A nine-month federal investigation into the fatal crash last year of a Virgin Galactic space ship found that the company hired to build and test the vehicle failed to properly train its pilots and did not implement basic safeguards to prevent the human error that caused the accident.

The National Transportation Safety Board on Tuesday announced that the probable cause of the October crash of a test flight was a mix of human error compounded by systematic failures by Scaled Composites, the company that designed and was operating Virgin Galactic's SpaceShip Two.

The space craft, designed to take paying passengers to the edge of the Earth’s atmosphere, crashed in the Mojave desert, killing the co-pilot, Michael Alsbury, 39, and injuring pilot Peter Siebold, 43, who ejected from the vehicle more than 40,000 feet in the air.

The NTSB had earlier concluded that Alsbury mistakenly unlocked a “feather” system on the space ship that allows two wings to stand upright and create drag on the vehicle. With the wings unlocked prematurely, the space shift broke apart in mid-air, officials said.

But at Tuesday’s hearing, board members focused on the safety culture at Scaled Composites: how it trained its pilots and the systems that could have prevented the pilot from prematurely unlocking the system.

National Transportation Safety Board officials said the pilots at the helm of a Virgin Galactic spaceship that crashed last year were unaware of the consequences of unlocking the craft's moveable tail section too early because of poor training. (Reuters)

It determined that the company “failed to consider and protect against the possibility that a single human error could result in a catastrophic hazard.” And that failure “set the stage for the copilot’s premature unlocking of the feather system.”

The pilots did not wear their full space gear while training in the simulator, the investigation found, and the simulator could not replicate the jolts of high-speed space travel and the increased gravity pressure it causes.

Scaled Composites also did not ensure that “pilots adequately understood the risks of unlocking the feather early,” the investigation found.

NTSB Board Member Robert Sumwalt said that Scaled “put all their eggs in the basket of the pilot doing it correctly.” But he said that humans will inevitably make mistakes, “and the mistake is often times a symptom of a flawed system.”

The investigation also found that the pilots had more tasks to accomplish during the test flight, under tight deadlines, which “increased the opportunity for errors.”

“Each step adds complexity and with increased complexity comes the increased possibility for error,” Sumwalt said.

In a statement, Kevin Mickey, a spokesman for Scaled Composites, which is owned by Northrop Grumman, said that “safety has always been a critical component of Scaled’s culture and, as the NTSB noted today, our pilots were experienced and well-trained.”

He said that the company has “already made changes in the wake of the accident to further enhance safety.  We will continue to look for additional ways to do so.”

Virgin Galactic said in a statement that the company has “already implemented changes as a result of the accident.” Officials said those included an “inhibitor” that would prevent the feather from being prematurely unlocked.

NTSB officials also questioned whether the Federal Aviation Administration, under pressure to issue or deny flight permits in 120 days, rushed Scaled Composites' test flight application without fully vetting it. NTSB investigators interviewed subjects who said there was “political pressure” to issue the permits quickly, but staff members could not say where that pressure came from.

The NTSB recommended that the FAA more thoroughly examine permit applications to make sure they ensure safety.

In response, an FAA spokesman said that the agency takes “all NTSB recommendations very seriously,” and that the agency has 90 days to review them and respond.

The review of the crash comes at a time when commercial space flight has made great strides, moving in a few years from development labs to test flights to real missions under government contracts. In addition to Virgin Galactic, founded by billionaire Richard Branson, several other business tycoons have started commercial space ventures, designed for space tourism, NASA missions and eventually deep-space exploration.

The industry’s boom has been fueled by the likes of Elon Musk, whose SpaceX has won major NASA contracts to fly cargo and eventually astronauts to the International Space Station. Amazon.com founder Jeffrey P. Bezos owns Blue Origin, which plans to fly customers into suborbital space. (Bezos also owns the Washington Post.)

Virgin Galactic, founded by billionaire Richard Branson, has for years promised customers that space flight was imminent but has been repeatedly beset by delays.

Regulators, and Congress, are now scrambling to catch up to the burgeoning industry and figuring out how best to regulate it.

Christopher Hart, the acting chairman of the NTSB, said that the “vision of commercial space travel is close to fulfillment.”

But he added that “the success of commercial space travel depends on the safety of commercial space travel, at the level of every operator and every crew.”