The Galileo spacecraft is scheduled to begin today what’s described as a daring low-altitude flyby of Jupiter’s moon Io. The craft will pass within 186 miles of Io’s surface (closer to the surface than the International Space Station is to Earth’s), passing over the moon’s south pole. Closest approach will be tomorrow evening. On its way, it will pass by the moon Callisto tonight and the scientificly-popular Europa tomorrow morning.