The development of appropriate space-lubricants requires careful consideration to ensure the reliability and longevity of spacecraft components. Given the difficulty and expense of maintenance or replacement, long lifetimes and consistent performance over extended periods are needed to ensure the reliability of mechanisms. Space lubricants require tight specifications to meet the application-based requirements, and only specific compounds can come into consideration.

Recently, the long-term-storage (LTS) properties of lubricants have gained an increasing focus due to extended storage periods of lubricated components over multiple years in preparation of space missions. Real-time data for LTS is hardly available, and predictions based upon accelerated models typically lack verification. Strategies and methods to assess LTS properties of lubricants need to be elaborated, requirements to be defined and transferred into material parameters. In particular the oil physical separation of greases is yet poorly understood. The development ofThe The a new perfluoropolyether-based (PFPE) space lubricant with improved tribological lifetime that has been tailored towards LTS properties shall be presented.

Space lubricants consist of base oils like perfluoropolyether (PFPE) or multiple alkylated cyclopentanes (MAC) that are manufactured on the basis of fossil raw materials. This is also the case for polytetrafluoroethylene (PTFE, “Teflon”), the most common thickener for the manufacturing of lubricant greases for space. Also, a current proposal by the European Chemicals Agency (ECHA) might widely restrict the use of per- and polyfluorinated substances (PFAS), to which PFPE and PTFE belong to. The potential impact of a PFAS regulation and the increasing tendency towards the replacement of fossil-based products requires the identification and development of alternative lubricant options. Results from ongoing investigations related to the development of innovative PFAS-free lubricants will be shown.