Tuesday, September 27, 2005

I33 - Galileo's Last Snapshots

In January of 2002, Galileo swooped down on the Jovian system, the last time it would do this with cameras on. There was a hard fought campaign to fund this, led by Jason Perry, due to the fact that it would allow photography of portions of Jupiter's moon Io that had never before been seen at close range.

However, this was not to be. Galileo would suffer a radiation-related glitch, common during the later portion of the mission, causing it to miss the entire Io imaging sequence. Largely this orbit was a loss, and it drove the final nail in the coffin of imaging on Galileo's final orbit, A34, during which it would fly by tiny Amalthea. In addition to funding problems, it was decided that turns for imaging would make it to likely that the spacecraft would shut down before the flyby.

A few views did get returned from the I33 orbit. They stand as a last testament to Galileo's camera. It brought us some unforgettable glimpses of the Jovian system. However, we only saw a small fraction of what we would have, had Galileo's main antenna opened properly.

This view shows the top of the red spot on the limb of the planet. It is amazing to see all the intricate paterns in the clouds.

This view, taken as the red spot rotated further onto the disk, is a false-color view, generated from various infrared views. It certainlys shows great contrast between the spot (which appears blue here), the cloud belts, and the thunderheads that can be seen on the lower left.

This final view shows the spot rotating across the terminator, into the Jovian night.

On its way in and out, Galileo took these two snapshots of Amalthea. The purpose was to improve navigation for the upcoming flyby of this little moonlet, but such images also help in the study of the shape of irregular worlds.

Galileo also took a series of views of the Jovian cloudtops much further into the infrared than its camera could see, trying to study the temperature and composition of the clouds. This one shows Io, the bright spot to the left of the disk, and its shadow on the cloudtops, just left-of-center. It would be Galileo's last look at Io, and a bittersweet one, considering what might have come from this flyby.

This final image is of Europa. Taken to study the way Europa reflects light when it is viewed at a "full moon" illumination angle - called opposition surge - it is Galileo's last view of a world where it discovered an ocean beneath the icy surface, and a world that Galileo turned into a top priority for future exploration.

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