The stranded Starliner spacecraft is now delaying SpaceX’s planned Crew-9 mission to the International Space Station (ISS), NASA has announced. The delay, which moves the launch of the Crew-9 mission from Aug. 18 to no earlier than Sept. 24, “allows more time for mission managers to finalize return planning for the agency’s Boeing Crew Flight Test,” NASA wrote in a blog update on Tuesday (Aug. 6). The update has arrived at a fraught time for NASA and Boeing. The Crew-9 members, who are scheduled to replace the current Crew-8 aboard the ISS, cannot arrive at the station until a free docking port opens up. The preferred Harmony module is currently being occupied by the Starliner spacecraft, which has been stuck on the ISS since June. There is still no return date for Boeing’s spacecraft or its astronauts, who have now been on the ISS for months longer than anticipated. Speculation that the beleaguered spacecraft may have to be abandoned is growing. The problems began shortly after Butch Wilmore and Sunita Williams rode to orbit in Boeing’s spacecraft following years of project delays, successfully blasting off on Starliner’s inaugural crewed flight from Florida’s Cape Canaveral Space Force Station on June 5. Related: Fixing Boeing’s leaky Starliner — and returning NASA’s stranded astronauts to Earth — is much harder than it soundsThe astronauts were scheduled to stay a week in orbit, but during the flight, the spacecraft suffered a series of issues, including five helium leaks and five failures of its reaction control system thrusters. This forced engineers to troubleshoot issues on the ground and has extended the two astronauts’ stay aboard the ISS from the planned week to two months and counting.Get the world’s most fascinating discoveries delivered straight to your inbox.NASA engineers say that they are taking more time to pick up data on the flight worthiness of Starliner and to iron out its faults. However, progress toward an eventual flight home has stalled. NASA expected to begin a flight-readiness review for the spacecraft at the beginning of August, but the process has yet to start. Among the reasons for the delay is that Starliner cannot autonomously undock from the ISS, a maneuver that is necessary if NASA decides the craft should return on its own without the astronauts on board, Ars Technica reported. Updating and validating the software needed to make this maneuver will take up to four weeks, sources told Ars Technica. When previously asked about backup plans to return the astronauts without Starliner, Steve Stich, the program manager for NASA’s Commercial Crew Program, said that contingency plans involving SpaceX’s Crew Dragon were in place but that those would be a last resort.”We really have our team focused on, as we close in on this final flight rationale, returning Butch and Suni on Starliner,” Stich said at a July 25 news conference.