Physicist Stephen Hawking named the new vehicle Virgin Spaceship (VSS) Unity in a recorded speech and on Twitter.
"I would be very proud to fly on this spaceship," Hawking said.
Branson said the new vehicle means space can be made accessible in a way that has only been dreamed about before.
"Our beautiful new spaceship, VSS Unity, is the embodiment of that goal and also a great testament to what can be achieved when true teamwork, great skill and deep pride are combined with a common purpose," Branson said, according to a company press release.
On Thursday, the company said that because of the fatal crash, the new spaceship will not "blast off and head straight to space" anytime soon. Instead, it faces an extensive testing period.
Once the craft has fully checked out, Virgin Galactic plans to use it to ferry passengers up 50 miles above Earth's surface -- a height the company said will qualify them as "bona fide space tourists."
Virgin Galactic released images of its new spaceship.
"One of the things that I think is most powerful is that we'll be able to get a new perspective on our planet as hundreds and eventually millions of people are able to go into space," said George Whitesides, the company's CEO.
More than 700 people have signed up to fly on Virgin Galactic -- even though the company requires $250,000 up front for a seat.
So when will passenger flights begin? The company's tweets and press release are noticeably short on dates. But here are some of the key things that Virgin Galactic said will happen next:
• After the ground tests are done, the spaceship will be flown on the back of its mothership, WhiteKnightTwo.
• Next comes glide testing: The craft flies like a glider from an altitude of 45,000+ feet (8 miles) while pilots test its handling.
• Rocket-powered test flights are next, each flight going a little higher and a little faster. When it crosses 100,000 feet (19 miles), the spaceship will be above 99% of the atmosphere and the pilots will experience weightlessness.
• When it reaches 50 miles (80 kilometers), the pilots will have met NASA and the U.S. Air Force's requirements for official astronaut status, and they will be recognized by the Virgin Galactic team and by the U.S. government as bonafide space travelers.
Virgin released new images of SpaceShipTwo via their Twitter account.
The company said it has made many updates to the craft -- the most important being the feather inhibitor. The plane's feathers are a critical component of its reentry system. The accident that occurred in 2014 was a result of the feathers being prematurely being unlocked.
"The actual accident itself was caused by a control being moved when it shouldn't have," said Dave Mackay, the chief pilot for Galactic. "We've implemented a new system, which prevents that from ever happening again. So it's physically impossible to move that control at the point that it was moved during the accident."
While some of their competitors' ships, such as New Shepard from Jeff Bezos's Blue Origin, don't have pilots and instead rely on automation, Virgin Galactic's system is entirely dependent on the skill of its pilots.
"The pilots are controlling what the vehicle does at any stage," Mackay said. "It's all dependent on the pilot."
Mackay said this strategy was pursed by the company for simplicity: "The responsibility is high. But the reason that we've done it in the first place is to keep everything as simple as possible. The rationale is if you have a simple system, it's less likely to fail, and is therefore inherently safer."
Becoming a member of Virgin's elite pilot corps is no easy feat. Virgin has five pilots, whose resumes all have the "right stuff" -- military, commercial, and test flying experience. Mackay himself has flown over 140 different types of aircraft.
When asked what it takes to be a Virgin Galactic pilot, Mackay said, "We look for the most experienced test pilots that we can get. Test flying is important, because we're in the test and development phase of the vehicle. And we're doing something which is unique. It's very, very unusual."
Virgin's pilots also undergo intense training, using a sophisticated simulator until the spaceship is operational.
And while it will never be quite the same as actually being in space, Mackay said the time in the simulator is extremely valuable: "This is as close as you can get to actually recreating it. You can't simulate the high G forces that we will feel during the rocket motor burn. And of course you can't simulate the extended zero G experience. You couldn't do that in any simulation sort of device. But this is a hugely valuable tool for practicing flying the vehicle, how you operate it, how you operate it efficiently, and how the systems work, and what to do if a particular system or component might fail."
And not only is the simulator work valuable for pilot training, but it also helps with the actual spaceship design process: "A lot of the the work that we've done improving the vehicle, and developing the vehicle is done in the simulator first of all. And then if we like what we've seen in the simulator we incorporate it in the actual vehicle itself."
Even when Virgin Galactic finally takes up its first passengers, it won't be the first time civilians have gone to space. The world's first paying space tourist was American businessman and former NASA engineer Dennis Tito.
Tito flew to the International Space Station in 2001. His ride up? A Russian Soyuz rocket. He paid $20 million for the trip.
Six other people also flew as tourists to the space station.
Now that the new spaceship is closer to flying, the dream of civilian space travel for the non-millionaire crowd is closer to reality.
"It's a significant moment I think in aviation history," said Mackay. "This is the vehicle that is going to take many hundreds of regular people into space for the first time."
