Solid lubricants are used in high-consequence aerospace applications to insure predictable friction and wear behavior over a wide range of temperatures. These materials are frequently stored for months before they are placed in service, and may be dormant for years prior to operation. Our research team has recently developed a model of interlamellar shear in MoS₂ that is based on the energy barriers to lattice reorientation at the sliding interface. This model explains the temperature-dependent friction behavior of pure MoS₂ in inert atmospheres, with no adjustable parameters. In practical atmospheres, however, MoS₂-based solid lubricants may oxidize or adsorb reactive species from the environment, resulting in elevated friction coefficient during initial sliding. The focus of our research is the understanding of atomistic phenomena occurring during shear of solid lubricants, and the use of this information to develop more environmentally-robust and age-resistant solid lubricants. [Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.]