This Week on Galileo
February 12 - 18, 2001
A quiet week for the Galileo spacecraft
It is going to be a relatively quiet week for the Galileo spacecraft. On
Friday, the spacecraft performs standard maintenance on its propulsion systems.
Other than that, playback of the data stored on the on-board tape recorder
continues. Most of the week is taken up with a continuation of the Fields
and Particles data collected during the few hours surrounding the closest
approach of Galileo to the satellite Ganymede last December 28. Then if all
goes well, sometime Friday we will begin to see some of the remote sensing
instrument data taken during the encounter. First will come some
Photopolarimeter-Radiometer data of areas on the side of Ganymede facing
the Sun. What is special about these measurements is that at the time they
were taken, the entire satellite was in Jupiter's shadow. By seeing how
quickly or slowly different areas cool down after a few hours in the dark,
scientists can tell something about the fine structure of the surface.
Also, pictures of Ganymede taken while the satellite was in shadow should
give us a view of the aurora on the satellite, showing how charged
particles circulating in Jupiter's magnetic field interact with Ganymede's
own magnetic field and collide with the satellite's tenuous atmosphere. The
best time to catch the faint glow of an aurora is at night, and what better
artificial night can you get than when a planet the size of Jupiter is
blocking the Sun?