Investigation of long-term storage of space materials for future constellation missions: study of Braycote^® 601 EF lubricant

Abstract

The long-term storage (LTS) of space materials is becoming more and more critical for the next missions. For instance, for MTG (Meteosat Third Generation) mission, 5-year assemble, integration and testing (AIT) time on ground, up to 17.5-year storage for recurring models plus at least 8.5 years in orbit operation are planned. Hence, a good understanding of materials’ aging properties is desirable to ensure that materials’ specifications are still suitable after LTS, and, eventually, to anticipate the potential non-conformities. For this purpose, the European Space Research and Technology Centre (ESTEC) is investigating these problematics thanks to its wide capabilities from aging with environmental, climatic and vacuum chambers up to physico-chemical characterizations by numerous instruments such as microscopes, spectroscopes, thermal, mechanical or electrical analyzers. An overview is presented herein through the study of a fluorinated based grease lubricant named Braycote® 601EF widely used in mechanisms in space sector such as the US space shuttles actuator or the basic end effectors of The European Robotic Arm.

Development of a Space Grease Lubricant with Long-Term-Storage Properties

“…Real-time data for LTS are hardly available, and predictions based upon accelerated models typically lack verification. The retainment of tribological properties of the PFPE-based grease Braycote 601 EF (Castrol) after 17 years of storage was presented in a NASA study, and the findings were confirmed in a recent publication [23,24].…”