Today on Galileo - November 3, 1997
Today Galileo continues to travel on its orbit to a close fly of Europa. At about 2 AM Pacific Standard Time (PST), the spacecraft reaches a distance from Jupiter of 40 Jupiter Radii (RJ) or 2.9 million kilometers (1.8 million miles). The spacecraft will reach a minimum distance of 9 RJ or 641,000 kilometers (398,000 miles) during this encounter period.
The activity level remains low on the second day of the Europa - Orbit 11 encounter, the last encounter of Galileo's primary mission. The morning is spent completing activities that were started last night. Regular maintenance on the spacecraft's tape recorder is completed just prior to 7 AM PST. The Callisto neutral torus observation continues to execute in parallel with tape recorder maintenance because it is designed to return the data it collects in real-time. The data collected by the instrument is almost immediately (after some on-board packaging) transmitted to Earth and does not require the tape recorder's storage capability. This observation is performed by the Ultraviolet Spectrometer (UVS) instrument and is completed just after 12:00 PM PST.
The afternoon's activities only involve the continued collection of magnetospheric data by the fields and particles instruments. These data are collected at a rate of a few bits per instrument per second and are also returned to Earth in real-time. Late in the evening, the UVS instrument performs another observation of Callisto's surface. This one is performed at a solar phase angle of 70 degrees. At this solar phase angle slightly more than half of the moon's surface is illuminated by the sun. Once again, these observations of Callisto by the UVS instrument are designed to look for the presence of oxygen and hydrogen. The presence of these elements could provide clues as to whether there is any geologic activity, such as earthquakes, on Callisto.