Note: I am posting my old blog entries from elsewhere on the internet. This entry was originally posted on 4/27/10.
In 8 hours (at 00:10:00 UTC), Cassini will fly 100 km above the surface of Enceladus, passing deep through the plume at the south pole. I’ve talked about this flyby a bit on this blog, and in more depth over at Beyond the Cradle. This is the flyby that I have seen from start to (soon) finish, and worked very hard on. I even won an award for my work on it!
We won’t have any pretty press pictures, since we are leaving the cameras off. The camera fields of view point in a different direction on the spacecraft than the radio antenna, and turning Cassini back and forth to get pictures and then radio science data puts stress on the wheels (gyros) that keep us oriented. Since we are already stressing the wheels by flying through the heart of the plume, we agreed to stay fixed at one attitude during the entire flyby.
We’ve already started the flyby, and are approaching Enceladus. Cassini has pointed the antenna at Earth, and the radio science team is listening to the tracking signal. As we go past Enceladus, they will look at how the doppler effect changes the tracking signal to pull out what the gravity field at Enceladus is like, which in turn tells us what is going on inside Enceladus. Right now, they are getting a baseline of the tracking signal’s behavior for comparison.
There won’t be any answers right away – to get a good handle on what is going on, we need several gravity passes at different latitudes, and those are still coming up. However, this was the most important pass, and the hardest one technically to do. I will never work with the gravity data itself, and I am unlikely to ever be a coauthor on a study about Enceladus, but there is a part of me that will look at any paper that comes out about the internal structure of Enceladus, and think – I made that happen.
More info here.
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