# Cassini: What information could be gained from the 2017 impact with Saturn?

First of all:

• Will Cassini be operational in 2017 (pending no unforeseen equipment failures)?

• Power
• Communications
• ...
• What information could we gain?

• Properties of Saturn
• How to build more resistant spacecraft for future atmospheric descents and gas planet impacts
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I would bet that as long as the craft is functioning, that 2017 date will get extended. The three radioisotope thermoelectric generators (RTGs), will still be able to produce 600 to 700 watts of electrical power in 2017 (NASA page). –  Larian LeQuella Jan 8 '12 at 18:23
Is that (NASA page) a placeholder for a link? Would changing trajectory have to be decided too soon too late? –  TryTryAgain Jan 8 '12 at 18:28
Nope, not a placeholder, just where I got those figures from. :) As for a change in the trajectory, I would think that the 2017 dive in would require a larger delta V than just keeping it in orbit. Just a guess on my part though. –  Larian LeQuella Jan 8 '12 at 19:14
There's precedent in the Galileo atmospheric entry probe (which was able to transmit data to Galileo), and in Galileo's own death plunge into Jupiter. The former was of course designed for the purpose, and transmitted about 3.5 megabits of data. I don't have any information about data transmitted from Galileo's own final plunge. One difference is that Cassini will be the first direct probe of Saturn's atmosphere (it carried the Titan lander instead of an atmospheric entry probe). –  Keith Thompson Jan 8 '12 at 23:21
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## 1 Answer

There are two main science goals for the Cassini death dive into Saturn that I know of. One of them is simply higher scale imagery of objects closer to Saturn as it journeys inwards. The other is that it will fly between the planet and the rings, and based upon the radio signals coming back to Earth, we should be able to, for the first time, directly measure the mass of the rings to within around 1019 kg. This may seem pretty coarse, but there are several specific prediction papers (including one of mine ...) that estimates the ring mass in multiples of the moon Mimas, which has a mass of $3.8\cdot 10^{19}$ kg.

A third that I thought of a few hours after writing this is that the spectrometers on board should be able to sample the saturnian atmosphere during entry and send back detailed composition information, just as it did when flying through the plumes of Enceladus.

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