This Week on Galileo
April 19-26, 1999
Galileo's radio communications are once again normal and reliable after three weeks in which the Sun was positioned between the spacecraft and Earth. During this period, solar activity added interference to Galileo's radio signals and was capable of corrupting the information contained within. With normal communications restored, the spacecraft spends this week returning science data acquired during Galileo's February flyby of Jupiter's moon Europa. The data is stored on the spacecraft's onboard tape recorder.
Also during this week, flight team members will update software in the spacecraft's computer. This new software will allow the spacecraft to recover autonomously and continue executing commands in the face of an anomaly situation known as an erroneous power reset signal. This anomaly is believed to be caused by the accumulation of debris in the electrical connections between Galileo's spinning and non-spinning sides. The power reset signal occurs when enough debris have accumulated to cause an electrical short. This anomaly occured in July and November of 1998, with prior occurrences before 1993.
On this week's playback schedule, we find three observations. The first is returned by the Near-Infrared Mapping Spectrometer and was designed to differentiate between the possible crystalline forms of water ice on Europa. Detection of forms other than the expected hexagonal ice could provide scientists with evidence of geologic activity on Europa. The second is returned by the Photopolarimeter Radiometer. It was designed to obtain polarimetric measurements of Ganymede's surface, which will provide information about the texture and composition of the surface material. Finally, the Near-Infrared Mapping Spectrometer returns an observation of a region of Jupiter's Northern Temperate Belt. The observation will provide measurements of the composition and thermal properties of the region.
For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page.
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| Comments and suggestions about this home page may be directed to gllbug@jplpio.jpl.nasa.gov Last updated: April 19, 1999 |
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