Molecular clouds are a crucial stage in the lifecycle of a star, and the far ultraviolet (FUV) spectral range is a prime observation band. Hyperion is an FUV space telescope that investigates the birth clouds of stars using a high-resolution spectrometer. To meet the scientific requirements, we developed and evaluated a spectrometer that covers the 140.5 to 164.5 nm wavelength range with a spectral resolution higher than 30,000. We employed on-axis and on-plane dispersive optic layouts to control the aberration from a large aspect ratio slit (10  arcmin  ×  2.5  arcsec, aspect ratio R  =  240). The cross-dispersion isolates three orders from the échelle grating (n  =    −  19, −18, and −17), and the subsequent two-mirror freeform imaging optics form a two-dimensional spectral distribution on a 50  mm  ×  50  mm detector array. The geometrical and spectral performances of this innovative design are evaluated.