Russia's space agency will begin charging U.S. astronauts $51 million US per return trip to the International Space Station (ISS) starting in 2012 and resume selling seats to space tourists, according to reports from Russian news agencies.

The United States and other countries, including Canada, will need to use the Russian Soyuz capsule after NASA's space shuttle fleet is retired next year. NASA does not expect to have a replacement spacecraft ready until 2014 at the earliest.

Anatoly Perminov, the head of the Russian space agency Roskosmos, told the Itar-Tass news agency an agreement is in place with the U.S. to charge $51 million, starting in 2012.

It's not known what price they will charge before 2012, but in 2006, Russia charged the United States $21.8 million US per return flight to the ISS. It's also unclear how this would affect astronauts from Canada and Europe who have relied on either the U.S. or Russia to deliver their astronauts to the station.

Perminov also was quoted as saying the agency would once again take civilians — or so-called space tourists — up to the station.

The agency had said in March that U.S. billionaire Charles Simonyi's March flight to the ISS would be the last by a private citizen, as the doubling of the space station crew from three to six would leave no space for civilians.

But Perminov told Itar-Tass the Russian agency has cancelled plans to send a cosmonaut into space in September, leaving open a potential spot for a space tourist.

Simonyi reportedly paid $35 million US for his March trip to the station.