Virgin Galactic could have a new spacecraft ready to fly by next year, the chief executive of Richard Branson's space tourism company said in an interview published on Sunday, reacting to concerns about the safety of technology used in the Virgin craft that crashed last week.

George Whitesides, the head of the company dedicated to Branson's vision of bringing everyday passengers into space, told the Financial Times the new fuel system used in Virgin's SpaceShipTwo during Friday's test flight in the Mojave Desert was rigorously tested. One pilot was killed and the other badly injured in the crash.

Whitesides said a second craft being built for Virgin was about 65 percent complete, sounding a note of optimism about the program even as federal investigators were just beginning what is likely to be a year-long investigation into accident.

"The second spaceship is getting close to readiness," he said, adding that it could be ready to fly by next year once the probe by the National Transportation Safety Board reached its conclusions.

His remarks followed a somber assessment of the future of Virgin Galactic by founder Branson, who hoped to be among the first passengers on its maiden voyage that had been expected early next year.

"We really thought by March of next year, we'd be there," the billionaire entrepreneur told the BBC after arriving in Mojave on Saturday. "Something went wrong. We need to find out what went wrong and fix it."

U.S. investigators say the powered test flight of Virgin's SpaceShipTwo on Friday was well recorded, giving them an abundance of information to help determine what caused it to crash and spread debris over a 5-mile (8 km) swath of the Mojave Desert, 95 miles (150 km) north of Los Angeles.

"We owe it to our pilots to find out exactly what went wrong," Branson said during a Saturday news conference in Mojave. "If we can overcome it, we will make absolutely certain that the dream lives on."

Michael Alsbury, 39, has been identified as the co-pilot who died in the crash of SpaceShipTwo, and the surviving pilot is Peter Siebold, 43.

Alsbury, who police said was found dead in the aircraft and who resided in Tehachapi, California, was a project engineer and test pilot at Scaled Composites, a Northrop Grumman Corp subsidiary that built and designed the craft for Virgin Galactic.

Alsbury was flying for the ninth time aboard SpaceShipTwo, including serving as the co-pilot on its first rocket-powered test flight on April 29, 2013, according to the company's website.

Siebold parachuted from SpaceShipTwo and was found with serious injuries by rescuers, who took him by helicopter to Antelope Valley Hospital, the Kern County Sheriff's Office said in a statement.

He was alert and talking with his family and doctors on Saturday, Scaled Composites said in a statement.

An aircraft flying behind SpaceShipTwo collected video images and radar data, and a range camera at Edwards Air Force Base also recorded the failed test flight, Hart said. The spaceship had video cameras and data storage cards on board which could help investigators.

Friday's crash was the second disaster in less than a week suffered by a private space company, dealing a blow to the fledgling commercial space industry that has been taking on work traditionally done by governments.

On Tuesday, an Antares rocket built and launched by Orbital Sciences Corp exploded after liftoff from Wallops Island, Virginia, destroying a cargo ship bound for the International Space Station.

New Type of Fuel

The Virgin probe will likely focus on SpaceShipTwo's rocket engine, which on Friday was flying with a new type of fuel for the first time, experts said.

The solid plastic-type propellant is ignited by liquid nitrous oxide, commonly known as laughing gas.

Virgin Galactic announced in May it was replacing the rubber-based propellant used during the spaceship's three previous rocket-powered test flights to get better performance.

Before Friday's flight, SpaceShipTwo's last powered test flight was in January, though the rocket and its new propellant had passed multiple ground tests.

"We have put that motor through a rigorous ground development program," Whitesides said in the FT interview. "The results of those tests were positive."

Virgin Galactic is a U.S. offshoot of the London-based Virgin Group founded by Branson, one of the world's most famous entrepreneurs whose empire ranges from airlines to music stores and mobiles phones.

Friday's accident marked the fourth fatality in Scaled's SpaceShipTwo development effort. In 2007, a fuel tank exploded, killing three Scaled employees.

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