Flight Question DEEPSTAR orbiting Jupiter PEA 14500 km; IMFD TO SATURN: anomalously high vector velocity VS course plan

[robertostocchetti82@gmail]

Good morning everyone,
as indicated in the title and shared from the following pictures; I am in Jupiter orbit and I plan the trip to Saturn.
Using IMFD 5.7 & Orbiter 2016, when I plan the target intercept I found a set of dates to minimize the dV, for example the first MJD 64875-68476: however, a few hours before departure adjusting the departure date with scenario editor, when I launch the orbit eject program based on course program shared, the dV eject vector is much much higher than expected! about 10 times more and I don't understand the reason.

Using the trajectory planner software I defined a new set of optimal dates: MJD 65377-68751 with a dV of only 2002,3 m/s to prove if something wrong with the data planning. However, a few hours before departure adjusting the departure date with scenario editor, when I launch orbit eject program I found a velocity vector of 30607.54 m/s insted 2002,3 m/s!!! (dVf=4492 m/s; dVP=15536.18 m/s & dVi -25985.88 m/s); verifying there are only 5,51 degrees of relative inclination with respect to Saturn, not so much to explain a dVi so big light that!

In the attached pictures you can't see it, but when I update the time to eject TEj in orbit eject program equal to the course program (left screen IMFD), the values of the velocity vector remain unchanged (i.e. setting 30ks or 40 ks at launch instead of 0s almost nothing changes, the vector remains always above 30000 m/s).


Have any of you noticed this kind of anomalies or understood for what reasons they are generated and how to solve it?

Thank you very much!
Happy interplanetary navigation to all!

 

[Pioneer]

Can you adjust your time to eject to be parallel to your current orbit? Also, it could be the gravity of Jupiter that may be having an effect on the amount required to burn out. I usually avoid getting so close to Jupiter.

 

[robertostocchetti82@gmail]

Can you adjust your time to eject to be parallel to your current orbit? Also, it could be the gravity of Jupiter that may be having an effect on the amount required to burn out. I usually avoid getting so close to Jupiter.

hi, thanks for your reply, with the original mjd orbit 62355 (dv 43,93 K m/s) , after change the pea to 1Gm to reduce the gravity effect is better, about 10000 m/s instead 2000 m/s but always 5 time more the course value!

 

[Pioneer]

hi, thanks for your reply, with the original mjd orbit 62355 (dv 43,93 K m/s) , after change the pea to 1Gm to reduce the gravity effect is better, about 10000 m/s instead 2000 m/s but always 5 time more the course value!

Try to adjust the eject trajectory to be as parallel to your current orbit as possible to further reduce. If it is still higher, it's probably because you're doing a decent amount of either plane change or inward/outward burning.

 

[Arvil]

Many times if you’re doing off-plane orbit and Saturn is pretty far off Jupiter’s plane, it’ll need a pretty high inclination transfer to match up with Saturn. Might be better two-plane, fly along Jupiter’s plane until you get to the Jupiter-Saturn node, then do a plane change to Saturn’s plane. Saves fuel. Or, plan the orbit timing for when Saturn happens to be at or near the node where Saturn crosses Jupiter’s orbital plane.