Mass Flow
Mass flow measurement quantifying the amount of gas released from a surface area per unit of time. Outgassing rate density identifies how quickly volatile compounds escape from polymers, adhesives or metals in a vacuum environment. It determines the cleanliness and longevity of sensitive optical and electronic instruments.
Laboratory Testing
Laboratory testing measures the loss of mass at specific temperatures. The outgassing rate density is calculated by dividing the total mass loss by the exposed surface area and the duration of the test. Results are typically expressed in grams per square centimeter per second.
Environmental Influence
Thermal energy drives the diffusion of molecules toward the material surface. An increase in operating temperature notably raises the outgassing rate density, which can lead to the contamination of nearby sensors. High vacuum levels also accelerate the process by removing the gas molecules that would otherwise impede the release of further volatiles.
Technical Impact
Contaminants redeposit on cool surfaces as thin films that scatter light or degrade electrical insulation. Low outgassing rate density is a requirement for materials used in space applications to prevent the clouding of camera lenses or the short-circuiting of high-voltage components. Material selection relies on total mass loss and collected volatile condensable material percentages to ensure long-term mission success.
