This Week on Galileo - May 19-25, 1997
This week Galileo continues with the playback of data gathered during the spacecraft's last encounter with the Jupiter system early this month. In addition to playback, the spacecraft will pass through a distant Earth occultation late in the week. For about 18 hours on Sunday, Jupiter will be in the way of any attempts to transmit data from Galileo to the earth. As the spacecraft's signal slowly disappears behind Jupiter, the radio science team will measure the changes in the signal. These measurements will allow them to determine temperature and wind speed profiles in that local area of Jupiter's atmosphere.
The week starts off with the completion of playback of the high-time-resolution fields and particles observation of Jupiter's plasma sheet. This recording was taken while Jupiter rotated through one quarter (~2.5 hours) of its daily cycle (~10 hours). Other observations returned this week include a photometry observation of Callisto's equatorial region performed by SSI (Solid State Imaging camera), a global observation of Callisto performed by NIMS (Near Infrared Mapping Spectrometer), an observation of Adrastea performed by SSI, and the first of many observations of Jupiter's south pole region -- this one performed by SSI.
The bulk of this week's data playback, however, is dedicated to observations designed to monitor volcanic activity on Io. NIMS returns observations that search for and map hot spots, thermal anomalies and hot outbursts on the surface of Io. Other NIMS observations will provide data on chemical changes on Io's surface, while yet another set looks how volcanic activity on Io changes with time. PPR (Photopolarimeter Radiometer) also returns one observation that monitors Io for changes in its volcanic activity. Io observations returned by SSI are part of an extensive campaign designed to catch volcanic plumes in action. Ten different plume regions were observed during the last encounter. Each observation was designed so that the plume, if active, will be caught on Io's edge against a dark sky background. The regions returned this week are Kanehikili, Amirani, Malik and Prometheus.