Michael Alsbury, 39, has been identified as the pilot who died in the crash of Virgin Galactic SpaceShipTwo, and the surviving pilot is Peter Siebold, 43, the Kern County Sheriff's Office said in a statement.
Branson arrived in California's Mojave Desert to meet his Virgin Galactic team and federal officials who were opening their investigation into Friday's accident, the second in less than a week involving a commercial space company.
Virgin Galactic's SpaceShipTwo went down during a powered test flight, scattering debris over 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 news conference in Mojave.
"If we can overcome it, we will make absolutely certain that the dream lives on," he said.
Alsbury, who a sheriff's spokesman said was from Tehachapi, California, was a project engineer and test pilot at Scaled Composites, a Northrop Grumman Corp subsidiary that built and designed the spacecraft for Virgin Galactic.
Siebold was piloting SpaceShipTwo on Friday and Alsbury was serving as co-pilot, Scaled Composites said in a statement.
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 his biography on the company's website.
He was found dead in the aircraft, Kern County Sheriff Donny Youngblood said on Friday.
Siebold parachuted from SpaceShipTwo and was found a mile from the fuselage, Youngblood said. He had moderate to major injuries and was taken by helicopter to Antelope Valley Hospital, the Sheriff's Office said in a statement.
He was alert and talking with his family and doctors on Saturday, the statement from Scaled Composites said. He had been the pilot alongside Alsbury on SpaceShipTwo's maiden test flight last year, according to the company's website.
A team of investigators from the National Transportation Safety Board arrived at the crash site on Saturday to begin piecing together what led to the accident.
"This was a test flight, and test flights are typically very well documented in terms of data," said Christopher Hart, acting chairman of the NTSB. "We may have lots of evidence that will help us with the investigative process," he said.
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.