Sergey Avdeev
Russian cosmonaut and amateur radio operator who held the space endurance record.
Sergei Vasilyevich Avdeyev, a Russian engineer and former cosmonaut, was born on 1 January 1956 in Chapayevsk, Samara Oblast. He earned a degree as an engineer-physicist from the Moscow Engineering Physics Institute in 1979, then worked as an engineer at NPO Energiya until 1987. On 26 March 1987, he was selected as a cosmonaut through the Energia Engineer Group 9, completing basic training from December 1987 to July 1989. He retired from active cosmonaut duty on 14 February 2003.
Avdeyev once held the record for the most cumulative time in space: 747.59 days, spread across three missions aboard the Mir Space Station. During those flights, he orbited Earth 11,968 times, covering roughly 515,000,000 kilometers. In August 2005, fellow cosmonaut Sergei K. Krikalev surpassed that record, and it has since been broken by others; as of February 2024, Oleg Kononenko holds the current record.
For a long period, Avdeyev also held the record for time dilation experienced by a human. Traveling at about 27,360 km/h over his 747 days on Mir, he aged approximately 0.02 seconds (20 milliseconds) slower than someone who remained on Earth—a consequence of special relativity. This effect is greater than that experienced by any other person except Krikalev. A common misconception credits Apollo astronauts with this record; while they flew faster, their time in space lasted only days.
Avdeyev’s three spaceflights were: Soyuz TM-15 (27 July 1992 to 1 February 1993, 188 days, 21 hours, 41 minutes, 15 seconds); Soyuz TM-22 (3 September 1995 to 29 February 1996, 179 days, 1 hour, 41 minutes, 45 seconds); and Soyuz TM-28 and Soyuz TM-29 (13 August 1998 to 28 August 1999, 379 days, 14 hours, 51 minutes, 9 seconds). He performed ten spacewalks totaling 42 hours and 2 minutes, with durations ranging from 30 minutes to over six hours.
Avdeyev is married with two children and is an amateur radio operator with call sign RV3DW. His honors include Hero of the Russian Federation (5 February 1993), the Order of Merit for the Fatherland (2nd class, 22 November 1999; 3rd class, 1 April 1996), the Medal "For Merit in Space Exploration" (12 April 2011), Chevalier of the Legion of Honour (France, March 1999), the title Pilot-Cosmonaut of the Russian Federation (5 February 1993), and Honorary Citizen of Chapayevsk, Samara Oblast (2004).
Quick Facts
- Birth Date
- 1 January 1956
- Birth Place
- Chapayevsk, Russian SFSR, Soviet Union
- Occupation
- Engineer
- Selection
- 1987
- Evas
- 10 (4 during Mir EO-12, 2 during Mir EO-20, 2 during Mir EO-26, 2 during Mir EO-27)
- Time
- 747d 14h 14m
- Mission
- Soyuz TM-15 (Mir EO-12), Soyuz TM-22 (Mir EO-20), Soyuz TM-28/Soyuz TM-29 (Mir EO-26/27)
- Eva Time
- 42h, 07m
- Awards
- Hero of the Russian Federation
Facts from the source article.
Lore & Background
Avdeyev graduated from Moscow Engineering Physics Institute in 1979 as an engineer-physicist and worked for NPO Energiya from 1979 to 1987. He was selected as a cosmonaut on 26 March 1987 as part of the Energia Engineer Group 9, completed basic training from December 1987 through July 1989, and retired on 14 February 2003. His three spaceflights were Soyuz TM-15 (1992–1993), Soyuz TM-22 (1995–1996), and Soyuz TM-28/TM-29 (1998–1999), totaling 747.59 days. He performed ten spacewalks totaling 42 hours and 2 minutes. Avdeyev held the record for cumulative time in space until August 2005, when it was taken by Sergei K. Krikalev; the current record holder since February 2024 is Oleg Kononenko.
Reader's Guide
Avdeyev's significance lies in his record for cumulative time in space and the associated time dilation effect. During his 747 days aboard Mir, traveling at approximately 27,360 km/h, he aged roughly 0.02 seconds (20 milliseconds) slower than an Earthbound person due to special relativistic time dilation. This was the greatest time dilation experienced by any human being for a long time, except for Sergei Krikalev. A common misconception is that Apollo astronauts hold this record; they traveled faster but only for a few days. Avdeyev's record for cumulative time in space was later surpassed, but his contribution to understanding long-duration spaceflight and relativistic effects remains notable. He was awarded Hero of the Russian Federation, the Order of Merit for the Fatherland (2nd and 3rd class), the Medal 'For Merit in Space Exploration', and the Chevalier of the Legion of Honour (France).
Did You Know?
- Avdeyev orbited Earth 11,968 times, traveling about 515,000,000 kilometers.
- He held the record for time dilation experienced by a human being, aging 20 milliseconds slower than an Earthbound person.
- His amateur radio call sign is RV3DW.
- He was awarded the Hero of the Russian Federation on February 5, 1993.
More in Amateur Radio People, Part 3 1-24
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