The pilot who survived the disintegration of Virgin Galactic’s spaceship said he didn’t know that his co-pilot had unlocked the brakes too early, sending the craft into its death spiral, federal investigators said.

Protocol calls for the co-pilot to announce the step, but an SFGate report states that didn’t happen, pilot Peter Siebold told the government. Mike Alsbury, the co-pilot, died in the crash over the Mojave Desert.

Virgin Galactic had hoped SpaceShipTwo would pioneer the first tourist trips to space. Company officials are adamant they will continue their mission despite the risks.

SFGate reported that it wasn’t immediately clear whether the brake unlocking miscommunication was a matter of Siebold not hearing Alsbury or because the interaction never happened in the first place, but the National Transportation Safety Board will examine the audio soon.

Investigators will further need to determine what caused the crash, as the brakes have to be applied after they are unlocked — which is what investigators believe caused the aircraft to endure enormous stress and break apart.

Typically, pilots and co-pilots in space programs engage in “challenge and response” systems to ensure proper communication by having one voice an intended action and the other repeat it back in confirmation. This would take place even during routine operations on commercial airliners.

Virgin Galactic hopes that tests will eventually lead to launching a spacecraft with six passengers from a New Mexico spaceport at an eye-popping price tag of $250,000 per ticket. For those that can afford it, that ticket would buy them the experience of weightlessness and a view of Earth 62 miles off the ground.

Although Siebold was hospitalized for his injuries, he was discharged by the time he spoke to investigators. He said he had been thrown from the spacecraft as it broke apart and his parachute deployed automatically.