Work has started on a new Virgin Galactic spaceship after the original craft broke up and crashed on a test flight in October, killing one of its pilots.
The second "SpaceShipTwo" sub-orbital space plane could fly later this year, according to reports.
Virgin chief Sir Richard Branson posted an announcement on Twitter inviting people to "take a look behind the scenes" at the progress being made towards completing the new rocket. Words: PA
Sir Richard said: "We're working towards the vision of creating the world's first commercial spaceline and operating a fleet of vehicles.
"Our second spaceship is being built and tested by our wholly-owned sister organisation, The Spaceship Company, and together we are making any modifications or improvements that we feel are necessary to improve the safety of the vehicle.
"The spaceship is being worked on and will be operated by a strong team of stand-out professionals who are committed to helping us persevere and ultimately succeed."
He added that construction of a third space plane was also due to begin in 2015.
The website spaceflightnow.com reported that the new rocket was "expected to fly later this year".
It said Virgin Galactic, part of Sir Richard's Virgin Group, was aiming to start tourist flights to the edge of space in 2016.
In the Twitter release, Virgin Galactic chief executive George Whitesides said: "We begin 2015 inspired by the words of support we have received from around the world, thankful for our global community of Future Astronauts (Virgin's astronaut corps) who have been so steadfast in their commitment, and proud of our team of over 400 rocket scientists, engineers, designers, and more who have come together to create the world's first commercial spaceline
"Most of all, we remain committed to the goal of opening space to all. 2015 will be an important and exciting year, and we are looking forward to the future."
SpaceShipTwo is designed to reach the edge of space at an altitude of 100 kilometres, or 62 miles, before returning to Earth. More than 700 individuals have signed up to pay around 250,000 US dollars (£163,467) for a ticket.
The original rocket plane broke apart in the air after being released from a carrier jet some 50,000 feet over California's Mojave desert.
Co-pilot Michael Alsbury was killed in the crash. The other pilot, Peter Siebold, escaped with minor injuries after being blown free and parachuting to the ground.
The crash is believed to have involved premature deployment of braking fins that are normally used to aid a safe descent.
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