A Quarter Century of WindSpacecraft Discoveries

The Windspacecraft, launched on November 1, 1994, is a critical element in NASA’s Heliophysics System Observatory (HSO)—a fleet of spacecraft created to understand the dynamics of the Sun‐Earth system. The combination of its longevity (>25 years in service), its diverse complement of instrumentation, and high resolution and accurate measurements has led to it becoming the “standard candle” of solar wind measurements. Windhas over 55 selectable public data products with over ∼1,100 total data variables (including OMNI data products) on SPDF/CDAWeb alone. These data have led to paradigm shifting results in studies of statistical solar wind trends, magnetic reconnection, large‐scale solar wind structures, kinetic physics, electromagnetic turbulence, the Van Allen radiation belts, coronal mass ejection topology, interplanetary and interstellar dust, the lunar wake, solar radio bursts, solar energetic particles, and extreme astrophysical phenomena such as gamma‐ray bursts. This review introduces the mission and instrument suites then discusses examples of the contributions by Windto these scientific topics that emphasize its importance to both the fields of heliophysics and astrophysics. The Windspacecraft is a south ecliptic pointed spinning spacecraft that was launched on November 1, 1994. It is equipped with an array of instrument suites that measure electric and magnetic fields, electrons from thermal to relativistic energies, protons and alpha‐particles from thermal to suprathermal energies, and energetic ions from hydrogen to trans‐iron elements. Windcan also observe remote sources of electromagnetic radiation in the radio and gamma‐ray frequency ranges. This diverse array of instrumentation and numerous near‐Earth environments explored has allowed researchers to examine such a broad range of research topics including astrophysics, turbulence, kinetic physics, magnetic reconnection, interplanetary and interstellar dust, transient solar phenomena, and the radiation belts. Examples of the contributions of Windto the fields of heliophysics and astrophysics are reviewed. Windhas made seminal advances to the fields of astrophysics, turbulence, kinetic physics, magnetic reconnection, and the radiation beltsWindpioneered the study of the source and evolution of solar radio emissions below 15 MHzWindrevolutionized our understanding of coronal mass ejections, their internal magnetic structure, and evolution Windhas made seminal advances to the fields of astrophysics, turbulence, kinetic physics, magnetic reconnection, and the radiation belts Windpioneered the study of the source and evolution of solar radio emissions below 15 MHz Windrevolutionized our understanding of coronal mass ejections, their internal magnetic structure, and evolution