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.

After whirling around the sun since its launch in 1990, Ulysses has accomplished its mission. It has provided earthlings data on interstellar dust particles and interstellar helium atoms in the solar system.