A solar-terrestrial mission by NASA’s Goddard Space Flight Center as part of the Global Geospace Science and International Solar-Terrestrial Physics programmes to provide complete plasma, energetic particle, and magnetic field data for studies of the magnetosphere and ionosphere, determine the magnetospheric output to interplanetary space in the upstream region, investigate basic plasma processes in the near-Earth solar wind, and provide observations for missions to the inner and outer heliosphere. The satellite was launched on 1 November 1994, from Cape Canaveral, initially into a double-lunar swingby orbit near the ecliptic plane, apogee 80–250 R_E, perigee 5–10 R_E. In 1996 the mission was extended, and WIND was inserted into a halo orbit about Lagrangian point L1, at 235–265 R_E.