Might absence of dust on moon (such as for astronauts' experience) relate to importance of material sciences? That is, might surfaces interact electronically, seeking a more stable lowest energy configuration? Imaging it as if 2 grates rubbing together, seeking best fit? Air might then disrupt such surface interaction, such as for Martian dust. Hence then the ancillary idea of moving surfaces slightly intermittently, so as to disrupt such 'settling in', for joints of machines, such as Canadian arm on shuttle, and for space probes such as Huygens-Cassini.