CAPE CANAVERAL, Fla. (AP) — Boeing and NASA have agreed to keep astronauts off the company’s next Starliner flight and instead perform a trial run with cargo to prove its safety.

NASA also is slashing the planned number of Starliner flights, from six to four. If the cargo mission goes well, then that will leave the remaining three Starliner flights for crew exchanges before the space station is decommissioned in 2030.

“NASA and Boeing are continuing to rigorously test the Starliner propulsion system in preparation for two potential flights next year,” Steve Stich, NASA’s commercial crew program manager, said in a statement.

NASA hired Boeing and SpaceX in 2014 — three years after the final space shuttle flight — to ferry astronauts to and from the orbiting outpost. The Boeing contract was worth $4.2 billion and SpaceX’s $2.6 billion.

Elon Musk’s SpaceX launched its first astronaut mission for NASA in 2020. Its 12th crew liftoff for NASA was this summer.