Ulysses was a joint NASA/ESA (European Space Agency) probe to study the Sun, the interplanetary medium and the makeup of the solar wind. Ulysses provided the first opportunity for measurements to be made over the Sun's poles. Originally named the International Solar Polar Mission, the spacecraft used a gravity-assist from Jupiter to leave the ecliptic plane. It completed passes over the Sun's southern pole in November 1994 and northern pole in October 1995, at which point its primary mission was completed. It then began an extended phase of observations, which lasted until 2008.