NASA is delaying the earliest potential next flight of Boeing Co.’s troubled Starliner spacecraft to 2026, pushing back a key milestone for a vehicle meant to serve as an alternative to the Dragon spacecraft owned by Elon Musk’s SpaceX.

The earliest Boeing's Starliner spacecraft could fly again is early 2026, NASA said on Friday, as it evaluates whether to put humans on board one year after propulsion system issues on the capsule forced its debut crew to stay on the International Space Station for roughly nine months.