Today on Galileo - February 18, 1997
As Galileo nears the Jupiter system, we see more science related activities on the spacecraft's daily schedule. After completing its remote observations of the Io Torus, the ultraviolet / extreme ultraviolet spectrometer combination turns its attention to Jupiter. The day is filled with observation of Jupiter's auroral regions performed by both instruments while maps of Jupiter's dark and bright sides are performed by the ultraviolet spectrometer alone.
The auroral observations will provide data at new longitudes of Jupiter's atmosphere. These data will allow scientists to determine the energy of the electrons that are falling from the magnetosphere into Jupiter's atmosphere, thus causing the auroral phenomena. The bright side maps are used to determine the distribution of energy (in the ultraviolet range of the electromagnetic spectrum) on a global Jupiter level. Finally, the dark side map, along with other observations, is used to map the distribution of hydrogen in Jupiter's atmosphere. Combined with measurements from previous orbits, this orbit's set of data will nearly complete the first full map of the distribution of hydrogen on Jupiter's dark side. These hydrogen distribution maps are used to determine and study the transfer of energy and dynamic processes in Jupiter's upper atmosphere.
Toward the end of the day, the first Io observation of the encounter is performed by the camera. A plume monitoring observation of the volcano Pele, it is part of the continuing campaign to map and observe active volcano plumes on Io's bright limb against the black sky background.
Also today on Galileo, in the morning, the tape recorder, having completed its conditioning activity just yesterday, is positioned at its starting location for this encounter. If you visited Today on Galileo yesterday, you would know that the last orbit trim maneuver prior to the Europa encounter was also scheduled for around 10 a.m. (PST). It turns out that the spacecraft's path did not require a final fine tuning and this maneuver has been canceled.
Finally, at the end of the day, the Galileo team is scheduled to transmit the set of commands that will instruct the spacecraft through the latter half of the encounter period. This set of commands will start to execute late Thursday and will continue through Saturday evening.