The first international mission to the Sun

  • In operation
  • Launched 6 October 1990
  • Due to end in 2008
The primary mission of Ulysses is to examine the heliosphere – the vast region of space occupied by the Sun’s atmosphere. The heliosphere is dominated by the stream of charged particles coming from the Sun known as the solar wind.

Ulysses is a joint mission between NASA and the European Space Agency (ESA) with key involvement from UK science teams.

The data sent back by Ulysses is helping scientists understand how the Sun works and what affect it has on the rest of our Solar System. Understanding solar activity has important consequences for Earth and its inhabitants. The solar wind can cause magnetic storms and affect our weather and satellites. It can even disrupt power supplies and communication systems on Earth.

Many of the scientists working on Ulysses, or using results from the mission, are also involved in SOHO, STEREO and Hinode.

Mission facts

  • Ulysses is named after the hero of Homer's epic tale The Odyssey. In the legend, Ulysses took ten years to find his way home after the Trojan War. Like its namesake, the spacecraft has ventured into previously unexplored territories.

  • The Ulysses spacecraft orbits the poles of the Sun in a long ellipse. It takes six years for Ulysses to complete a full circuit of the star.


Ulysses carries 15 different scientific instruments. Measurements are taken of cosmic, gamma and X-rays as well as electrons and cosmic dust. Results from these instruments are helping scientists study every aspect of the Sun and its surroundings.

UK involvement

Imperial College London and the University of Kent helped to build four of the instruments on board. The team at Imperial lead the studies of the Sun's magnetic field.

For more information, visit the ESA web pages and the NASA web pages.

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