National Transportation Safety Board (NTSB) Acting Chairman Christopher A. Hart speaks in a press conference on the crash of SpaceShipTwo on Saturday, Nov. 1, 2014 in Mojave, Calif. (AP) - Billionaire Richard Branson is promising to find out what caused the crash of his Virgin Galactic prototype space tourism rocket that killed a test pilot, but federal investigators are cautioning that it may take up to a year to learn exactly what went wrong. The crash in the California desert almost certainly dashed Branson's goal of starting suborbital flight next spring, but the mogul said that while he remained committed to civilian space travel "we are not going to push on blindly." In grim remarks at the Mojave Air and Space Port, where the craft known as SpaceShipTwo was under development, Branson gave no details of Friday's accident and deferred to the NTSB, whose team began its first day of investigation Saturday. He asserted that safety has always been the top priority of the program that envisions taking wealthy tourists six at a time to the edge of space for a brief experience of weightlessness and a view of Earth below. The pilot killed in the test flight was identified Saturday as Michael Tyner Alsbury, 39, of nearby Tehachapi. The surviving pilot is Peter Siebold, 43, who parachuted to safety and was hospitalized. Both worked for Scaled Composites, the company developing the spaceship for Virgin Galactic. Scaled Composite said Alsbury was the co-pilot for the test flight. Siebold, who was piloting SpaceShipTwo, "is alert and talking with his family and doctors," the company said in a statement. A former colleague said Alsbury was a "home-schooled, home-brewed" pilot who earned his way up through the ranks at the company, starting as an engineer. That yesterday ended up in a tragedy was kind of heart-breaking for many of us," said Brian Binnie, another test pilot who worked at Scaled Composites for 14 years before leaving the company this year. National Transportation Safety Board Acting Chairman Christopher A. Hart said investigators don't yet know how Siebold got out of the rocket ship because they haven't had a chance to interview him. He said they found an undeployed parachute at the crash site, He said a 5-mile path of debris over an area of uninhabited desert indicates the spacecraft broke up in flight. Learning where spacecraft parts fell will help investigators determine when and how the breakup occurred. Hart said test flights are usually well-documented. Investigators will review video from multiple cameras that were on the spaceship, on the mother ship, on a chase aircraft and at nearby Edwards Air Force Base. They also have six "nonvolatile" sources of information from the aircraft, and radar data to sift through, he said. The investigation could take up to 12 months to complete, he said. Virgin Galactic - owned by Branson's Virgin Group and Aabar Investments PJS of Abu Dhabi - plans to fly passengers to altitudes more than 62 miles above Earth. The company sells seats on each prospective journey for $250,000. On Saturday, Branson said none of that money has been spent and that anyone who wanted a refund could get it. During other flights, the craft either was not released from its mother ship or functioned as a glider after release. Three people died in a blast at the Mojave Air and Space Port in 2007 while testing a rocket motor for SpaceShipTwo.