Virgin Galactic, the space exploration company owned by Richard Branson's Virgin Group, has been testing their space tourism spacecraft, and recently have announced a milestone, according to CNN.

The rocket motor that Virgin Galactic had been testing on the ground was fitted into SpaceShip Two, the spacecraft that the company will use to bring the general public into space.

"We lit the rocket motor for the first time in the air and the spaceship went through the sound barrier," Stephen Attenborough, the commercial director of Virgin Galactic, told CNN. "It was a hugely significant milestone for us, and in many ways, the last big piece of the jigsaw."

The trip into space will carry a price tag of $250,000. According to Attenborough, the price is a bargain.

"It's still about one percent of the price you would have needed to pay to go to space as a private citizen before now," Attenborough said.

The space flights aren't set to begin until next year at the earliest, though in spite of that, Virgin Galactic has already sold 640 seats to space enthusiasts wanting to reserve their spot.

The trip into space will consist of three days of training at Spaceport America in New Mexico.

"There's a lot to do with getting you psychologically prepared for a trip that is absolutely about sensory overload," Attenborough said.

Each flight will take six passengers and last for two and a half hours, ending with celebratory champagne at the spaceport. No word on if they serve Dom Perignon. During the flight, space travelers will get to leave their seats so they can experience zero gravity and the expansive view of Earth from space.

"Ultimately, you get memories to last a lifetime - a trip I think will just blow people away," Attenborough said. "When talking to professional astronauts of the past, they don't talk about [their experiences] for a day or a year, they talk about it for the rest of their lives."

Virgin Galactic will bring the general public into space.