The absence of gravity-driven convection eliminates the negative effects of density gradients (inhomogeneous mass distribution) that arise in processes involving heat treatment, phase transitions, diffusive transport or chemical reaction.
Convection in terrestrial processes is a strong perturbing factor, the effects of which are seldom predictable with great accuracy and which dominate heat and mass transfer in fluids.
The ability to accurately control such processes remains limited, and their full understanding requires further fundamental research by conducting well-defined model experiments for developing and testing related theories under microgravity.
The Optical Diagnostics Module houses the equipment for visual and interferometric observation, their related control electronics and the attachment points and interfaces for Front Mounted Cameras.
Most notable among these are a new Video Management Unit (VMU) and the Microgravity Vibration Isolation Subsystem (MVIS) developed by the Canadian Space Agency.