ORLANDO, Florida, Jan 30 (Reuters) - The vice president

leading Boeing's ( BA ) Starliner spacecraft unit, Mark Nappi,

has left his role in the program and been replaced by the

company's International Space Station program manager, John

Mulholland, a Boeing ( BA ) spokesperson told Reuters on Thursday.

Nappi, who led Boeing's ( BA ) Starliner program from 2022 through

major engineering issues and testing mishaps, is currently in a

new role "focused on identifying opportunities for streamlining

improvement across the division's space programs until he

retires next month," the company said.

Mulholland previously led Boeing's ( BA ) Starliner program from

2011 before switching in 2020 to the company's International

Space Station program, which works closely with NASA under a

multibillion-dollar station operations contract.

Boeing's ( BA ) Starliner spacecraft, in development under a $4.5

billion NASA contract to ferry astronauts to the ISS, has faced

an array of engineering challenges since 2019.

In its first test mission last summer flying astronauts,

Starliner was forced by NASA to leave its crew aboard the ISS

and return empty in September over problems with its propulsion

system.

A panel of senior NASA officials in August had voted to have a

Crew Dragon capsule from Elon Musk's SpaceX bring them back

instead, deeming Starliner too risky for the astronauts.

Paul Hill, a veteran NASA flight director and member of the

agency's Aerospace Safety Advisory Panel, said during a

quarterly panel meeting on Thursday that NASA and Boeing ( BA )

continue to investigate Starliner's propulsion system.

A Boeing ( BA ) spokesperson said on Thursday that the company and

NASA have not yet determined what Starliner's next mission will

look like, such as whether it will need to repeat its crewed

flight test before receiving NASA certification for routine

flights.

NASA's decision in August to have Starliner come back empty and

leave its astronauts on the ISS for months longer than planned

was a bruising moment for Boeing's ( BA ) space unit, as SpaceX's Crew

Dragon capsule dominates the private spaceflight business.