NASA has added two years to the Cassini mission to Saturn.
Where to go?
What to see?
To prepare for this extended journey, engineers had to chart some tricky maneuvers trying to fulfill the wish lists of 200 scientists
Nathan Strange, Cassini Tour Designer:
The spacecraft's going. You have a locomotive speeding down the track? Well they haven't built the railway yet and we're up front laying track.
It's a lot like, if you're in TripleA and you go to get a Trip Tic at the counter. Someone sits there with a map and draws out with a highlighter where you're going and plans out the trip with you.
So the scientists are on one side of the counter telling us what they want to see and then we're with the map, mapping out a route and saying, well how's this?
For the last year and half, Cassini tour designers have been working at breakneck speed on plans for an extended mission.
It's not what you call a low stress job by any means.
They essentially have laid down on the table what they want as far as science goals and science objectives.
We come back, we take that off for a couple of months, apply astro dynamics.
The people who want to look at the rings want to be up high and look at the rings. The other people want to be down in the same plane with the rings where they can visit all the other moons, and that’s a huge tug a war.
Jonathan Lunine, Cassini Scientist:
So what the tour designers have to do is take all of these different inputs from hundreds of scientists who say we have to observe this, we want to look at that and put that together into a very compact new tour of two years.
It has seven Enceladus flybys, at or below 2,000 kilometers, two at 25 kilometers.
This tour has 26 Titan flybys and has 2 high northern ground tracks.
The last Titan flyby is over here, so this is where it reaches the ring plane, so it kind of moves over a little bit.
We show a variety of different tours that are kind of in different flavors. One makes the rings people a little bit, more happier than the moons people.
Okay, goals for this PSG, obviously for us, we think it's select the final tour.
They rated the tours in terms of red –unacceptable, yellow-acceptable and green-acceptable.
But it sounds like 6h9 and 8 should either both be -- both be red or both be yellow?
Now all the candidates are out there and they've got to pick one.
6h9--3 greens, a lime and a red.
And in the end, it was shades of green.
We will continue this in executive session.
The science team leaders made the final decision.
And the tour was called, this is kind of hard to pronounce,
"PF6H9", but that's the name of this hybrid tour.
Cassini's travel itinerary includes 60 additional orbits of Saturn, studies of the rings, the magnetosphere, 26 flybys of Titan and close encounters with other exotic moons.
And that’s real gratifying that it was a hybrid tour that took the best of a lot of the different tours that we had been designing.
The Cassini mission to Saturn has revolutionized our knowledge of the ringed planet and the best may be yet to come.
To be able to fly through space in a complex place full of moons and rings and dust and so on. And to be able to navigate this space in such a way as to give Cassini a chance to make all the discoveries that the scientists on the mission would like to see happen. I don't think of it as a wish list. I think of it as a list of potential new discoveries that will be in the textbooks forever, and these guys are the ones who will make it happen.