From left, Jane Poynter, Linda Leigh, Mark Van Thillo, Taber MacCallum, Roy Walford (in front), Abigail Alling, Sally Silverstone and Bernd Zabel in “Spaceship Earth.” (Neon)
Movie critic

Rating: (3.5 stars)

“The future is here,” says one of the eight intrepid explorers who in 1991 walked into the sprawling three-acre greenhouse known as Biosphere 2, for a two-year experiment in ecology and self-containment (not to mention interpersonal psychology and power dynamics).

Don’t you know it, sister. “Spaceship Earth,” Matt Wolf’s engaging documentary about a ragtag group of idealists who set out to explore the world — and then save it — couldn’t be better timed: The film’s distributor, Neon, is making it available on streaming because, really, what could be more relevant to the coronavirus lockdown than a chronicle of the 20th century’s most famous self-quarantine?

People who remember the press hysteria surrounding Biosphere 2 might think of it as a spectacular flop, the utopian promise of its mission sullied by media spectacle and a few cheats along the way. Eventually treated like a human diorama by the tourists who traveled to peer at them through the glass triangles of their quarters, the terrestrial astronauts (terranauts?) who volunteered to sequester themselves in a collection of seven mini-biomes were tarred as a naive cult at best, and charlatans at worst.

“Spaceship Earth” helpfully deconstructs those accusations, first by delving into the project’s origins in 1960s San Francisco, when a charismatic Oklahoma transplant named John Allen gathered a group of bookish, artistically inclined young people to get things going, whether in the form of experimental plays, a farm in New Mexico or an oceangoing ship that they built from scratch in Oakland, Calif. After sailing the world, learning about global warming and attracting the attention and money of oil scion and environmentalist Ed Bass, Allen hit upon the idea of launching an earthbound test of what might eventually be a colony on Mars or the moon.

Luckily for us, Allen and his colleagues were compulsive recorders of their adventures, and one of the Biospherians, a physician named Roy Walford, brought a video camera into the complex. With a wealth of archival material to work with, Wolf does a superb job of sending viewers back into the 1980s and 1990s — whose scratchy, juddering VHS-era production values and “Galaxy Quest”-worthy uniforms might be tough on the eyes, but are note-perfect in conjuring the time period. He also interviews as many surviving participants as he can, giving “Spaceship Earth” a welcome note of self-awareness and perspective (although no one addresses the conspicuous homogeneity of the group). Anyone who fears going stir crazy at a time when going to the store is more akin to scrubbing in for surgery than running a light errand will relate when tensions rise and systems begin to break down; if the Biospherians’ two-year sojourn in the Arizona desert proved anything, it might be just how much a whiff of fresh air can do.

There’s a third-act twist involving a present-day political figure that is so shocking, and strangely prescient, that divulging the details wouldn’t be sporting. Suffice it to say that, in addition to celebrating the energy, enterprise and idealism of America’s postwar generation, “Spaceship Earth” provides a sobering primer in how some dreams die, and others are strangled mercilessly in their cribs.

Unrated. Available May 8 via streaming at theavalon.org, sunscinema.com, afisilver.afi.com and cinemaartstheatre.com. Contains brief coarse language. 115 minutes.