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If the Starliner program continues, there may not even be enough time for it to complete its 6 contracted missions: There is a minimum 6-month rotation between SpaceX and Starliner, and it is likely Starliner won’t carry astronauts again until 2026 — but the ISS is scheduled to be retired in 2030.
Citing the Shuttle Challenger and Shuttle Columbia disasters that resulted in the tragic deaths of 14 astronauts, NASA decided that Boeing's troubled Starliner capsule was not safe enough to bring home Suni Williams and Butch Wilmore.
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