British tycoon Richard Branson insisted today his dream of commercial space travel was still alive though he will first focus on causes of the spacecraft crash that killed one pilot and seriously injured another. Speaking to reporters after arriving in the California facility that had served as the hub of Virgin Galactic's space program, Branson said safety remained his paramount concern. "We owe it to our test pilots to find out exactly what went wrong, and once we've found out what went wrong, if we can overcome it, we'll make absolutely certain that the dream lives on," a grim-faced Branson told reporters. "We do understand the risks involved, and we're not going to push on blindly," he said. "To do so would be an insult to all those affected by this tragedy. "Safety has always been our number one priority," he added before heading off to rally grieving Virgin Galactic staff. Branson's comments at the Mojave Air and Space Port came as a team of federal investigators began probing the causes of yesterday's accident, which dealt a devastating setback to the cause of commercial space tourism. National Transportation Safety Board (NTSB) acting chairman Christopher Hart told reporters that investigators were entering unknown territory but hoped to find clues to the accident in data gathered by Virgin Galactic. "This will be the first time we have been in the lead of a space launch that involved persons on board," Hart said. It was not immediately known if a black box flight data recorder was installed on the doomed suborbital craft, though Hart stressed that test flights are usually documented with significant amounts of data. Branson headed to California within hours of the crash, which saw the company's suborbital SpaceShipTwo break apart and hurtle to the ground shortly after it had detached from a mothership at an altitude of around 45,000 feet (13,700 meters) during a test flight. The Los Angeles Times identified the pilot killed in the crash as 39-year-old Michael Alsbury, a father of two. The crash was the second disaster to rock the private space industry in the space of a few days, after an Antares rocket carrying supplies to the International Space Station exploded after take-off in Virginia in Tuesday. Experts say the accident will delay the advent of commercial space tourism by several years. Virgin Galactic had hoped to start ferrying wealthy customers to the edge of space in 2015, charging $250,000 per person for a ticket on the company's six-seater vehicle. Around 500 people, including a slew of celebrities such as Hollywood star Leonardo DiCaprio, had already reserved tickets on the first wave of Virgin Galactic flights, according to reports.