NASA has pinpointed next year as the time when its dependence upon Russia to fly its astronauts to the International Space Station will finally end. However, one of the two companies now slated to provide that service, Boeing, has said it will not be able to launch a crewed mission of its Starliner spacecraft until 2018 at the earliest.

In a report that first appeared in GeekWire, Chief Executive Officer of Boeing’s Defense, Space, and Security Division Leanne Caret told investors: “We’re working toward our first unmanned flight in 2017, followed by a manned astronaut flight in 2018." The company has been struggling to limit the mass of the spacecraft and acoustic issues related to its launch vehicle, a United Launch Alliance Atlas 5 rocket.

After an intense competition with other providers, Boeing received $4.2 billion (~£2.9 billion) in 2014 to finalize development of the Starliner capsule, and SpaceX received $2.6 billion to finish development of its Dragon capsule. A spokesman for SpaceX told Ars Wednesday night that the company remains on track for crewed missions in 2017.

NASA has had to rely on Russian Soyuz spacecraft to deliver its astronauts to the space station since the summer of 2011, when the space shuttle retired. The space agency's administrator, Charles Bolden, has criticized Congress for consistently under-funding its commercial crew program since the shuttle stopped flying. This has already delayed the launch of Boeing and SpaceX vehicles from 2015 to 2017.

The Russians have been reliable partners to NASA in the space station program, but they have steadily increased the price of a seat from less than $50 million several years ago to more than $81.7 million in future years. As a hedge against the possibility of delays, NASA signed a $490-million deal with Russia last year, which would procure six more seats in 2018 and early 2019.