Galileo Continues to Transmit Images and Data to Earth

Three weeks from its next close flyby of Jupiter's volcanic moon Io, the Galileo spacecraft continues to process and transmit to Earth images and science data stored on its onboard tape recorder. The data were acquired during Galileo's previous flyby of Io on October 10 (Pacific Time). Data taken by the Near-Infrared Mapping Spectrometer (NIMS) and Solid-State Imaging camera (SSI) during that flyby are returned this week. Data playback is interrupted twice this week. Having performed a relatively large flight path adjustment last week, the spacecraft will fine tune its flight path on Wednesday, if necessary. On Thursday, the spacecraft performs standard maintenance on its propulsion systems.

This week Galileo continues playing back observations from a third pass through the data stored on board. Additional passes through the tape recorder allow replay of data lost in transmission to Earth, reprocessing of data using different parameters, and/or return of additional new data. SSI continues to return images that are likely to be corrupted. They are being returned with the expectation that careful processing will allow important scientific information to be gleaned from some of these images.

First on the playback schedule is the return of SSI and NIMS observations of Dorian Mons. Dorian Mons is a mountainous feature whose geological structure, origin and history are presently unknown. Furthermore, Dorian Mons is distinct from other similar features in that it shows greenish colored deposits. Next, SSI and NIMS return moderate resolution images and spectrometer scans of the Amirani, Skythia, and Gish Bar regions. In the final dual observation returned this week, SSI and NIMS return data from a region of Io's surface near the moon's terminator (the imaginary line between day and night). The oblique lighting conditions of the observation are optimal for studying the topography of this region, a region containing the Hi'iaka caldera.

NIMS continues on the playback schedule with the return of a regional observation of Io. The observation was designed to study surface composition and detect thermal emissions. SSI returns the last observation of this week. It is a regional mosaic of Io that contains images which will be combined with data obtained in July to produce stereo views of the region