Both chambers hold the same protein solution around a tiny nucleated seed. Growing a good crystal means letting individual protein molecules dock onto the lattice one at a time, in order — the slower and calmer that process, the more perfect the result.
On Earth, warm, less-dense solution near the growing crystal rises while cooler solution sinks, driving a constant buoyancy convection current. That current sweeps fresh molecules in unevenly and irregularly, occasionally slamming the growth front hard enough to trap impurities and stall whole faces — a rough, smaller, defect-riddled crystal. In orbit, there is no "up" for buoyancy to act on: molecules reach the crystal by diffusion alone, drifting in undisturbed at a steady rate, so the lattice can grow layer by layer into a larger, cleaner, more geometrically ordered shape.
Earth: flux(t) = diffusion + Σ sin(ωᵢt+φᵢ)·Aᵢ (convection dominates)
Orbit: flux(t) ≈ diffusion only (no buoyancy term)
defect chance ∝ |local flux disturbance| at the moment a molecule docks
- Earth / Microgravity — swings the camera to inspect either chamber and highlights its stats.
- Start growth — runs both chambers' clocks together from the same solution, so the comparison is fair.
- Time-lapse speed — compresses the (real) days-to-weeks growth process into a watchable simulation.
- Watch the Earth crystal pick up red defect specks and stop growing early as convection currents keep disturbing it, while the orbital crystal grows on, smooth and gold, largely unblemished.
Real-world relevance: this is the actual rationale behind flying protein-crystallization experiments to the ISS — larger, more ordered crystals diffract X-rays more sharply, which is often the deciding factor in resolving a protein's atomic structure for structure-based drug design.