The Discovery One rotates to create artificial gravity, and Kubrick shows us this working perfectly: the crew walks normally, food sits on tables, water stays in cups.

Problem solved—except rotation doesn't solve the problem it creates.

Every crew member lives in a physical space where authority is literally unstable. The captain's quarters are "up," the engine room is "down," and someone standing in the hub experiences neither, which means someone standing in the hub experiences freedom from the social order that keeps the rest of the ship functioning.

Watch the scene where Frank Poole does his repair walk outside the ship. He tethers himself because he understands one thing clearly: without artificial gravity, you're weightless. But inside the ship, he's not weightless—he's in a rotating frame where his sense of "down" depends entirely on where his body is positioned.

The mission works in the film because no one questions authority, but the Discovery fails in any mission where they do.