Sentinels of the Heliosphere

What NASA calls its 'Heliophysics Observatory' is an impressive fleet of spacecraft designed (often with international partnership) to study the relationship between the Sun, Earth, and Solar System. Flying in an array of trajectories and orbits, many of these satellites do not take images in the conventional sense but record fields, particle energies and fluxes in situ to give mankind a better understanding of space weather and space environments.