The instrument will be carried by a superpressure balloon at a float altitude of 38 km. The superpressure balloon is designed by and will send data to NASA's Columbia Scientific Balloon Facility.

As the light travels through the box, a system of three Fresnel lenses will focus it on the photon detection module (PDM) and provide chromatic correction. Because the fluorescence spectra of EASs are in the ultraviolet, the PDM includes "a UV filter assembly that passes light between 290 nm and 430 nm." The PDM is 2304 pixels which each have a 0.25x0.25 FoV.

The gondola also includes a flotation device should the instrument land in water at the end of its flight.
EUSO-SPB will be calibrated using a set of calibration flashes from a 355 nm pulsed laser carried on an aircraft flown just below the balloon.