A NASA satellite launched in 1994 November to study the incoming solar wind and the Earth’s magnetosphere. Initially it was placed in a series of highly elliptical orbits with apogees from 80 to 250 Earth radii over the Earth’s day side, then in 1997 moved to a halo orbit around the L1 Lagrangian point between the Sun and Earth. In 1998, it returned to a series of orbits around the Earth, this time at inclinations up to about 60°, allowing it to study conditions far from the ecliptic. In 2004 it was returned to the L1 point permanently.
http://www-istp.gsfc.nasa.gov/wind.shtml Official mission website.
http://wind.nasa.gov/ Mission page at NASA.