Galileo Mission Status - September 8, 1997
PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov
Jupiter's atmosphere has been the starring attraction of much of Galileo's activities this week. The spacecraft's standard cruise activities paused for a series of atmospheric observations, being conducted as part of the observation campaign in this extra long cruise following the Callisto-9 encounter. These atmospheric observations were delayed until this part of the orbit when the spacecraft is on Jupiter's dark side and only a small part of the planet seen by Galileo is lit by the Sun. These conditions cause the scattering of sunlight by Jupiter's upper atmospheric layers, allowing scientists to study the size and quantity of particles in the planet's upper atmosphere. Regions that are being investigated this week include the Great Red Spot and hotspot regions by the Near-Infrared Mapping Spectrometer (NIMS), and limb images taken at various latitudes by the Solid State Imaging (SSI) camera. The Ultra-Violet Spectrometer (UVS) will also participate in the SSI observations.
Before the pause for the atmospheric studies, spacecraft playback included the recorded Callisto-9 encounter observations of the moon's multi-ringed Valhalla region taken by Galileo's near infrared mapping spectrometer and solid state imaging camera, as well as a polarimetry map from the photopolarimeter radiometer. Other recorded encounter observations played back include a "plume head" cloud region, images of the minor moons Metis and Adrastea, and a global map of Ganymede, including a region on its surface where the terrain color shifts from dark to light.
After Galileo finished its atmospheric observations, playback resumed of recently recorded observations of Jupiter's magnetotail, the area of the planet's magnetic field that is blown by the solar wind. Playback also includes observations by the near infrared mapping spectrometer of the Great Red Spot and portions of Jupiter's northern and southern hemispheres. Next week playback will be paused the seventh and last time in this orbit to record more observations of Jupiter at the high light scattering angles.
Galileo's next encounter will by a flyby of Callisto on September 16. The spacecraft's primary mission will end on December 7 of this year following data return from the 10th and final encounter of its primary mission, a Europa flyby on November 6. An extended mission will continue for two additional years so the spacecraft can conduct an intensive study of Europa, with the goal of achieving one or two close flybys of Io, depending on spacecraft health, in the fall of 1999.
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