Safety procedures at Virgin Galactic, whose spacecraft crashed on a test flight last week, had too few safeguards to prevent a potential catastrophe, one of the world’s leading space safety experts has said.

Tommaso Sgobba, a former head of flight safety for the European Space Agency, said industry best practice calls for operators to build in “two-failure tolerance”, or sufficient safeguards to survive two separate, unrelated failures – two human errors, two mechanical errors or one of each. He believes that SpaceShipTwo’s systems fell short of that standard.

According to investigators, Virgin Galactic’s SpaceShipTwo disintegrated after a pilot wrongly unlocked the “feathering” mechanism – which slows the craft during its descent – too early. The mechanism then activated even though the separate lever to deploy it was not pulled. The craft’s co-pilot died in the subsequent crash.