While traversing its orbit, Ulysses encountered the tails of three distinct comets: McNaught, McNaught-Hartley, and Hyakutake. Although Ulysses was hundreds of millions of miles away, scientists got unexpected readings.

Ulysses, joint-venture between European Space Agency and NASA will send its final communication on June 30, 2009. Its primary mission was to characterize the Sun and its influence on the space environment.