Expedition 73 was the 73rd long-duration expedition to the International Space Station (ISS). The expedition began with the departure of Soyuz MS-26 on 19 April 2025 with JAXA astronaut Takuya Onishi taking over the ISS command and concluded with the undocking of Soyuz MS-27 on 9 December 2025. It continued the extensive scientific research conducted aboard the ISS, focusing on various fields, including biology, human physiology, physics, and materials science. The crew members also maintained and upgraded the space station systems.
Background, Crew, and Events The expedition commenced with a crew consisting of NASA astronauts Anne McClain, Nichole Ayers, and Jonny Kim, JAXA astronaut Takuya Onishi, and Roscosmos cosmonauts Kirill Peskov, Sergey Ryzhikov, and Alexey Zubritsky.
The expedition saw three spacewalks. On May 1, 2025, McClain and Ayers performed a 5-hour, 44-minute EVA to install a modification kit on the port side of the station’s truss structure enabling the future installation of its seventh iROSA and relocated an antenna that communicates with approaching and departing commercial crew and cargo spacecraft.
On June 26, 2025, the crew was joined by the staff of Axiom Mission 4's Crew Dragon Grace: commander Peggy Whitson of the United States, pilot Shubhanshu Shukla of India, and mission specialists Sławosz Uznański-Wiśniewski of Poland and Tibor Kapu of Hungary. Their mission marked India, Poland, and Hungary's return to crewed spaceflight for the first time in over 40 years. During their two-week stay aboard the ISS, the astronauts carried out 60 experiments planned by 31 different countries.
SpaceX Crew-11 arrived at the ISS on August 2, transporting NASA astronauts Zena Cardman and Michael Fincke, JAXA astronaut Kimiya Yui, and Roscosmos cosmonaut Oleg Platonov. The mission featured a handover with Crew-10 of six days. Onishi handed over command of the space station to Ryzhikov on August 5. Crew-10 departed with McClain, Ayers, Onishi, and Peskov on August 8.
On October 16, Ryzhikov and Zubritsky performed a 6-hour, 9-minute spacewalk to install the Ekran-M payload onto the Nauka module frame, jettisoned some cameras and a mounting platform, cleaned the windows on Zvezda service module, and removed a SSK panel and a Biorisk container.
On October 28, Ryzhikov and Zubritsky performed a 6-hour, 54-minute spacewalk to install the final set of payloads onto the Nauka module frame the IPI plasma injector into slots two and three, relocate the ERA control panel, clean the Nauka science window, and replace a cassette in the Ekran-M payload.
Soyuz MS-28 arrived at the station on November 27, 2025, transporting NASA astronaut Christopher Williams and Roscosmos cosmonauts Sergey Kud-Sverchkov and Sergey Mikayev.
On December 1, 2025, following the reberthing of Cygnus NG-23 to the Unity module, all eight ISS docking ports were simultaneously occupied for the first time in the station's operation. Cygnus had been temporarily positioned on Canadarm2 on November 24 to clear the approach corridor for Soyuz MS-28 at the Rassvet nadir port. At this time, the station hosted eight visiting vehicles: two SpaceX Dragon 2 spacecraft (Crew-11 and CRS-33), the Northrop Grumman Cygnus XL freighter (NG-23), the JAXA's HTV-X cargo ship (HTV-X1), Roscosmos Soyuz MS crew vehicles (MS-27 and MS-28), and two Progress MS cargo spacecraft (MS-31 and MS-32).
After a handover period, Ryzhikov transferred command of the ISS to Fincke on December 7. The expedition concluded on December 9 with the departure of Ryzhikov, Zubritsky, and Kim aboard Soyuz MS-27.
Events manifest Events involving crewed spacecraft are listed in bold.
