic explosion of a Soyuz rocket in 1983 led to him being one of only two people to use a launch escape system.

Michel Ange-Charles Tognini (born September 30, 1949 in Vincennes, France) is a French test pilot, Brigadier General in the French Air Force, and a former CNES and ESA astronaut. A veteran of two space flights, Tognini has logged a total of 19 days in space.

Valeri Ivanovich Tokarev (Russian: Валерий Иванович Токарев; born October 29, 1952) is a Russian Air Force Colonel and test cosmonaut at the Yuri A. Gagarin Cosmonaut Training Center. Tokarev traveled to space twice, and has performed two career spacewalks, before retiring in June 2008.

Sergei Yevgenyevich Treshchov (Сергей Евгеньевич Трещёв, born 18 August 1958) is a former cosmonaut of the RSC Energia. He spent 184 days in space as a flight engineer of the International Space Station long duration Expedition 5 crew. During the mission Treshchov also conducted a spacewalk. In 1992, he enrolled in the RSC Energia cosmonaut detachment, and from 1992 to 1994 he completed the basic Cosmonaut training course. Treshchov spent the next 3 years (1994 to 1996) in advanced Test Cosmonaut training. From June 1997 to February 1998, Treshchov trained as a flight engineer for the Mir station backup Exp-25 crew. From June 1999 to July 2000 he trained as a flight engineer for the Soyuz-TM backup ISS contingency crew. Initially, he trained as backup to the ISS Expedition 3 crew.

Bjarni Valdimar Tryggvason (born September 21, 1945) is an Icelandic-born Canadian engineer and a former NRC/CSA astronaut. He served as a Payload Specialist on Space Shuttle mission STS-85 in 1997, a 12-day mission to study changes in the Earth's atmosphere.

Vasily Vasiliyevich Tsibliyev (Russian: Василий Василиевич Циблиев); born on February 20, 1954) is a Russian cosmonaut. He was selected as a cosmonaut on March 26, 1987. Tsibliyev flew as Commander on Soyuz TM-17 from July 1, 1993 to January 14, 1994 and on Soyuz TM-25 from February 2, 1997 to August 14 of the same year. He retired on June 19, 1998. Tsibliyev is currently Chief of the Yuri Gagarin Cosmonauts Training Center at Star City, Russia. Tsibliyev was the commander in charge of Mir when it was hit by a Progress spacecraft in 1997.

Mikhail Vladislavovich Tyurin (Russian: Михаил Владиславович Тюрин) (born March 2, 1960) is a former Russian cosmonaut who flew several missions to the International Space Station and completed four spacewalks during his career. He is called a hero of the Russian Federation for his work as a cosmonaut. In 1994 he was selected to begin cosmonaut training, and in 1998 he started training as a flight engineer for the Expedition 3 crew. He also served as a backup crew member for the first ISS mission.

Yury Vladimirovich Usachov (Russian: Юрий Владимирович Усачёв; born October 9, 1957 in Donetsk, Rostov Oblast, Russia) is a former cosmonaut who resides in Star City, Moscow. Usachov is a veteran of four spaceflights, including two long duration missions on board the Mir Space Station and another on board the International Space Station.

Vladimir Vladimirovich Vasyutin (Russian:Влaдимиp Bлaдимиpoвич Васютин, born March 8, 1952, Kharkiv, Kharkiv Oblast, Ukrainian SSR, died July 19, 2002) was a Soviet cosmonaut. He was selected as a cosmonaut on December 1, 1978 (TsPK-6). He retired on February 25, 1986. Vasyutin was assigned to the TKS program for a new generation of manned military spacecraft that would be docked to the existing Salyut space stations. He flew as the Commander on Soyuz T-14 to the Salyut 7 space station, for part of the long-duration mission Salyut 7 EO-4. He spent 64 days 21 hours 52 minutes in space. The TKS module was already docked to the Salyut and Vasyutin was due to lead an extended programme of military space experiments. However Vasyutin fell ill soon after arriving at the station and was unable to perform his duties. Although he was originally scheduled to have a six-month stay aboard Salyut 7, his illness forced the crew to make an emergency return to Earth after only two months. His illness is said to have been caused by a prostate infection, which had manifested itself as inflammation and a fever.

Franz Artur Viehböck (born August 24, 1960 in Vienna) is an Austrian electrical engineer, and was Austria's first cosmonaut. He was titulated „Austronaut“ by his country's media. He visited the Mir space station in 1991 aboard Soyuz TM-13, returning aboard Soyuz TM-12 after spending just over a week in space.

Aleksandr Stepanovich Viktorenko (Александр Степанович Викторенко) was a Soviet cosmonaut. He was born in Olginka, North-Kazakhstan Oblast, Kazakh SSR on March 29, 1947. He is married with two children. He was selected as a cosmonaut on March 23, 1978, and retired on May 30, 1997. During his active career he had been Commander of Soyuz TM-3, Soyuz TM-8, Soyuz TM-14 and Soyuz TM-20. He has spent a total of 489 days in space.