National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
News & Events
Plasma Spectrometer Operations on Hold
Plasma Spectrometer Operations on Hold
15 Jun 2011
(Source: NASA/JPL)

Cassini at Saturn
Artist concept of Cassini at Saturn. Image credit: NASA/JPL

PASADENA, Calif. - Mission managers for NASA's Cassini spacecraft suspended operation of the Cassini plasma spectrometer instrument on Tuesday, June 14, 2011, after a series of voltage shifts on the spacecraft. They will determine when the instrument can resume collecting data.

The Cassini spacecraft is designed to operate with a "balanced" voltage source to create a tolerance to short circuits. On May 1, a voltage shift occurred, most likely explained by a short circuit happening somewhere in the system. On June 11, a voltage shift in the opposite direction occurred, indicating an additional short circuit. In both cases, all instruments and engineering subsystems continued to operate properly.

Analysis of telemetry data from the spacecraft by the engineering team pointed to the Cassini plasma spectrometer instrument as the cause of the voltage shifts. The instrument has additional capacitors in the power lines for noise reduction. The concern was that one or more of these capacitors may have short-circuited, which would cause the voltage to shift and explain the observed changes. Although the instrument was operating properly, engineers decided to turn it off as a precaution until the events could be better understood.

The suspension of the plasma spectrometer operations is not expected to affect other science data gathering or navigation. The plan is to resume normal plasma spectrometer operations after further analysis is completed to understand the cause of the issue better.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington.

More Cassini information is available at and

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.


News Archive Search  Go!
Show  results per page
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writers: Courtney O'Connor and Bill Dunford
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> NASA Advisory Council
> Open Government at NASA
Last Updated: 15 Jun 2011