The deep-space probe Ulysses has been on its mission to explore the Sun’s surface and the region close to the Sun, investigating the structure and variations of the heliosphere since 1990. The mission’s objective was to explore the regions to the south and north of the solar equator which are impossible to view from Earth. Its findings are vital to a better understanding of the Sun’s effects on the solar system. In addition, Ulysses is providing the first-ever map of the heliosphere from the equator to the poles.
The research space probe first flew in the direction of Jupiter in order to use its gravity to swing the spacecraft to the Sun’s polar regions. Ulysses became the first probe to cross the southern polar region of the Sun, and in 1995 it crossed the northern polar region. In 1998, Ulysses successfully completed the first orbit around the Sun. In 2001, the critical phase of the eleven year activity cycle, it reached the norther polar region once again. In early 2004, Ulysses had its second encounter with Jupiter, although not as close as in February 1992, which enabled it to re-enter solar polar orbit. The spacecraft made a third solar pole pass, which it started on 17 November 2006 at 80° ecliptic to the south pole.
Ulysses was built under the leadership of Astrium and jointly operated by ESA and NASA. The mission was extended to the end of 2008.
