The space tourism industry, despite a slow start amid speculation and doubts, is gaining momentum, an industry conference in New Mexico heard.

Leaders of the commercial spaceflight industry along with officials from NASA and the Federal Aviation Administration were gathering in Las Cruces this week for the seventh annual International Symposium for Personal and Commercial Spaceflight, SPACE.com reported.

"I'm very bullish on the market. We're seeing a lot of activity," said George Nield, associate administrator for commercial space transportation at the FAA. "We're also seeing a real maturity in the industry itself."

British billionaire Richard Branson had predicted in 2004 that his company, Virgin Galactic, would be flying paying customers into space in 2007, and other companies such as XCOR Aerospace, Armadillo Aerospace and Blue Origin soon joined the race.

While none of the firms have yet to launch any paying passengers, they are poised to do so soon, some experts said.

"I'm seeing the likelihood that several of these companies are going to be at the point where they're testing their vehicles in the next couple of years," Nield said. "And certainly within the next five years, I expect to see regular and frequent operations."