The composition and structure of neutral exospheres imbedded in the solar wind can be determined by measurements of their pickup ion progeny. Using Earth's Moon as the parent body, we consider transport of pickup ions from their birthplaces to measurement sites on possible spacecraft orbits. An ion observed to have a specific mass and velocity at a spacecraft position can be mapped back to its point of birth on the surface or in the atmosphere. Ion measurements of this type are shown to be a sensitive way to map the composition of surfaces and atmospheres of bodies with surface bound exospheres.