U.S. astronaut Karen Nyberg, left, trains with a Russian and an Italian colleague for a trip to the international space station. (Yuri Kadobnov/Agence France-Presse via Getty Images)

The ticket price for flights into space is going up. NASA, the U.S. space agency, has agreed to pay $424 million to Russia to carry U.S. astronauts into space.

NASA announced its latest contract with the Russian Space Agency last week. The $424 million will pay for flights to and from the international space station aboard Russian Soyuz spacecraft for six astronauts in 2016 and the first half of 2017.

That’s $70.6 million per seat, up from the old rate of about $65 million.

Russia provides the only way of getting people to and from the space station, and its prices have soared recently.

Several companies are working on rockets and spacecraft to launch Americans from the United States. But that remains a few years away. NASA’s ability to send crews into orbit ended with the closing of its shuttle program in 2011. Even before then, the United States had been relying on Russia to take some astronauts to the space station.

SpaceX has begun making cargo shipments to the space station. Its founder, Elon Musk, has said the California-based company could be ferrying astronauts by 2015. Orbital Sciences of Virginia plans to start sending supplies to the space station this summer, but it has no interest in carrying passengers.