30 years of observing the Sun’s magnetic field from space

2026 is a double anniversary for observations of the Sun’s magnetic field from space. Thirty years ago, the Michelson Doppler Imager (MDI) on the Solar & Heliospheric Observatory (SoHO) began the first continuous full-disk observations from L1. Twenty years ago, MDI was joined by the Solar Optical Telescope (SOT) on the Hinode mission at LEO commenced gathering the highest resolution and cadence vector magnetograms uncontaminated by atmospheric seeing. They have been followed by the Heliospheric and Magnetic Imager (HMI) on the Solar Dynamics Observatory (2010) and the Polarimetric and Helioseismic Imager on Solar Orbiter (2020) at GEO and heliocentric orbit respectively. Here we review the history and scientific results from these trailblazers and extrapolate how future instruments and missions will support exploration throughout the heliosphere.