Originally Posted by lightspree

Speaking of SR-71s, NASA has some things to say, based on their experiences with lubricants,

General lubrication problems and lessons learned with spacecraft deployable appendages include: [Devine]
...

Maximum utilization of rolling surfaces as opposed to sliding motion should be employed.
Lubrication or separation of all moving surfaces either by suitable aerospace grease or dry lubricant coating should be used. No exceptions are allowed, even for lightly loaded friction-compatible surfaces.
...

Wet lubrication is generally preferred because friction is low and predictable. The grease with the most heritage is the Braycote 600 series, a synthetic-fluorinated oil-thickened grease with micron-size Teflon powder. The grease has extremely low outgassing (TML <0.1% and CVCM <0.05% for the standard 125 C 24-hr test) and concerns relative to contamination are negligible for virtually all spacecraft applications. The wet lubricant usable temperature range is -80 to 200 C.
...

It was demonstrated, on a test of a spacecraft oscillating scanner that the polyalpholefin (PAO) oil provided excellent lubrication, consistent torque with negligible torque noise, and good wear to 22,000 hr with the test still running. The other oils (chloroaryalkylsiloxane (CAS), originally used in the application, and a perfluoropolyalkylether (PFPE)) exhibited a reduction in torque (loss of preload) and an increase in torque noise, as well as extensive wear after a few thousand hours. [Feherenbacher]

So it appears that some lubricants may extend component life much better than others.

Space Mechanisms Project

http://www.aerosuppliesinc.com/Catal...0(505-595).pdf