NASA has postponed SpaceX‘s next crew flight until at least next week, as it decides if it wants to bring astronauts currently stationed at the International Space Station back home before launching their replacements.

The US-German crew was scheduled to go to the space station last weekend, but poor weather along the flight path pushed the flight to Wednesday. But then one of the astronauts was sidelined for undisclosed medical reasons, and the launch was bumped to this weekend. SpaceX and NASA called it quits until next week in anticipation of more bad news on the weather front.

NASA said managers will make a final decision soon on whether to prioritize the launch or splashdown of the astronauts currently up there, based on weather. They’re also reviewing how many days would be needed between the two events.

“The weather in November can be especially challenging, so our goal is to move forward on the plan with the highest probability of mission assurance and crew safety,” NASA’s commercial crew program manager, Steve Stich, was quoted by the Associated Press as saying.

The problem in the equation is the amount of time a SpaceX capsule can remain in orbit before its systems are degraded. The company’s Dragon capsules are designed to spend 210 days in orbit. The one currently in orbit logged day 195 on Thursday. Additional analysis could extend the acceptable amount of time, NASA said.

If NASA decides to bring the four astronauts back first, the station will remain occupied by an American and two Russians.

The space agency, meanwhile, is continuing to monitor the “minor medical issue” affecting one of four astronauts awaiting liftoff at NASA’s Kennedy Space Center. NASA said that the astronaut — whom they’re not identifying — should be fine before a possible launch attempt.

(With AP inputs)