Today on Galileo - May 4, 1997
Today, Galileo starts its next set of observations of the Jupiter system. Ganymede is the featured satellite for this orbit. This will be Galileo's last close flyby of Ganymede -- scheduled to occur Wednesday morning at an altitude of just under 1600 kilometers. The encounter period also includes a non-targeted flyby of Callisto on Tuesday morning. The set of computer commands that starts executing today will run through late Tuesday. The second set, transmitted to the spacecraft in the next couple of days, will run through the end of the encounter period next Sunday.
Today's observation schedule is relatively light. The fields and particles instrument survey of the Jupiter magnetosphere continues through the encounter and into cruise contributing to the second "mini-tour" of the orbital tour (recall that a "mini-tour" is a portion of the fields and particles survey that is more than one complete orbit in duration). The UVS (Ultraviolet Spectrometer) instrument performs remote observations of the Ganymede neutral torus. The neutral torus is believed to be formed when neutral (i.e. with no electrical charge) particles are stripped off of Ganymede and then remain trapped in the same orbit as Ganymede. Starting late in the afternoon and continuing into early evening, the UVS observations are interrupted by the final orbit trim maneuver prior to the close Ganymede flyby.