Department of Atmospheric, Oceanic & Space Sciences in the College of Engineering at the University of Michigan

News

Spacecraft Ulysses' 18-year mission ends—AOSS involved from beginning

Posted: July 6, 2009

The joint NASA/European Space Agency (ESA) spacecraft Ulysses has sent its last transmission to Earth after 18 years orbiting the sun. The mission was originally scheduled to last just five years. Read the ESA press release. Read a story in Discover magazine.

Ulysses studied space weather and the solar wind, a stream of charged particles that fills the entire solar system. The information it provided helps scientists understand how the solar system interacts with intergalactic space. Read an ESA summary of Ulysses' legacy.

Many AOSS faculty members, researchers and students have been involved in this mission, including research professor George Gloeckler; Thomas M. Donahue Distinguished University Professor Lennard Fisk; professor Thomas Zurbuchen; and assistant research scientist Susan Lepri, all members of the U-M Solar and Heliospheric Research Group.

Gloeckler and others built the Solar Wind Ion Composition Spectrometer (SWICS), an instrument aboard Ulysses designed to determine the elemental and ionic-charge composition, temperatures and mean speeds of all major solar-wind ions.

"Ulysses has transformed our understanding of space," Zurbuchen said. "Its polar vantage point has provided unique and breakthrough insights into our understanding of the solar wind and its source, the solar atmosphere."

The craft measured the cosmic interacion of the solar system with the Milky Way galaxy. It measured the inflowing gases and stellar dusts, as well as the high-energy radiation that is formed in this interaction. Most of these measurements were true firsts, Zurbuchen says.

"Never before and not again in the near future will we have such a unique opportunity to view the three-dimensional nature of the heliosphere," Lepri said. "Ulysses played a monumental role in helping us understand the global nature of solar phenomena and the Sun's impact on our world."