"The proposal was sent to NASA a few days ago," he was quoted by Interfax as saying.

No one could be reached at Rosaviakosmos to comment late Friday night.

The space station has been limited to two full-time residents since last year's suspension of the U.S. space shuttle program in the wake of the Columbia disaster, which left Russia's three-man Soyuz rocket as the only vehicle to take astronauts to and from the station.

Currently, two Soyuz rockets blast off every year at six-month intervals. They have been carrying the space station's two-man replacement crew and a temporary visiting astronaut. The visiting astronaut typically stays for just over one week then heads back to Earth with the station residents whose six-month stay is up.

Gorbunov said that if the missions on the station were extended to one year, one of the Soyuz flights could be used to carry up two paying customers -- earning the cash-strapped Russian space program much needed funds.

"The money that Russian received from flying European astronauts and space 'tourists' was invested in the space station program in addition to the budget money," Gorbunov was quoted as saying. "Now with the absence of the shuttle, those means are reduced."

"The opportunities for (the Russian space) agency to earn additional money have dramatically declined," he was quoted as saying.

Russia's temporarily froze its space tourism program -- which reportedly earned the agency US$20 million a flight -- after the shuttle disaster.

Russia's space agency has repeatedly complained that it is hard-pressed financially to continue shouldering the burden of all flights to and from the space station in the absence of the U.S. shuttle. The shuttle had been the primary ferry to the station before the Columbia accident, leaving Russia's Soyuz to focus more on commercial trips.

Gorbunov said that Russia hoped to receive an answer from NASA within the next two to three weeks, Interfax said.