First of all, Hi ;-) So I am familiar with friction and how to make estimates for it, but how about friction in vacuum? Some thoughts of mine: * lack of moisture, so no film * increased adhesion (maybe due to the above) An extra complexity by adding heat (up to 400 degrees C) * what happens to stainless steel grades in this environment? When in contact, sliding or rolling? Any thoughts are welcome, as new views or expertise might help me solve and avoid some problems. Thanks in advance!