Space Adventures says it's planning to expand the living space available on its planned tourist trip around the moon.
The company says it's adding a second habitation module to the Soyuz TMA lunar complex. The extra module would launch with the Block DM propulsion module and rendezvous with the Soyuz spacecraft in low-Earth orbit.
"Space Adventures will once again grace the pages of aerospace history, when the first private circumlunar mission launches. We have sold one of the two seats for this flight and anticipate that the launch will occur in 2015," says vice-chairman of Space Adventures Richard Garriott.
"Having flown on the Soyuz, I can attest to how comfortable the spacecraft is, but the addition of the second habitation module will only make the flight that more enjoyable."
As part of a market sizing exercise for NASA's Commercial Crew Development bid, submitted on behalf of the Boeing Company, Space Adventures estimates that by 2020 around 140 more private individuals will have launched to orbit.
Destinations would include the International Space Station, commercial space stations and orbital free-flys.
"The next 10 years will be critical for the commercial spaceflight industry with new vehicles and destinations coming online," says Anderson.
"But in order to truly develop the industry and extend the reach of humanity over the course of time, there will need to be breakthrough discoveries made and innovative propulsion systems designed that will bring the solar system into our economic sphere of influence."
Space Adventures is planning to offer three ten-day trips to the ISS next year, at a price of around $35,000 a head.