# Is graphite a better lubricant on the Moon than on the Earth? [closed]

My book says that it is a better lubricant on the Moon because of absence of gravitational pull on the Moon. However, I also read that it's lubricant nature is because of a film of moisture or gas molecules absorbed on the surface of its layers and in vacuum, it gets dried up and would be a bad lubricant. Which is correct?

• Googled enough to convince myself that "regular" graphite would be a bad lubricant in the vacuum of space, but couldn't find a good authoritative reference.
– MaxW
Oct 29 '18 at 17:56
• Gravitation pull has no impact on lubricity (contact forces perhaps). Oct 29 '18 at 18:33
• By curiosity: please state your source (here: your book) you cite. Perhaps SE Space Exploration has contributors who happens to know about the lubricants used for lunar rover and lunochod by NASA and pre-Roscosmos and their experiences. Oct 29 '18 at 22:36

Another solid lubricant, $$\ce{MoS2}$$, which has also a layered structure like graphite, works much better in vacuum and should be the lubricant of choice on the Moon.