These days, the story of the early 1990s’ Biosphere 2 may be less well known than that of the 1972 cult film Silent Running, which was one of its inspirations. Like Bruce Dern’s spaceship in the movie, the Biosphere was built to be a sealed environment containing samples of the Earth’s flora and fauna, especially the edible species, fully sustaining a small human crew. Unlike the movie, Biosphere 2 was essentially a giant greenhouse in the Arizona desert rather than domed disks in deep space. (It also wasn’t a sphere: That portion of the name refers to Planet Earth, aka Biosphere 1.)

Biosphere 2 is remembered now mostly as a trendy news story and a failure, neither of which begins to capture its long history and complicated execution, as detailed in the documentary Spaceship Earth. (The doc shares its title with the Epcot sphere because both Biopsphere 2 and the Disney ride were inspired by the work of futurist and ecologist R. Buckminster Fuller.)

Spanning the past 50 years, Spaceship Earth begins 25 years before Biosphere 2 with the development of the cult-like community led by charismatic ecologist John Allen. Funded — we eventually learn — by a friendly billionaire, Allen and his youthful team ran a San Francisco theater company, founded a New Mexico ranch, and built their own sailing ship, a vessel which then allowed them to seed other enterprises throughout the world. Biosphere 2, then, was just another venture, but it captured the public imagination and a glut of media attention in 1991 when eight “biospherians” from different disciplines were locked inside the glass-walled would-be utopia for what was to be two years of biological isolation.

Director Matt Wolf reconstructs this long, complicated history with the help of fresh, frank interviews with most of the participants as well as exhaustive contemporary film footage of the Allen team before and during the Biosphere 2 years. Even the mercurial Allen, who turns 91 on May 6, spoke to Wolf — although his clips cease once Biosphere goes south, suggesting that Allen did not wish to speak about the less flattering aspects of the story.

Indeed, while Wolf does a good job recounting the general sweep of the Biosphere 2 story, Spaceship Earth declines to delve into much scientific detail and treads lightly on the much-reported interpersonal tensions within the Allen team. The film underscores the experiment’s prescient focus on climate change, back when it was called “global warming,” and its undoing in part because corporate interests eventually supplanted the science. (At that point, a young Steve Bannon becomes the villain of the story.)

While you’ll learn more factoids and gossip about Biosphere 2 from Wikipedia than you do from Spaceship Earth, the documentary offers immediacy and direct access to the players, which no merely verbal account can provide. Its snapshot of Biosphere 2’s rise and fall in adoration is fascinating in its by-now familiar media trajectory. The experiment’s messy, drawn-out conclusion, Wolf suggests, blunted its endurance in the public’s consciousness — but not its importance in focusing attention on the planet’s health at a crucial moment.

Grade: B. Not rated, but PG equivalent. Available May 8 from the Fine Arts Theatre’s Virtual Cinema streaming program.

(Photo: Neon)