Space effects on materials

AAC has established a wide expertise: on one hand expertise in materials characterisation, and on the other hand several very specific test devices that are necessary to validate (new) materials and processes for use in space.

Through its role as consultant and testing provider in ESA-projects on a wide range of applications, AAC has also gained expertise in developing Requirement Specification Documents (RSD). This enabled a survey of effects that are imposed to materials when operating in space. Moreover, also after having finished operative life materials may contaminate the space craft if being degraded.

Some examples for such effects are:

• Outgassing
• Contraction of fibre reinforced polymers (CFRP) due to water loss, see “CME”
• Stress Corrosion cracking (SCC): long term life on ground under tensile stresses may initiate micro-cracks, that cause failure when getting launched.
• Cold welding: welding of two metallic materials in contact when being vibrated in vacuum, causes forming of weld even at ambient temperatures, that may hinder deployment in orbit.
• Radiation: may degrade all materials, from thermal protection foils (TPS), OSRs, structural polymers, but also materials being inside the space craft like cages of bearings. Degradation of materials is characterised e.g. by loss of mechanical or tribological performance.
• ATOX: atomic oxygen is present in low earth orbits and is strongly degrading polymers.
• Whisker growth: selected metals grow very tiny hairs (few microns in diameter but up to mm long), so-called whiskers, especially for new solders this effect is known. Such whiskers may endanger electronic boards, as they may cause short cuts.

AAC is running several tests and characterisations on materials and components in-house, but offers to act as “one-stop-shop” for complete test campaigns. AAC assists also in setting up the RSDs, that combines the requirements for a material towards a specific application and the required verification campaign.