A New Perspective in Adhesion Science and Technology: Testing Dynamic Failure of Adhesive Junctions for Space Applications

Under micro-gravity conditions, typical of the space environment, adhesion forces may play a relevant role in the manipulation of objects, especially when they must be released into free-fall under controlled residual velocity conditions. When only contact forces may be applied to the body that must be released to free-fall, no solution different from inertia is available to detach it from the manipulating device. If the manipulator is retracted from the body quickly enough, any adhesive bond existing between them is brought to failure, being loaded by the inertia force. The body acquires a residual momentum equal to the impulse developed by the adhesion force upon its failure. An experimental technique has been developed to characterize the impulse that adhesive junctions between two metallic rough surfaces develop upon dynamic failure, as part of the qualification of a system (the Caging Mechanism) designed for this specific function in the frame of the LISA Pathfinder space mission by the European Space Agency (ESA). This paper reports on the recent results obtained through the experimental campaigns performed in the LISA Pathfinder ground testing activities of the Caging Mechanism.