Enormous structures built of steel and glass, protecting their occupants from the infinite vacuum outside. Housed within are the flora and fauna of planet Earth, improbably situated on some alien surface.  A testament to human ingenuity, the final conquering of the cosmos’ final frontier: such are the images conjured when we imagine extra-terrestrial colonies on the moon, Mars, or further.

It’s the stuff of science fiction, but in the 1980s and early 1990s a group set out to build just such a structure. Not in space, mind you, but in the Arizona desert. In his latest documentary Spaceship Earth, Matt Wolf tells the story of the project and the team that devised it. Part scientific research project, part environmental publicity stunt, Biosphere 2 (Biosphere 1 being Earth itself) was designed to be entirely self-contained and airtight, mimicking the natural environments of the planet while being entirely self-sustaining.

The ultimate plan was for a team of scientists to live in the facility for two years, breathing only the oxygen providing by their plants, eating only what they grew and farmed themselves, recycling everything back into the system in a continuous cycle. In short, a miniature Earth that would demonstrate its bigger sibling’s fragility as well as our capacity to exist sustainably and harmoniously within a closed system.

Astonishingly, the project was realised in 1991 and a team of eight ‘biospherians’ really did seal themselves inside for two years, with only a couple of cheats. The glimpses we get of their two years inside are thrilling, even awe-inspiring. The structure itself, aptly described by the researchers as a new Eden, is an astonishingly beautiful, strange creation. The 90s-era analogue archival footage that depicts Biosphere 2 feels both quaint and monumental, evoking the grand imagination and grainy aesthetics of the era’s ubiquitous TV science fiction.

Alarm bells ring, however, amidst the charisma of leader John Allen and the hippy commune-lite practices of his group. Indeed, the reality of Biosphere 2 was less than cosmically inspiring: contemporary interviews reveal a fascinating and enduring pride in the group’s corporatist features and a rather telling denial that they lived as a commune in the early days of the 1970s. Perhaps most interestingly is the acceptance among that group that they were cult-like, who argue that all innovators look like cult leaders before they change the world. Amidst contemporary media criticism and sensationalism of the project, there’s a light refusal here to cast the scientific and ethical merits of Biosphere 2 as a binary proposition, and one gets the impression that Wolf himself is ambivalent about the endeavour and its inevitable compromises.

Sadly, that ambivalence accompanies a rather unsatisfying shallowness of historical scrutiny. Hints of Allen’s megalomania are left at just that, while we’re barely given time to get over the shock of the last-minute appearance of a sinister political figure before the credits roll. Still, Spaceship Earth deftly captures the sincere wonder and optimism of those who believed in the project. There’s simply no denying the sheer ambition of the damn thing, let alone that they more or less pulled it off.

Matt Wolf’s Spaceship Earth is available on demand from 10 July. spaceshipearthfilm.co.uk

Christopher Machell @MachellFilm