Overview of multi-spacecraft observations of SEPs from January 2021 to January 2024. From top to bottom, we plot the hourly averages of (a) 4.3–7.8 MeV proton intensities measured by the EPHIN on board SOHO combined with 13–80 MeV proton intensities measured by the ERNE on board SOHO. (b) 8–64 MeV proton intensities measured by EPIHi on PSP. (c) 7.05–105 MeV proton intensities measured by HED on board Solar Orbiter. The radial distances of the PSP and Solar Orbiter spacecraft to the Sun are overplotted with orange lines and labeled in the right y-axes in panels (b) and (c), respectively. The magenta arrows in panel (a) indicate the 42 SEP events that were simultaneously observed by at least two of three observers (Earth, PSP, and Solar Orbiter).