This Week On Galileo
September 28 - October 4, 1998
This week Galileo continues to process and transmit to Earth data stored on its onboard tape recorder, recently acquired during the sixth encounter of its Galileo Europa Mission. Data playback is interrupted twice this week. On Monday, it is interrupted to perform a standard gyroscope checkout and, on Friday, to perform a flight path correction, if necessary. In addition, Dust Detector measurements of small dust particles moving outward from Jupiter continue through Thursday.
This week's playback data focuses on observations of Europa, but also contains a few observations of Jupiter and its rings. The Jupiter observations are returned by the photopolarimeter radiometer instrument and contain data that will be used to characterize the temperature structure and thermal properties of Jupiter's Southern equatorial, tropical and temperate belt regions. The spacecraft camera returns images of Jupiter's rings taken at two out of three different lighting conditions. The information contained in these observations will allow scientists to get better ideas of the number and sizes of the particles that make up the rings.
Observations of Europa are returned by all four remote sensing instruments: the near-infrared mapping spectrometer, the ultraviolet spectrometer, the photopolarimeter radiometer and the spacecraft camera. The near-infrared and ultraviolet spectrometers return a joint observation in which they capture data about Europa at a global scale. The photopolarimeter radiometer returns a series of thermal observations of Europa's night side, designed to allow scientists to increase their knowledge of the formation, composition and age of Europa's surface. Finally, the spacecraft camera returns a pair of observations that capture regions near Europa's terminator (line dividing Europa's lit side from its dark side). These images contain pull-apart zones, mottled terrain, banded regions, dark spots, cycloidal bands, Agenor Linea and Astypalaea Linea. All of these are terrains that are considered to be the best evidence for the existence of a liquid layer under Europa's surface.