Expedition 68

Expedition 68 was the 68th long-duration expedition to the International Space Station. The expedition began upon the departure of Soyuz MS-21 on 29 September 2022, with ESA astronaut Samantha Cristoforetti taking over as ISS commander, and ended upon the uncrewed departure of the Soyuz MS-22 spacecraft on 28 March 2023.

Background, Crews and Events
Initially, the expedition consisted of Cristoforetti and her three SpaceX Crew-4 crewmates Kjell N. Lindgren, Bob Hines, and Jessica Watkins, as well as Roscosmos cosmonauts Sergey Prokopyev, Dmitry Petelin, and American astronaut Francisco Rubio, who launched aboard Soyuz MS-22 on September 21, 2022 and were transferred from Expedition 67 alongside the Crew-4 astronauts.

Crew-4 departed the station on 14 October 2022 and was replaced by SpaceX Crew-5 through a direct handover, which ferried NASA astronauts Nicole Mann and Josh Cassada, as well as JAXA astronaut Koichi Wakata and Roscosmos cosmonaut Anna Kikina to the station. Before departing, Cristoforetti handed command of the station over to Prokopyev.

On December 14, 2022, a coolant leak was discovered on the docked Soyuz MS-22 vehicle, causing it to leak ammonia, which forced the cancellation of an imminent Russian spacewalk.

After observation and imaging of the damaged spacecraft, in January 2023, Roscosmos and NASA announced that due to the leak, the MS-22 vehicle could not safely return the crew, except in an emergency. The governing bodies also announced changes to the crew manifest: the crew remaining on the station for 12 months and the Soyuz MS-22 spacecraft to return uncrewed. The Soyuz MS-23 spacecraft was launched uncrewed in February, and the crew returned to Earth on 27 September 2023. The original MS-23 crew instead launched on Soyuz MS-24 to work on the station for both Expedition 69 and 70 instead of Expedition 68 and 69. Rubio's seat liner was shifted to Crew 5 and ultimately all Soyuz MS-22 seat liners were shifted to Soyuz MS-23 as seat liner are specifically designed to seat the cosmonaut seat in it. Usually, this seat liner swapping is not new between two Soyuz but first time for Soyuz to Crew Dragon.

In February, on the day of docking for the Progress MS-22/83P vehicle, another Russian craft Progress MS-21/82P, experienced a coolant leak, the second to occur on station in just two months. Due to this, Russian officials on the ground had postponed the uncrewed launch of the Soyuz MS-23 until an investigation was conducted or a cause was found. Days after the leak, it was determined safe to launch Soyuz MS-23, being launched on February 24. Roscosmos conducted a thermal test of MS-22 which lost coolant agent in the external contour due to the damage of the radiator.

In an unrelated change to the US crew manifest, SpaceX's Crew-6 mission launched on 2 March 2023, as opposed to the usual launch date of April/September. Traditionally, expeditions end with the departure of a Soyuz. This continues with Expedition 68, albeit without crew onboard. All onboard crew were transferred to Expedition 69 with the departure of Soyuz MS-22 on 28 March.

Events manifest
Previous mission: Expedition 67

29 September 2022 - Soyuz MS-21 Undocking; Official switch from Expedition 67

6 October 2022 - SpaceX Crew-5 Docking

12 October 2022 - ISS Expedition 68 Change of Command Ceremony from Samantha Cristoforetti to Sergey Prokopyev

14 October 2022 - SpaceX Crew-4 Undocking

9 November 2022 - CRS Cygnus NG-18 Capture

9 November 2022 - CRS Cygnus NG-18 Berthing

23 October 2022 - Progress MS-19/80P Undocking

27 October 2022 - Progress MS-21/82P Docking

15 November 2022 - EVA 1 (US-81): 7 hrs, 11 mins

17 November 2022 - EVA 2 (VKD-55): 6 hrs, 25 mins; installed a work platform called the SKKO (translation: Nauka means of attachment of large payloads) on the Nauka module

27 November 2022 - CRS SpX-26 Docking

3 December 2022 - EVA 3 (US-82): 7 hrs, 5 mins; installed an iROSA at Array 3A

14 December 2022 - Soyuz MS-22 Leak, cancelled Russian EVA

22 December 2022 - EVA 4 (US-83): 7 hrs, 8 mins; installed the fourth iROSA at Array 4A

9 January 2023 - CRS SpX-26 Undocking

17/18 January 2023 - Rubio's seat liner moved from Soyuz MS-22 to Crew-5

20 January 2023 - EVA 5 (US-84): 7 hrs, 21 mins

2 February 2023 - EVA 6 (US-85): 6 hrs, 41 mins

11 February 2023 - Progress MS-22/83P Docking

11 February 2023 - Progress MS-21 Leak Event

18 February 2023 - Progress MS-21/82P Undocking

26 February 2023 - Soyuz MS-23 Uncrewed docking

2 March 2023 - Prokopyev and Petelin's seat liner moved from Soyuz MS-22 to Soyuz MS-23

3 March 2023 - SpaceX Crew-6 Docking

6 March 2023 - Rubio's seat liner moved from Crew-5 to Soyuz MS-23

11 March 2023 - SpaceX Crew-5 Undocking

15 March 2023 - Thermal test of Soyuz MS-22 by onboard cosmonauts to check how much it will heat up and whether it can be used for emergency evacuation from the ISS in case of any incident

16 March 2023 - CRS SpX-27 Docking

28 March 2023 - Soyuz MS-22 Uncrewed undocking; official switch to Expedition 69

Next: Expedition 69

Crew
Samantha Cristoforetti's mission for ESA on Expeditions 67 and 68 was named Minerva.

Anna Kikina's ride to the station on Crew-5 marked the first time in NASA's Commercial Crew Program that a Russian cosmonaut flew on Dragon, and the first time a Russian (flying for Russia) flew on a US spacecraft in 20 years.

Koichi Wakata's flight to the ISS was his fifth, and his first on Dragon. Combined with his previous flights on Soyuz and the Space Shuttle, he becomes the eighth person to fly on three different Earth-launching spacecraft.