General Question Titan Orbit Project Help

[flytandem]

So simple. Love it. !!!:thumbup:

 

[RGClark]

:hmm:I don't know Rob. 5km/s to get from Titan to Jupiter sounded a bit much. But I saw that for the sling, you dropped well below Jupiter's orbit and then used the planet as a "brake".

Back in this thread, you used 3.78 km/s for a Titan to Mars direct trip, so I think that a combination of that and the plan you posted would be much cheaper. Titan→Jupiter sling→Earth, without falling in Saturn's well. I'll set it up and see how it goes.



---------------------------EDIT-------------------------------

Yeap, this solution uses a little bit less than half the Δv (2.4 km/s) for Titan to Earth via Jupiter.
It was fun to setup, because I had to start from the middle to the end and then setup the middle to start plan.

First I found a Jupiter→Earth window and that had Jupiter in a convinient position for a low Δv Saturn→Jupiter transfer. Then I setup the Saturn→Jupiter transfer and the Jupiter→Earth slingshot, which also needed a 0.5km/s burn at Jupiter Pe.

Then I worked my way back to the escape plan where I setup the altitude at the height of Titan's orbit around Saturn. This helped me to find the date for the eject maneuver at stage1. Since I used very little plane change in the transfer, I placed the DG at 0 degrees Ecliptic incl. around a 675km orbit around Titan.
The cost for the eject was 1,9km/s. I had to turn the "advanced on" and the "autoplan off" on all the stages except the last.

Here is the preliminary plan 1/4 orbit away from the first burn. Here normally, I set up a second instance of transX, add the same stages and only setup the same maneuver on stage1, so I can see if the trajectory after the maneuver agrees with the plan I have setup. Unfortunately, exiting a scenario with two instances of transX, gets them mixed up and the plan is lost...

Are you saying that you can get an escape from Saturn's deep gravity well, ca. 35 km/s escape velocity, at a delta-v much less than that? Is it by the Oberth effect?

Bob Clark

---------- Post added at 09:01 PM ---------- Previous post was at 08:55 PM ----------

http://gmat.gsfc.nasa.gov/

I've had my eye on this tool for a while, but haven't cracked into it yet. Supposedly it will allow you to design and visualize complex mission profiles and capture/process a lot of relevant data (with appropriate matlab exports, etc) The kind of thing you want if you're thinking about planning a real mission.

Orbiter still gives you the feeling like you "actually did it", there's no topping that!

Thanks for that.


Bob Clark

 

[dgatsoulis]

In my solution I didn't use the Oberth effect, but flytandem did in post #17

The escape velocity is not a constant but gets smaller as the orbital altitude increases. Vesc=sqrt(2GM/R)

Check the thread you started at the math & physics forum to see the calculations for a Europa-Earth journey.

 

[RGClark]

I like it and also the way you have assembled the screen shots.
It makes sense that having a slow encounter at Jupiter that you need to set up a maneuver in the gravity well (or whatever amount of well you get in the sling).
Looks like you were just doing a plane change in the Ap of the first eccentric orbit at Saturn. Mixing in some retrograde would drop the Saturn Pe making a more effective gravity well burn. But you are easily able to do this as a choice when setting up that burn.
The plan I flew was even more eccentric in that first orbit taking nearly 300 days longer longer but by doing this it reduced the plane change deltaV and allowed a lower deltaV reduction of Saturn Pe which then because of being so close to Saturn, allowed very little deltaV needed to eject to Jupiter. Since it is a very effective Pe eject burn, the difference between arriving slowly to Jupiter (type 2 transfer) as you are setting up and heading to a faster encounter (type 1 transfer) is likely just a few m/s in the Saturn eject burn. This would eliminate the need for the burn at Jupiter and also gets the ship home about 5 years sooner.

How long is the trip from Saturn to Earth with the close Saturn swing by and how long without it?


Bob Clark