In-Space Vat Photopolymerisation: Containment, Optics, Heat, Motion and Part Release in Microgravity

In-space vat photopolymerisation is not terrestrial VPP placed in a spacecraft. Reduced gravity suppresses buoyancy-driven flow, pressure reduction expands trapped gases and promotes volatile loss, heat rejection changes, free surfaces become capillary-dominated and part release cannot rely on weight. Recent photopolymer manufacturing experiments under microgravity and reduced pressure provide direct evidence for several of these effects. This review converts that evidence into a qualification framework for containment, resin preparation, optics, thermal control, motion, interfaces and part release, while separating true VPP requirements from adjacent extrusion demonstrations.