Today on Galileo

August 13, 1999

Galileo Embarks on Third Day of Encounter

Today Galileo embarks on the third of four days of encounter operations. Jupiter and Io are the main targets of today's observations, which are performed primarily by the Solid-State Imaging camera and Utraviolet Spectrometer. In addition to the observations with the Jovian system, the camera also obtains some data to calibrate one of its filters by looking at Saturn and its moon Titan!

Today's activity is dominated by an extensive series of observations (or campaign) performed by the Solid State Imaging camera and the Ultraviolet Spectrometer. This campaign looks at nine different locations on Jupiter and obtains measurements of five different types of features of Jupiter's atmosphere. These data are designed to enable scientists to study the dynamics of cloud motion in Jupiter's atmosphere. The two instruments account for a total of 43 observations, 34 by the Solid-State Imaging camera and 9 by the Ultraviolet Spectrometer. The features observed in this campaign are a hot spot, a region know for the appearance of lightening, a region in Jupiter's north equatorial belt, a region at high northern latitudes, and a region near Jupiter's north pole.

In addition to observations of particular regions in the Jovian atmosphere, the Ultraviolet Spectrometer performs two other types of observations. In the first type of observation, the Spectrometer obtains measurements that will help to determine how minor components of the atmosphere are involved in the dynamics of the upper atmosphere. In the second type of observation, the Spectrometer looks at auroral activity near Jupiter's south pole. The observation is designed to provide scientists with a view into the interaction of Jupiter's upper atmosphere with Jupiter's magnetosphere.

Six observations related to Io are performed today, five by the Solid-State Imaging camera and one by the Ultraviolet Spectrometer. The camera observations are the second half of a ten-observation campaign designed to monitor volcanic plume activity on Io. Attempts will be made to compare the volcanic activity seen in these images to measurements of the Io torus taken by the Fields and Particles instruments. The Ultraviolet Spectrometer observation does not look at Io directly, but rather makes measurements of the Io torus. The torus is a region of relatively dense plasma (which originates at Io) and is characterized by intense radiation activity and strong magnetic and electric fields. The plasma is believed to be constantly replenished by the volcanic activity on Io. This observation will allow scientists to keep track of signficant changes in the characteristics of the torus.

For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page.

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Last updated: August 13, 1999

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