Relief crew for NASA's first medical evacuation splashes down after eight months on the station

Two problems of different kinds set the length of the tour that Jessica Meir, Jack Hathaway, Sophie Adenot and Andrey Fedyaev have just finished ^[3][1]. The first was medical. Fincke's illness brought his crew home early and sent this one up in a hurry ^[6]. The second was mechanical: the capsule repairs that made their relief three weeks late ^[5]. The Guardian's report does not say which capsule needed the work, what was wrong with it, how long NASA had planned the tour to run, or whether the repair had anything to do with the evacuation.

Three weeks is about 9 percent of an eight-month stay, counting a month as roughly 30 days ^[17]. If the slip passed straight through to the return date, the tour would otherwise have run a little over seven months ^[18].

According to the Guardian, the late arrival stalled this crew's homecoming ^[5]. Four people already in orbit waited on a capsule repair. I think that supports a narrow version of the claim that crew rotation runs with little slack. The departing crew's exit was tied to the incoming crew, so a hardware delay turned into extra time in orbit for people who had flown up on short notice. One medical evacuation in 65 years of human spaceflight ^[7] is a rare event, and a capsule repair is a different kind of risk. The thing this doesn't tell you is how often the two coincide.

Once the relief crew had arrived, the return ran to the clock. NASA had scheduled hatch closing for 6:20 a.m. EDT on Oct 7 ^[13]. The hatch closed at 6:05 ^[4], 15 minutes early ^[16], ahead of an autonomous undocking at about 8:05 a.m. ^[4]. The agency had made the undock conditional on spacecraft readiness, recovery-team readiness, Pacific weather off California and other factors ^[14]. Splashdown was targeted for about 11:34 a.m. Eastern on Oct 8 ^[13], and SpaceX brought the capsule down off Los Angeles ^[2]. The post-splashdown briefing that afternoon was set to cover both the Crew-12 return and the SpaceX Commercial Resupply Services-35 launch ^[15].

By NASA's count, the station has hosted 298 visitors from 26 countries since 2000 ^[12]. Before leaving, Meir said the crew had "a lot of mixed, swirling emotions" and would miss the "extraordinary views of our home planet" ^[9]. Minutes after splashdown she said by radio: "We are so excited to be back on Planet Earth after an incredible mission on the International Space Station" ^[8].