Breathing air provided by algae soaked in his own urine, "aquanaut" Lloyd Godson spent 12 days living in a yellow steel capsule submerged in a flooded gravel pit.
The 29-year-old's claustrophobic ordeal was intended to shed light on the practical and psychological challenges of living in an alien environment.
The 'world's first self-sufficient, self-sustaining underwater habitat'
His temporary home, a 10ft long box, was billed as "the world's first self-sufficient, self-sustaining underwater habitat." Back on dry land, and toasting the success of the experiment with champagne, he admitted to suffering cabin fever.
"It starts to play on your mind a bit after 12 days obviously. You start to get a bit of cabin fever, but you know I handled it surprisingly well. I thought it was going to drive me a bit more nuts than it did."
"It's nice to feel the sunshine on the face and the breeze," Godson said after surfacing from the quarry near Albury, in New South Wales.
The marine biologist used a system of onshore solar panels and a pedal-powered generator to create electricity and recharge his water-proof laptop computer.
He kept an algae garden to absorb carbon dioxide and release oxygen for breathing.
A team of divers delivered food and drinking water to the sub through a manhole, including a homemade lasagna and freshly barbecued salmon.
Now, if we can just assure that Domino's is able to reach the Mars Mission spacecraft at every point along its journey to and from the Red Planet....