MOJAVE, Calif.—Sir Richard Branson knows how to throw a party. And he made sure that the unveiling of his new spacecraft was feted appropriately in a massive hangar here Friday, with pumping music, swirling lights and, of course, champagne.

The ceremony included lofty rhetoric about making space travel accessible to the masses, and the appearance of Star Wars’ Han Solo himself, Harrison Ford, sitting in a front-row seat. But there was also a somber tone. The introduction of the new SpaceShipTwo, christened Unity by Branson’s granddaughter’s milk bottle, came 16 months after its predecessor came apart during a test flight in 2014, killing the co-pilot.

Branson started his speech by saying that his employees “picked themselves up at the end of 2014. They redoubled their efforts and they remain absolutely committed to our shared goal.”

That would be to “make space accessible in a way that has only been dreamt of before now,” he said. “And by doing that we can truly bring positive change to life on Earth."

In an effort to manage expectations and assure potential customers that it was moving deliberately and making safety paramount, Virgin Galactic released a statement the day before the event warning: “If you are expecting SpaceShipTwo to blast off and head straight to space on the day we unveil her, let us disillusion you now: this will be a ground-based celebration.”

First, the new spacecraft would need to go through a series of rigorous tests, the company said. Even before the vehicle was assembled, the company laid out in detail how it “poked, prodded, stretched, squeezed, bent and twisted everything to be used to build these vehicles.”

Once the ground testing is done, it would begin flight testing. Unlike rockets that launch vertically, Unity would be mounted to the belly of a massive mother ship, known as WhiteKnightTwo, an airplane that would fly to more than 40,000 feet. Once aloft, it would drop the spacecraft, which would ignite its engines and fly past the edge of space, where passengers would experience weightlessness and see the Earth from more than 100 km, generally considered the threshold of space.

In a recorded statement played at the event, professor Stephen Hawking said that he has “always dreamed of space flight. But for so many years I though it was just that— a dream. Confined to earth and in a wheelchair, how could I experience the majesty of space except through imagination and my work in theoretical physics?”

He said years ago Branson offered to give him a ride to space, and added that, “I would be very proud to fly in this spaceship.”

Virgin is one of several companies that are working to opening up access to space. founder Jeff Bezos’s Blue Origin also plans to fly tourists to space. (Bezos owns The Washington Post.) XCOR, which is building a suborbital spacecraft that would be able to fly three or four times a day, also hopes to soon fly paying customers past the edge of space. And Elon Musk’s SpaceX and Boeing hold NASA contracts to eventually fly astronauts to the International Space Station.

Perhaps no one, though, knows how to make a splash better than Branson, the founder of the Virgin Group, which includes Virgin Atlantic among many other companies. But after years of delays, and the fatal accident, Virgin Galactic is faced with the delicate balance of promoting its newest spacecraft, and the once unthinkable prospect of routine space travel, against the dangers and difficulties inherent in that endeavor.

Virgin plans on “debuting the first commercial human spaceflight program in history.” And it is clearly eager, after years of delays, to start flying the hundreds of people, including celebrities such as Brad Pitt, Leonardo DiCaprio and Tom Hanks, who spent as much as $250,000 on tickets. But at the same time, it maintains that “this isn’t a race” and that it “won’t cut corners.”

In 2014, the previous version of SpaceShipTwo came apart mid-flight, killing the co-pilot, Michael Alsbury, 39, and injuring pilot Peter Siebold, 43, who ejected at 40,000 feet, and landed on the desert floor after a harrowing descent.

A nine-month federal investigation found that the cause of the crash was a combination of pilot error and the systematic failure to implement basic safeguards. That accident has hung over the program ever since, but Virgin CEO George Whitesides told reporters that, “what I hope you’ll see here today is a sign of resolve…That we are absolutely committed to opening the space frontier, and we’re committed to democratizing space on the road to becoming the world’s first commercial space line.”

In 2004, SpaceShipOne, which was designed by legendary aerospace engineer Burt Rutan, and backed by Microsoft co-founder Paul Allen, won the $10 million Ansari X Prize, when it became the first commercial vehicle to reach the edge of space twice in two weeks. SpaceShipOne now hangs in the Smithsonian’s Air and Space Museum, next to the Spirit of St. Louis.

Just before it won the prize, Branson acquired the rights to the technology behind the spacecraft, and has been working ever since to build next-generation models. The company said it has some 700 customers who have already bought tickets—or more than the total number of people who have ever been to space. And it said it is looking forward to a series of new milestones, including flying a total of eight people on one flight, which has been accomplished only once before—a space shuttle mission in 1985. Another first would be the times it flies the first astronaut from a given nation, it said, adding that “each of these will be exciting milestones in the history of space exploration.”