Over its 20-year history, the Martha’s Vineyard Film Festival has built a devoted audience for its annual mix of thought-provoking documentaries, entertaining features and special events, including live appearances by actors, directors and producers.

While its signature program, four days of movies in March, was canceled due to the coronavirus pandemic, the festival is now streaming its opening-night documentary online. Spaceship Earth, about the famous Biosphere 2 experiment in Arizona, is available on demand through the tmvff.org website this week.

“As an opener, we really like to pick something that appeals to a broad base of people, that the Island can get behind and that is of the times,” said festival artistic director Brian Ditchfield. “It became far more of the times than we expected,” he added, laughing.

Biosphere 2, a sealed mini-replica of planet Earth (a.k.a. Biosphere 1) was designed as an experiment in living off the planet. In 1991, eight scientists entered the structure, where they would stay for two years without resources from the outside.

At least, that was the idea.

The reality was more complicated. The plants and animals that had been collected, Noah-like, to populate the biosphere didn’t always thrive, though cockroaches had a population boom. Raising their own food was harder than expected and everyone was hungry all the time. Personality clashes erupted.

And no matter what the scientists did, the carbon dioxide level kept rising in their sealed environment, eventually reaching dangerous levels that required oxygen to be pumped in from the outside.

While the crew stuck out the two-year experiment, billionaire backer Ed Bass grew frustrated and brought in Steve Bannon (wait, what?) to replace the original management team, which some in the media were starting to refer to as a “cult.”

Cult or not, it’s the people behind the experiment who make the documentary more than just an exercise in pop-science history. Construction of the biosphere began in 1987, but the seeds for Spaceship Earth started two decades earlier. In the swirling counter-cultural milieu of 1960s San Francisco, a charismatic Oklahoman named John P. Allen formed the center of a circle of intellectually curious and creative newcomers.

“The cast of characters reminds me of folks you might find here,” Mr. Ditchfield said.

Unlike many of their hippie peers, these young people avoided drugs — though you might not think it from the documentary’s vintage film clips of performances by the group’s Theater of All Possibilities.

Instead of getting high, Allen and his friends got busy, building a ship, sailing the seas, starting businesses around the world and establishing the Buckminster Fuller-inspired Synergia Ranch in New Mexico, where some of them still live. With funding from their own enterprises and much more from Mr. Bass, Biosphere 2 was to be their crowning achievement — proof that humans could manage in a sealed system. But instead of inspiring the world, it became a media sideshow, especially when things started to go wrong.

Still, as the documentary ends on a recent evening at Synergia Ranch, it’s clear that instead of a signal failure, the experiment was just one adventure in the long history of Allen and his friends.

Viewers of the documentary who have questions will be able to ask them May 18 at 7 p.m. when the film festival hosts a teleconference question and answer session with Spaceship Earth director Matt Wolf, producer Stacey Reiss, and Kathelin Gray, one of the original group who went around the world with Allen and then worked on Biosphere 2. Information on how to join the Zoom meeting is posted on the festival website, tmvff.org.

Mr. Ditchfield said the festival will continue to stream films it had programmed for this year, releasing them one at a time through its website and scheduling more sessions with directors, producers and stars.

For children — long an important part of the festival’s audience — there’s the free Movie a Day program, which families can sign up for on the website.

“I’m really proud of what we’re doing for families right now,” Mr. Ditchfield said.

The festival also is living up to its “more than movies” slogan with a free online series of guided meditations with Jake Davis, executive director Hilary Dreyer said. Information is posted at tmvff.org/meditation.