Previous mission: Expedition 72
19 April 2025 - Soyuz MS-26 undocking, official switch from Expedition 72 22 April 2025 - CRS SpX-32 docking 1 May 2025 - EVA 1 (US-93) McClain/Ayers: 5hrs, 44mins 23 May 2025 - CRS SpX-32 undocking 26 June 2025 - Axiom Mission 4 docking (Non-Expedition crew) 1 July 2025 - Progress MS-29 undocking 5 July 2025 - Progress MS-31 docking 14 July 2025 - Axiom Mission 4 undocking (Non-Expedition crew) 2 August 2025 - SpaceX Crew-11 docking 5 August 2025 - ISS Expedition 73 change of command from Takuya Onishi to Sergey Ryzhikov 8 August 2025 - SpaceX Crew-10 undocking 25 August 2025 - CRS SpX-33 docking 9 September 2025 - Progress MS-30 undocking 13 September 2025 - Progress MS-32 docking 18 September 2025 - CRS NG-23 capture and berthing 16 October 2025 - EVA 2 (VKD-64) Ryzhikov/Zubritsky: 6hrs, 9mins 28 October 2025 - EVA 3 (VKD-65) Ryzhikov/Zubritsky: 6hrs, 54mins 29 October 2025 - HTV-X1 capture and berthing 24 November 2025 - CRS NG-23 unberthing 27 November 2025 - Soyuz MS-28 docking 1 December 2025 - CRS NG-23 reberthing 7 December 2025 - ISS Expedition 73/74 change of command from Sergey Ryzhikov to Michael Fincke 9 December 2025 - Soyuz MS-27 undocking, official switch to Expedition 74
Next mission: Expedition 74
Crew FlightAstronautIncrement 73aIncrement 73bIncrement 73cIncrement 73d19Apr-2Aug 20252-8Aug 20258Aug-27Nov 202527Nov-9Dec 2025Soyuz MS-27 Sergey Ryzhikov, RoscosmosThird spaceflightFlight engineerCommander Alexey Zubritsky, RoscosmosFirst spaceflightFlight engineer Jonny Kim, NASAOnly spaceflightFlight engineerSpaceX Crew-10 Anne McClain, NASASecond spaceflightFlight engineerOff station Nichole Ayers, NASAFirst spaceflightFlight engineerOff station Takuya Onishi, JAXASecond spaceflightCommanderOff station Kirill Peskov, RoscosmosFirst spaceflightFlight engineerOff stationSpaceX Crew-11 Zena Cardman, NASAFirst spaceflightOff stationFlight engineer Michael Fincke, NASAFourth and last spaceflightOff stationFlight engineer Kimiya Yui, JAXASecond spaceflightOff stationFlight engineer Oleg Platonov, RoscosmosFirst spaceflightOff stationFlight engineerSoyuz MS-28 Sergey Kud-Sverchkov, RoscosmosSecond spaceflightOff stationFlight engineer Sergey Mikayev, RoscosmosFirst spaceflightOff stationFlight engineer Christopher Williams, NASAFirst spaceflightOff stationFlight engineer
Vehicle manifest VehiclePurposePortDocking dateUndocking dateVehicles inherited from Expedition 72 Progress MS-29CargoPoisk zenith23 Nov 20241 Jul 2025 Progress MS-30CargoZvezda aft1 Mar 20259 Sep 2025 SpaceX Crew-10 "Endurance"Exp. 72/73 crewHarmony forward16 Mar 20258 Aug 2025 Soyuz MS-27 "Favor"Exp. 72/73 crewPrichal nadir8 Apr 20259 Dec 2025Vehicles docked during Expedition 73 CRS SpX-32CargoHarmony zenith22 Apr 202523 May 2025 Ax-4 "Grace"Visiting commercial missionHarmony zenith26 Jun 202514 Jul 2025 Progress MS-31CargoPoisk zenith5 Jul 202516 Mar 2026 (Exp. 74) SpaceX Crew-11 "Endeavour"Exp. 73/74 crewHarmony zenith2 Aug 202514 Jan 2026 (Exp. 74) CRS SpX-33CargoHarmony forward25 Aug 202526 Feb 2026 (Exp. 74) Progress MS-32CargoZvezda aft13 Sep 202520 Apr 2026 (Exp. 74) CRS NG-23CargoUnity nadir18 Sep 202524 Nov 20251 Dec 2025 (reberth)12 Mar 2026 (Exp. 74) HTV-X1CargoHarmony nadir29 Oct 20256 Mar 2026 (Exp. 74) Soyuz MS-28 "Gyrfalcon"Exp. 73/74 crewRassvet nadir27 Nov 202526 Jul 2026 (Exp. 74) Segment US Orbital Segment Russian Orbital SegmentPeriodHarmony forwardHarmony zenithHarmony nadirUnity nadirRassvet nadirPrichal nadirPoisk zenithZvezda aft19–22 Apr 2025SpaceX Crew-10 Vacant Vacant Vacant VacantSoyuz MS-27Progress MS-29Progress MS-3022 Apr–23 May 2025CRS SpX-3223 May–26 Jun 2025 Vacant26 Jun–1 Jul 2025Ax-41–5 Jul 2025 Vacant5–14 Jul 2025Progress MS-3114 Jul–2 Aug 2025 Vacant2–8 Aug 2025SpaceX Crew-118–25 Aug 2025 Vacant25 Aug–9 Sep 2025CRS SpX-339–13 Sep 2025 Vacant13–18 Sep 2025Progress MS-3218 Sep–29 Oct 2025CRS NG2329 Oct–24 Nov 2025HTV-X124–27 Nov 2025 Vacant27 Nov–1 Dec 2025Soyuz MS-281–9 Dec 2025CRS NG23 The Prichal aft, forward, starboard, and aft ports all have yet to be used since the module originally docked to the station and are not included in the table.
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