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Guidelines For Introduction of New Oils and Greases into Mechanism Qualification Programs – Now Released By ESTL

28th February 2024

Until now, no guidance has been available for those seeking to employ a new oil or grease product in a space mechanism intended for flight qualification. However, a guideline document (ESA-ESTL-TM-0375 01- “Guidelines for Qualification of New Fluid Lubricants”) recently released by ESTL and available in ESTL’s Members’ Area aims to provide clarity concerning the lubricant verification and validation prerequisites ultimately to be required by the European Space Agency (ESA) in this situation.

But the space industry already has mature oil and grease products, with ample heritage that perform very well in many space applications. What is the problem – is there a need to introduce anything new?

Indeed, only a few months ago, this topic may have seemed prosaic; however, the implications of possible environmental legislation under discussion in Europe, the USA and elsewhere render the introduction of new oils and greases a topic of increasing interest to many space mechanism engineers.

Concerns that the environmental persistence of PFAs on Earth may prohibit the use of PFPEs, PTFE as a thickener or in bulk and perfluorinated solvents used in space have led to the need for guidance concerning how to introduce new lubricants for several reasons.

  1. In some cases, grease price and availability have become incentives to switch to new products.
  2. New lubricant chemistries, additives and process routes are under development to meet the challenge of future missions and in some cases offered by new providers.
  3. Finally, environmental legislation proposals may be diluted, postponed, or shelved – but as an industry, isn’t it simply prudent to prepare for its eventual implementation?

ESTL’s guideline document (also previewed in a paper at the 2023 ESMATS ( ) aims to clarify ESA’s position on the lubricant verification and validation needed for “new-to-space” oil or grease lubricants or new variants of a pre-existing fluid lubricant before they can be considered for inclusion in a mechanism qualification program.

Our document is being released at Issue 1 for industry comment.  Following feedback and practical implementation of two lubricants being done by ESTL in 2024, it will become mandatory to adopt the approach outlined in the guideline when introducing any new lubricant.

If you have access to ESTL Members’ area, please take a look at this important new guidance document and provide your feedback. Any feedback can be sent to Anthony Kent via email at, and it will be appreciated.