Astronomy:Expedition 73

Expedition 73

First-half crew Promotional Poster
Mission type	Long-duration expedition
Operator	NASA / Roscosmos
Mission duration	293 days, 20 hours and 42 minutes (in progress)
Expedition
Space Station	International Space Station
Began	19 April 2025
Ended	9 December 2025
Arrived aboard	Soyuz MS-27 SpaceX Crew-10 Soyuz MS-28 SpaceX Crew-11
Departed aboard	Soyuz MS-27 SpaceX Crew-10
Crew
Crew size	7–11
Members	Expedition 72/73: Anne McClain Nichole Ayers Takuya Onishi Kirill Peskov Sergey Ryzhikov Alexey Zubritsky Jonny Kim Expedition 73/74: Zena Cardman Michael Fincke Kimiya Yui Oleg Platonov Sergey Kud-Sverchkov Sergey Mikayev Christopher Williams
EVAs	3
EVA duration	18 hours, 47 minutes
Expedition 73 mission patch The first half crew, from left to right, top row: Peskov, Kim, Ryzhikov, Zubritsky, and Onishi Bottom row: Ayers and McClain The second half crew, from left to right, top row: Platonov, Kim, Ryzhikov, Zubritsky, and Yui Bottom row: Fincke and Cardman Expeditions

Axiom Mission 4 (black jumpsuits) and Expedition 73 first-half (white jumpsuit) crews

Expedition 73 crew

Expedition 73 is 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 is expected to conclude with the undocking of Soyuz MS-27 on 9 December 2025. It continues the extensive scientific research conducted aboard the ISS, focusing on various fields, including biology, human physiology, physics, and materials science. The crew members also maintain and upgrade 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 has seen two spacewalks so far. 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.

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: 5 hrs, 44 mins

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: 6 hrs, 9 mins

28 October 2025 - EVA 3 (VKD-65) Ryzhikov/Zubritsky: 6 hrs, 54 mins

29 October 2025 - HTV-X1 capture and berthing

27 November 2025 - Soyuz MS-28 docking (planned)

8 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 (planned)

Next mission: Expedition 74

Crew

Flight	Astronaut	Increment 73a	Increment 73b	Increment 73c	Increment 73d
		19 Apr-2 Aug 2025	2-8 Aug 2025	8 Aug-27 Nov 2025 (ongoing)	27 Nov-9 Dec 2025 (planned)
Soyuz MS-27	Sergey Ryzhikov, Roscosmos Third spaceflight	Flight engineer		Commander
	Alexey Zubritsky, Roscosmos First spaceflight	Flight engineer
	Jonny Kim, NASA First spaceflight	Flight engineer
SpaceX Crew-10	Anne McClain, NASA Second spaceflight	Flight engineer		Off station
	Nichole Ayers, NASA First spaceflight	Flight engineer		Off station
	Takuya Onishi, JAXA Second spaceflight	Commander		Off station
	Kirill Peskov, Roscosmos First spaceflight	Flight engineer		Off station
SpaceX Crew-11	Zena Cardman, NASA First spaceflight	Off station	Flight engineer
	Michael Fincke, NASA Fourth spaceflight	Off station	Flight engineer
	Kimiya Yui, JAXA Second spaceflight	Off station	Flight engineer
	Oleg Platonov, Roscosmos First spaceflight	Off station	Flight engineer
Soyuz MS-28 (planned)	Sergey Kud-Sverchkov, Roscosmos Second spaceflight	Off station			Flight engineer
	Sergey Mikayev, Roscosmos First spaceflight	Off station			Flight engineer
	Christopher Williams, NASA First spaceflight	Off station			Flight engineer

Vehicle manifest

Vehicle	Purpose	Port	Docking date	Undocking date
Vehicles inherited from Expedition 72
Progress MS-29	Cargo	Poisk zenith	23 Nov 2024	1 Jul 2025
Progress MS-30	Cargo	Zvezda aft	1 Mar 2025	9 Sep 2025
SpaceX Crew-10 "Endurance"	Exp. 72/73 crew	Harmony forward	16 Mar 2025	8 Aug 2025
Soyuz MS-27 "Favor"	Exp. 72/73 crew	Prichal nadir	8 Apr 2025	9 Dec 2025
Vehicles docked during Expedition 73
CRS SpX-32	Cargo	Harmony zenith	22 Apr 2025	23 May 2025
Ax-4 "Grace"	Visiting commercial mission	Harmony zenith	26 Jun 2025	14 Jul 2025
Progress MS-31	Cargo	Poisk zenith	5 Jul 2025	Dec 2025
SpaceX Crew-11 "Endeavour"	Exp. 73/74 crew	Harmony zenith	2 Aug 2025	April 2026 (Exp. 74)
CRS SpX-33	Cargo	Harmony forward	25 Aug 2025	Dec 2025
Progress MS-32	Cargo	Zvezda aft	13 Sep 2025	Feb 2026 (Exp. 74)
CRS NG-23	Cargo	Unity nadir	18 Sep 2025	March 2026 (Exp. 74)
HTV-X1	Cargo	Harmony nadir	29 Oct 2025	Jan 2026 (Exp. 74)
Soyuz MS-28 "Gyrfalcon"	Exp. 73/74 crew	Rassvet nadir	27 Nov 2025	Jul 2026 (Exp. 74)

Segment	US Orbital Segment				Russian Orbital Segment
Period	Harmony forward	Harmony zenith	Harmony nadir	Unity nadir	Rassvet nadir	Prichal nadir	Poisk zenith	Zvezda aft
19–22 Apr 2025	SpaceX Crew-10	Vacant	Vacant	Vacant	Vacant	Soyuz MS-27	Progress MS-29	Progress MS-30
22 Apr–23 May 2025		CRS SpX-32
23 May–26 Jun 2025		Vacant
26 Jun–1 Jul 2025		Ax-4
1–5 Jul 2025							Vacant
5–14 Jul 2025							Progress MS-31
14 Jul–2 Aug 2025		Vacant
2–8 Aug 2025		SpaceX Crew-11
8–25 Aug 2025	Vacant
25 Aug–9 Sep 2025	CRS SpX-33
9–13 Sep 2025								Vacant
13–18 Sep 2025								Progress MS-32
18 Sep–29 Oct 2025				CRS NG‑23
29 Oct 2025–present			HTV-X1

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.