Space Adventures, the private firm that sent seven paying clients on trips to the International Space Station (ISS) between 2001 and 2009, will have three more seats available for tourists to fly to the outpost starting in 2013, the company announced in a January 12 press release.

As with past Space Adventures trips to the ISS, the newly available seats will be on Russian Soyuz spacecraft. Extra space on the Soyuz had grown scarce lately—the ISS crew size doubled to six in 2009, and NASA will be reliant on Russian rockets to ferry astronauts to and from the station after the space shuttle is retired, which is expected to happen later this year. But according to the press release, an increase in Soyuz production will allow Space Adventures to offer more tourist flights in cooperation with the Russian space agency Roscosmos and Russia's Energia Rocket and Space Corp.

"There's no set figure" for how much the seats will cost, Stacey Tearne, vice president for communications at Virginia-based Space Adventures, told Scientific American, adding that the price will depend on the timing of the purchase and the particulars of the trip. The most recent clients have paid about $30 million to $35 million, and Tearne said new clients will probably pay somewhat more than that.

Photograph of Cirque du Soleil founder Guy Laliberté, the most recent Space Adventures client to fly to the ISS, on board the station in 2009: NASA