Abstract In the frame of a collaboration between CERN, ASI, University of Trento, and TIFPA, the HTS demonstrator magnet for space project has started to define methods and procedures for manufacturing high temperature superconducting magnets for space applications. To this purpose, we developed a conceptual design of a superconducting magnetic spectrometer for a physics experiment in space. The configuration is a toroid with twelve superconducting coils based on ReBCO tape. By using ReBCO tape with an engineering critical current density, J e , exceeding 1000 A mm −2 at 4.2 K and 20 T , as reached in the H2020-ARIES program, the magnet system provides an average bending strength of 3 T m . This is sufficient to measure charged particles with rigidities up to 100 TV , more than two orders of magnitude higher than the present state-of-the-art space spectrometer. The magnet system requires about 62 km of 12 mm ReBCO tape and produces a peak magnetic field of 11.9 T at an operating temperature of 20 K . A small scale single coil, which is about one third in size of a coil from the toroidal magnet system, will be manufactured and tested as demonstrator of the magnet technology. The mechanical structure and performance of the toroidal magnet system and demonstrator coil are described.