Most of us are fortunate enough to have never found ourselves in a life-or-death situation, but many have probably thought about how we would cope if we ever found ourselves in one.

Astronaut Luca Parmitano has revealed exactly what he did when quick thinking saved his life, after his helmet filled with water while he floated outside the International Space Station.

Parmitano was faced with a horrific decision of death by drowning or risking his head exploding during the traumatizing ordeal which was almost sure to take his life in 2013.

On the day in question, the astronaut was due to go on a six-hour spacewalk, but less than an hour into the voyage, disaster struck.

Parmitano began to feel cold water on the back of his head, so he and another astronaut started making their way back to the space station.

Speaking after the incident, as per The Sun, he said: “About half an hour into the EVA [spacewalk], 45 minutes maybe, Chris and I were ahead on our tasks so we were starting our third task and I felt some water on the back of my head.

“I realized that it was cold water, it was not a normal feeling, so I told ground [control]. I started going back to the airlock and the water kept trickling.”

On the journey, however, the water continued to fill the helmet and began covering his face, making it difficult for him to breath and to see.

“It completely covered my eyes and my nose. It was really hard to see. I couldn’t hear anything. It was really hard to communicate,” Parmitano continued.

“I went back using just memory, basically going back to the airlock until I found it.”

Despite the situation quickly deteriorating, he was able to remain calm and feel his way back to the airlock by memory, where his colleagues fought to release his helmet and allow him finally breathe again.

Parmitano recalled a ‘really awful sensation’ as the water began to rise.

“By now, the upper part of the helmet is full of water and I can’t even be sure that the next time I breathe I will fill my lungs with air and not liquid,” he said.

“We are explorers, not colonizers. The skills of our engineers and the technology surrounding us make things appear simple when they are not, and perhaps we forget this sometimes. Better not to forget.”

A similar terrifying incident took place a week earlier, which Parmitano and the team had assumed was caused by a leaky drink bag, however an investigation later revealed a clogged filter to be the cause of the flooding helmets.