The $4.5 billion five-year contract by NASA to Boeing to develop a 'space taxi' to ferry US astronauts to the International Space Station (a $100 billion research complex that flies about 260 miles or 418 km above Earth) will also include a seat for paying tourists.

Russian space agency already charges tourists to fly to orbital outpost. But now, Boeing Commercial Crew Program Manager John Mulholland told that under the contract, there would be a competitive price by Boeing to sell space ride to tourists. Boeing's first test launch of the taxi is not expected until 2017.

Mulholland said, "Now that Boeing has won a share of NASA's space taxi contract. We hope to start working with the ISS program to make it happen. We think it would be important to help spur this industry".

Virginia-based Space Adventures has been organizing trips to the space station aboard Russian Soyuz capsules for more than a decade. The next space tourist, British singer Sarah Brightman, is due to travel to the space station for 10 days next year. Space Adventures' president Tom Shelley says the trip will cost $52 million.

Boeing faces competition from rival Space Exploration Technologies, or SpaceX, which also won a NASA contract. SpaceX claims that it can develop the taxi for nearly 40% less than Boeing.

SpaceX already plans to offer trips to tourists, but did not immediately respond to questions about whether it would fly tourists on its NASA missions.

Since the retirement of the space shuttle in 2011, the United States has been booking rides on Russian Soyuz flights, which is expected to continue through 2017. NASA relies on Russian rockets and capsules to fly U. S. astronauts to and from the space station.

The price tag has climbed to about $70 million a seat, which made U. S. policy makers and lawmakers worry about continued dependence on them. Now, NASA's commercial spaceflight program is making steady progress. However, Boeing's first test launch of the taxi is not expected until 2017.