A rocket payload able to perform a thorough and independent analysis of the He I 58.43340‐nm geocoronal and interplanetary emissions is presented. It includes a sun‐pointed resonant absorption spectrometer and a sky‐scanning resonant absorption photometer. Both incorporate a similar helium resonance cell of original design featuring a most flexible pressure scanning capability and an accurate pressure measuring device, so that scanning by wavelength bandpasses from 20 down to 1 pm can be achieved. A description of the design and calibration of the instrument is given, followed by an indication of its successful operation in flight.