Today on Galileo - September 6, 1996
Galileo's closest approach to Jupiter's moon Ganymede will occur today at noon PDT. At that time, the spacecraft will pass only 262 km over Ganymede's surface (which is closer than the Space Shuttle orbits the Earth!). For 4 hours around this "closest approach," the instruments will be making intense measurements of Ganymede's surface, atmosphere, and magnetic environment. Galileo will pass over the moon's north pole at a speed of 8 kilometers per second.
The surface structure and composition of Ganymede will be studied in depth by the imaging camera and NIMS instruments. The same Uruk Sulcus region that was imaged in the Ganymede 1 flyby will again be observed, and the pair used as a stereo image to determine heights of the features in the region. The camera images will have resolutions from 60 to 300 meters during this flyby. The NIMS and UVS instruments will search for a possible atmosphere on Ganymede. The Fields and Particles instruments will study the magnetic field around the moon, studying the interaction with Ganymede of dust particles, plasma, and the magnetic field of Jupiter.
Io will also be the focus of attention for Galileo today, as the spacecraft passes within 441,000 km of that moon. This morning, the UVS instrument will spend 4 hours observing Io's atmosphere and torus, looking for molecules that are thought to flow from the volcanic eruptions on Io's surface. Later in the day, the imaging camera and NIMS instrument will look at the moon "face on" for new volcanic deposits.