Note: I am posting my old blog entries from elsewhere on the internet. This entry was originally posted on 10/09/08.
The Enceladus flyby happened today; we won’t get the data down until tomorrow. In the meantime, various team members have posted at the blog, and there’s a cool movie of what the flyby looked like if all went as planned. From my coworker Amanda’s post on the blog, here’s what you are seeing in the movie:
“The left-hand panel shows the spacecraft and its relationship to Enceladus and will indicate the view of the “prime” instrument by showing its viewing frustum in the color corresponding to that instrument. The upper right panel shows the fields-of-view of the remote sensing instruments (i.e. the cameras and the imaging spectrometers), and the lower right panel shows the “active” field-of-view, since at any time, one instrument is “prime” (though other instruments may be simultaneously taking data, while “riding along”).”
That whole thing with prime versus riding along is this: the instruments are all fixed onto the viewing platform. If you want to move where an instrument is pointed, you have turn the whole damn spacecraft. Some of the instruments were lined up so that they are looking in approximately the same direction, which makes things a bit easier, but some are not. For any given period of time on Cassini, one instrument is designated as “prime” which means they get to decide where the spacecraft is pointing. Any other instruments that can get useful data will be turned on, and are considered to be “riding along” with the prime.
You can see in the movie how the fields of view of different instruments pan across the surface of Enceladus as they try to get measurements of as many things as possible. Some instruments pan across more than the surface, because they want to measure the surrounding space, including the plume of material in the geyser.
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