Spatial heterodyne spectrographs combine high spectral resolution with large étendue in a compact instrument. This combination makes them useful for studies of extended diffuse sources requiring velocity resolution or the separation of closely packed emission lines, while their small size makes them suitable for platforms ranging from ground-based observatories to satellites. Improvements in optical element and detector capabilities have expanded opportunities for SHS in the VUV, where its combination of size, resolution, and étendue have not been available. Here we discuss the basics of the SHS technique and how an instrument may be designed to study various emission line sources in the solar system.