NASA trims Boeing Starliner contract, makes last two missions optional

(Reuters) -NASA and Boeing are revising the Starliner spacecraft contract to reduce the number of missions from six to four, the U.S. space agency said in a statement on Monday.

The original $4.5 billion contract, awarded to Boeing under NASA’s Commercial Crew Program, envisioned six post-certification operational flights of the Starliner capsule.

With the latest modification, NASA has designated the remaining two flights as optional.

The Starliner program has been dogged for years by delays, technical faults and cost overruns.

The next Starliner mission will be uncrewed, NASA said, marking the third such test in a development effort that has cost Boeing more than $2 billion since 2016.

Propulsion system issues on the capsule during its most recent mission last year forced its debut c