MOJAVE, Calif. - The bullet-shaped spacecraft is the size of a large business jet - with wide windows and seats for six (well-heeled) passengers to take a ride into space.

It's billed as the world's first commercial spacecraft, designed to be carried aloft by an exotic jet plane before firing a rocket engine to climb beyond Earth's atmosphere.

Yesterday, Virgin Galactic unveiled SpaceShipTwo, which had been under secret development for two years.

The company plans to sell suborbital space rides on the craft for $200,000 a ticket, offering passengers 21/2-hour flights that include about five minutes of weightlessness.

"We want this program to be a whole new beginning in a commercial era of space travel," said Virgin Galactic founder Sir Richard Branson, who has partnered with famed aviation designer Burt Rutan on the venture.

The British billionaire hopes to begin passenger flights out of New Mexico some time in 2011 after a series of rigorous safety tests. Branson said he, his family, and Rutan would be the first to fly on SpaceShipTwo.

The white, stubby-winged spaceship sat in a Mojave Desert hangar, attached to the jet that will carry it to launch altitude.

Later yesterday, California Gov. Arnold Schwarzenegger and New Mexico Gov. Bill Richardson were to christen the ship "Enterprise."

SpaceShipTwo is based on Rutan's design of the prototype SpaceShipOne. In 2004, SpaceShipOne captured the $10 million Ansari X Prize by becoming the first privately manned craft to reach space.

Since that historic feat, engineers from Rutan's Scaled Composites L.L.C. have been laboring in the Mojave Desert on a larger model suitable for commercial use.

Some 300 clients already have paid for the $200,000 ticket or placed a deposit, according to Virgin Galactic.

The last time there was this level of hoopla in the high desert was a little more than a year ago when Branson and Rutan trotted out to great fanfare the twin-fuselage mother ship, White Knight Two, that will carry SpaceShipTwo.

Despite the hype, hard work lies ahead before space journeys could become as routine as air travel. Flight testing of White Knight Two has been going on for a year.

SpaceShipTwo, built of lightweight composite materials and powered by a rocket, is similar to its prototype cousin with three exceptions.

It's twice as large, measuring 60 feet long with a roomy cabin about the size of a Falcon 900 executive jet. It also has more windows, including overhead portholes. And while SpaceShipOne was designed for three people, SpaceShipTwo can carry six passengers and two pilots.

After reaching the top of its trajectory, the craft will fall back into the atmosphere and glide to a landing like an airplane.

Space travel has been limited so far to astronauts and a handful of wealthy people who have shelled out millions to ride Russian rockets to the International Space Station.

Virgin Galactic is not the only player in the commercial space race. Other entrepreneurs, including Amazon.com Inc. chief executive Jeff Bezos, computer-game programmer John Carmack, and rocketeer Jeff Greason also are building suborbital rockets.