US safety officials on Tuesday accused the builders of a commercial space vehicle of failing to factor in human error that caused its disintegration over the Mojave Desert last year.

The National Transportation Safety Board said the deadly crash could have been avoided if Scaled Composites, which built the vehicle for Virgin Galactic, had anticipated potential piloting mistakes and installed systems to avert the premature brake deployment that downed the SpaceShipTwo.

The pilot was injured but successfully deployed his parachute, while the co-pilot was killed. Both men were employees of Scaled Composites, a subsidiary of US group Northrup Grumman.

The October 31 accident delayed the space-tourism goals of British billionaire Richard Branson, owner of Virgin Galactic, as he prepared to transport the first paying customers to the edge of space more than 62 miles (100 kilometers) above Earth.

The NTSB determined that the co-pilot prematurely unlocked the spacecraft's braking operation, known as a feather system, resulting in "catastrophic structural failure."

SpaceShipTwo, after being released from a four-engine rocket to about 50,000 feet (15,000 meters), engaged its engine to reach its desired altitude of 109 kilometers.

But the co-pilot activated the brake system too early during the boost phase of the flight, at 0.8 Mach instead of the desired 1.4 Mach, according to NTSB, confirming preliminary findings.

- 'New frontier' -

NTSB member Robert Sunwalt said that the "failure of Scale Composites to consider the possibility that the effects of a single human error would cause the feather to extend," and to fully inform the pilot about risks of early unlocking of the feather system, contributed to the accident.

"Manned commercial spaceflight is a new frontier, with many unknown risks and hazards," NTSB Chairman Christ Hart added.

"In such an environment, safety margins around known hazards must be rigorously established and, where possible, expanded."

The NTSB said it made recommendations to the Federal Aviation Administration and Commercial Spaceflight Federation (CSF) that would establish "human factors guidance" for commercial space operators and promote stronger collaboration between the FAA and commercial space vehicle operators.

"We cannot undo the unfortunate events that transpired last October," CSF president Eric Stallmer said in a statement.

"But we will successfully apply, and in some cases have already applied, the lessons learned to make our entire industry better and safer as a result."

Virgin Galactic is currently building a new spacecraft. Company officials indicated in May they hoped to resume test flights this year.

The new craft may one day carry six passengers on three-hour suborbital flights, offering them the possibility of momentary weightlessness and unparalleled views of Earth.

In May 2014, the company obtained the green light from the FAA to launch flights from a base in New Mexico dubbed "Spaceport America."

The astronomical $250,000 ticket price has proven no barrier for more than 600 candidates, including celebrity actors Leonardo DiCaprio and Ashton Kutcher.