Foam Spray Analysis Software for Space Shuttle

Polyurethane foam is applied to the Space Shuttle External Tank with both automated and manual spray equipment. The areas requiring manual closeout typically have intermittent obstructions located between the spray gun and the primary surface to be coated. Dissections of cured foam areas have shown occasional voids in the foam adjacent to obstructions. Other area of concern is the Longeron closeout area that provides an attachment location for the thrust struts to the External Tank. The closeout inspections revealed potential foam elimination from the sidewalls.

Simulent Consulting Inc. was asked to develop simulation software to predict the whole spray foaming process. The software comprised of several modules that predicted the microstructure of the resultant foam as a function of spray gun design, gun movement and surface typology.