Micropatterned Dry Adhesives (MDA), commonly referred to as geckomaterials, mark a significant advancement in the field of
space robotics for CubeSats. These materials offer an innovative, lightweight, and passive approach for capturing and docking to various objects in space. Potential mission objectives therefore include active space debris removal, on-orbit servicing, and in-space manufacturing. Their ability to adhere to almost any surface via van der Waals forces, independent of the surrounding atmosphere, makes them particularly suitable for vacuum conditions in space. Predominantly fabricated from elastomers such as silicones and polyurethanes, these adhesives are prized for their resilience to extreme temperature cycles and their tolerance to substantial doses of alpha and gamma radiation, as reported in several studies. However, the effects of other space environmental factors, such as different forms of radiation, UV exposure, atomic oxygen, and especially their cumulative impacts on these materials remain largely unexplored.
To address this knowledge gap, a comprehensive study was conducted at the ESA ESTEC Materials and Electrical Components Laboratory as part of the Materials4CubeSats Testing Campaign. The research focused on four types of MDA: two made of polydimethylsiloxane (PDMS) featuring mushroom-shaped pillar microstructures with base diameters of 400 μm and 50 μm respectively, and two composed of polyurethane (PU) with identical microstructures. Each sample underwent one of six specific testing routes to assess their longevity and adaptability in space-like conditions. These routes included outgassing screening; vacuum thermal cycling; UV radiation exposure; atomic oxygen exposure; combined vacuum thermal cycling, UV radiation, & atomic oxygen exposure; as well as UV radiation & atomic oxygen exposure. This paper presents the detailed results from these tests, providing critical insights into the durability and adaptability of synthetic dry adhesives under various space environment conditions.