The unpiloted Roscosmos Progress 91 cargo spacecraft departed the International Space Station on Sept. 9, 2025, undocking at 11:45 a.m. EDT from the aft port of the station’s Zvezda service module. The vehicle backed away to set up a deorbit maneuver for a destructive reentry, carrying refuse and discarded equipment for disposal.
Undocking and reentry plan
Following the automated separation sequence, Progress 91 is slated to conduct a deorbit burn leading to atmospheric reentry and breakup over a remote area, a standard end-of-mission procedure for the Progress fleet. The spacecraft had been loaded with trash by the crew to remove no-longer-needed items from the orbiting laboratory.
Mission timeline
- Launch: Feb. 27, 2025, on a Soyuz rocket from the Baikonur Cosmodrome, Kazakhstan, delivering about three tons of food, fuel, and supplies.
- Docking: March 1, 2025, after a two-day rendezvous, automatically docking to Zvezda’s aft port.
- Undocking: Sept. 9, 2025, at 11:45 a.m. EDT, to begin deorbit preparations.
Station traffic and port availability
With Progress 91 departed, the Zvezda aft port is now available for future visiting vehicles and station traffic management. At the time of undocking, the station remained served by four docked spacecraft: a SpaceX Dragon cargo craft, the SpaceX Crew-11 Dragon spacecraft, the Soyuz MS-27 crew ship, and the Progress 92 resupply ship.
Why it matters
Regular cargo departures and arrivals are central to maintaining ISS logistics, managing docking port availability, and safely disposing of waste generated during long-duration missions. The Progress 91 campaign supported ongoing Expedition 73 operations and sustained science and maintenance activities aboard the orbital complex.
