Virgin Galactic has released the final design of the launch system that will take fare-paying passengers into space.
It is based on the X-Prize-winning SpaceShipOne concept - a rocket ship that is lifted initially by a carrier plane before blasting skywards.
The Virgin system is essentially a refinement, but has been increased in size to take eight people at a time on a sub-orbital trip, starting in 2010.
Virgin boss Sir Richard Branson said the space business had huge potential.
"I think it's very important that we make a genuine commercial success of this project," he told a news conference in New York.
"If we do, I believe we'll unlock a wall of private sector money into both space launch systems and space technology.
"This could rival the scale of investment in the mobile phone and internet technologies after they were unlocked from their military origins and thrown open to the private sector."
Virgin Galactic has contracted the innovative aerospace designer Burt Rutan to build its spaceliners. The carrier - White Knight Two (WK2) - is said to be very nearly complete and is expected to begin flight-testing later this year.
SpaceShipTwo (SS2) is about 60% complete, Virgin Galactic says.
SpaceShipTwo under construction in California
Both vehicles are being constructed at Mr Rutan's Scaled Composites factory in California.
The rocket spaceliner will carry two pilot astronauts and six ticketed passengers. They will fly initially from a new facility called Spaceport America in the New Mexico desert.
The journeys will last about two-and-a-half hours from beginning to end.
Passengers on SS2 will climb to an altitude of 110km, from where they will get to experience weightlessness for a few minutes, and see the curvature of the Earth and the black of space.
Seats cost $200,000. Virgin Galactic says more than 200 individuals have booked, and another 85,000 have registered an interest to fly.
Tens of millions of dollars in deposits have already been taken, the company adds.
Sir Richard said the launch system would also be made available to industrial and research groups.
"The fact that this system will have the capability to launch small payloads and satellites at low cost is hugely important," he told the launch event at the American Museum of Natural History.
"As far as science is concerned, this system offers tremendous potential to researchers who will be able to fly experiments much more often than before, helping to answer key questions about Earth's climate and the mysteries of the Universe."
The designs released on Wednesday are a clear evolution of the concept that won the $10m Ansari X-Prize in 2005 for the first successful, privately developed, sub-orbital human launch-system.
Others, such as EADS Astrium, have competing concepts
The most obvious difference is the scale. At 18.3m (60ft) in length, SS2 is twice as big as its predecessor.
Virgin Galactic said in a statement: "It incorporates both the lessons learned from the SpaceShipOne programme and the market research conducted by Virgin Galactic into the requirements future astronauts have for their space flight experience.
"It also has built-in flexibility to encompass future requirements for other scientific and commercial applications."
An SS2 simulator is now available to train the pilots.
WK2 is 23.7m-long (78ft). Its wingspan is unchanged at 42.7m (140ft), but it will now sport four Pratt and Whitney PW308 engines.
Virgin Galactic is one of several companies hoping shortly to offer space trips.
Amazon.com entrepreneur Jeff Bezos has his own scheme, as does the Paypal founder, Elon Musk. Even Europe's EADS Astrium, the company that coordinates the manufacture of the Ariane 5 rocket, is developing a commercial suborbital ship.
Currently, the only way to buy a trip into space is to pay for a seat on the Russian Soyuz launcher. Tickets purchased through Space Adventures cost a reported $20m and take the recipient to the International Space Station for a short holiday.