Question Sphere of Influence

[dkluempers]

I am attempting to do the UCGO Tethys to Titan scenario. I have tried using IFMD but have not been getting solutions that make sense to me (it is most likely me not understanding things). I had setup a Target Intercept to Titan and it look reasonable.

But I just happened to bring up Map in another MFD and tie it to the other MFD. It did not show the plan at all. I zoomed in to Tethys and noticed that it shows the Sphere of Influence to be inside the Moon. I have a sneaky suspicion that is why I am not able to get a correct solution and why as soon as I life off from Tethys and go Prograde it immediately switches to Saturn.

Given that it is correct that the Sphere of Influence can actually be below the surface of the moon what should I use in IMFD to handle this?

Thanks gentlemen.

Dave

 

[TMac3000]

I ran into this on Miranda out at Uranus a while back...
Tethys has almost no gravity...so little that the computer cannot pick it up, to give you a vector for surface flight. You can't get into orbit, that little rock is just too weak to hold on to you. If you want to land, you'll have to eyeball the descent manually--it's more like a docking than a landing

 

[sorindafabico]

the Sphere of Influence can actually be below the surface of the moon

Yes, it happens to Phobos, Deimos and a handful of gas giants' moons.

what should I use in IMFD to handle this?

Fast solution:

1) Lift off.
2) Using Saturn as reference, change your apoapsis (relative to Saturn). If you're going to Titan, increase its value. Not much, just enough to keep away from Tethys. Be careful to avoid a collision with Tethys while changing your apoapsis.
3) [optional] Circularize the orbit in ApT=0.
4) Use the Course tool to plan a target intercept to Titan.