I mean, Biosphere 2 failed because it was started by a cult that mismanaged the shit out of it, then Steve Bannon took over and outright killed the company. A lot of the really crazy shit that happened was a result of corporate power struggles. The first Biosphere experiment lasted two years and is considered overall a success, probably because Steve Bannon wasn’t there.

Before it collapsed, they actually did one better over the previous experiment and achieved self-sufficiency in food production. Colonists would need equipment shipped in until a manufacturing supply chain could be set up locally, but mostly Biosphere 2 serves as a cautionary tale of letting Steve Bannon and cults run things.

Even the claims of stir craziness were kind of overblown. They got evaluated, everything they experienced was consistent with everything that was known about long-term isolated group environments. They’re a rough experience.

It was a fine enough experiment in the early 90’s, but there are incorrect assumptions about how it would apply to space travel. For one, the Biosphere project is considered a “failure” because they set themselves the goal of creating a completely self-contained bubble that needed no outside inputs, and yet at various points systems in the sphere needed repair and replacement, which is completely normal and absolutely what would happen in space. No space company worth anything would let a mining colony collapse because a carbon scrubber broke and “hAhA yOu NeEd oUtSiDe InPutS tO kEeP lIviNG JuSt LiKe tErReStRiAl cOloNieS.” No, they’d ship in a new scrubber and keep the line moving.