Ulysses - A journey above the sun's poles

Neither the heating of the solar corona nor its acceleration to form the solar wind are well understood; the Ulysses spacecraft launched on October 6, 1990, will address these questions through observations of the polar regions. These observations will give special attention to the presence and properties of waves that have proposed either to heat the corona, to help accelerate the solar wind, or to heat the wind after it escapes from the sun. Another major objective of Ulysses is to map the solar magnetic field in the polar caps.