Gathering data from Cassini space mission, Hubble Space Telescope

December 15, 2000

Gathering data from Cassini space mission, Hubble Space Telescope

ANN ARBOR—After years of waiting, a team of researchers at the University of Michigan College of Engineering will receive an early Christmas present this week—an up-close look at the mysterious aurora surrounding Jupiter and a chance to gather valuable data about how the aurora behaves.

As Cassini reaches its closest point to Jupiter—approximately 10 million kilometers, compared with a distance of 600 million kilometers from Earth—researchers have a rare opportunity to simultaneously gather data and images about the aurora from Cassini and the Hubble Space Telescope.

For researchers at U-M, it’s a once-in-a-lifetime opportunity to conduct a real-time experiment from 600 million miles away. The test will involve using instruments aboard Cassini to take direct measurements of the solar wind and determine the amount of pressure those winds exert on Jupiter. Since the solar wind changes as it flows away from the sun, this must be done close to Jupiter, and the Cassini trajectory provides a unique opportunity to do this.

Meanwhile, the Hubble Space Telescope will capture detailed images of the brilliant bands of colored light that are generated by the aurora. (Images are available online at

The goal is to analyze the relationship between the solar wind measurements and the images to determine how solar winds influence the aurora around Jupiter. That information, in turn, may help researchers understand some of the differences between Jupiter and our planet.

“The aurora around Jupiter is vastly different than what we experience on Earth. It’s almost 1,000 times more energetic and appears to be much more complex. We know that the solar wind controls the Earth’s aurora, but we’re not sure how it influences Jupiter,” said John Clarke, research scientist in the College of Engineering’s Department of Atmospheric, Oceanic and Space Sciences and a principal investigator for observations from the Hubble Space Telescope. “This project will double the amount of existing high-resolution data that Hubble has collected on Jupiter’s aurora.”

The two spacecraft collect data over a two-week period beginning Dec. 14. U-M researchers will then begin closely examining the images along with a host of statistics about the solar wind, including velocity, temperature, pressure, density, and magnetic field direction.

A second campaign in
In addition to the job at hand, this experiment also serves as an important “test run” for the Cassini spacecraft, launched by space organizations in the United States and Europe in 1997. It will be the first significant opportunity to exercise the spacecraft’s operational abilities as it travels to Saturn (arrival date: 2004).

Expert Resources Available at the U-M College of Engineering

Jupiter may be 600 million miles away, but the epicenter of planetary research will be located in a single hallway in Ann Arbor, Mich., for the next two weeks. That’s where three researchers from the U-M College of Engineering will be working to analyze the data gathered by Cassini and the Hubble Space Telescope.

The following experts are available to discuss this ground-breaking research project:

John ClarkeResearch Scientist, Department of Atmospheric, Oceanic and Space SciencesUniversity of Michigan College of Engineering

Clarke is the principal investigator for observations using the Hubble Space Telescope and is responsible for collecting images of the aurora. He has been involved with the Hubble Space Telescope project since 1984, when he began work with NASA as a deputy project scientist for the Hubble program. After three years of involvement with Hubble instrumentation, he joined the U-M faculty in 1987.

David YoungProfessor, Department of Atmospheric, Oceanic and Space SciencesUniversity of Michigan College of Engineering

Young is the principal investigator for the Cassini Plasma Spectrometer, an instrument that measures the density, speed, and temperature of the solar wind as it flows past Jupiter. He first became involved with Cassini in 1988 and subsequently formed a team of over 100 scientists and engineers from six countries who designed, built, and calibrated the Cassini Plasma Spectrometer. Young joined the U-M faculty in 1999.

J. Hunter WaiteProfessor, Department of Atmospheric, Oceanic, and Space Sciences University of Michigan College of Engineering

Waite is the facility team leader of the Ion Neutral Mass Spectrometer on the Cassini/ Huygens mission. He is a co-investigator for the Hubble Space Telescope observations and for supporting Chandra X-ray observations during the Cassini fly-by period. He has been a key organizer of the coordination, providing communications between the Cassini and Hubble observation teams. Hunter has just joined U-M’s Department of Atmospheric, Oceani, and Space Sciences after 12 years at the Southwest Research Institute in San Antonio, Texas

Tamas GombosiProfessor, Departments of Atmospheric, Oceanic and Space Sciences, Aerospace EngineeringUniversity of Michigan College of Engineering

Gombosi is an interdisciplinary scientist within the Cassini program, responsible for studies of magnetospheric processes. He is a well-known expert in applying computational fluid dynamics to space environments. As a member of the Cassini-Hubble Space Telescope fly-by collaboration, he is responsible for developing computer models to demonstrate and predict the solar wind interaction with Jupiter’s magnetic field.

College of ClarkeDavid YoungTamas Gombosi