The mission to study the Sun's heliosphere is coming to a close after 17 years.

"The main objective of Ulysses was to study, from every angle, the heliosphere, which is the vast bubble in space carved out by the solar wind," said Ed Smith, Ulysses project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Over its long life, Ulysses redefined our knowledge of the heliosphere and went on to answer questions about our solar neighborhood we did not know to ask."