Cacini And Saturn

[ElPelado]

As some of us may know, Saturn was closer to us in New Year's eve than last 30 years. Is because of this that the cacini was sent when it was sent? I mean, like the MER and MEX that were launched taking advantage of the "small" distance between mars and earth on agust.

[JackHiggins]

I think it was more the positions of Earth, Venus and Jupiter, rather than saturn which caused it to be launched when it was. Since we don't have powerful enough rockets to go directly to Saturn currently, Cassini needed 2 Venus, one Earth and one Jupiter gravity assists, to slingshot it to saturn.

Since saturn is so far away compared to Mars, the relative distance between perihelion and aphelion, from our point of view, is much less. If Cassini had missed it's launch window, NASA would just have had to wait until the next favourable alignment of planets for gravity assists, rather than waiting for saturn to be near opposition again.

Hm.. Does that make sense?!

[ElPelado]

Yes it does. I havent thought about that...
Thanks for the explanation.