An American-made spacesuit that leaked water into a helmet and threatened to drown a European astronaut had malfunctioned before.
The flaw appeared during a spacewalk a week before the July 16 outing by Italian astronaut Luca Parmitano, but US space agency officials misdiagnosed it as a leaking drink bag.
That meant the incident, which investigators said was among the most serious in the history of the US space programme, was preventable, Nasa said yesterday in its final report on the investigation into what went wrong.
The fault was attributed to "misdiagnosis of this suit failure when it initially occurred".
Parmitano's helmet began leaking water soon after he began his spacewalk on July 16, and he had 1.5 litres of water in his helmet when he was rescued.