TransX Transfering eject plan to escape stage

[Shadow Addict]

I set up an eject to Venus with a Cl. App of about 25.98M that would sling me back around to a close Earth approach. I launched and got my RInc down below .01. Now I'm trying to set up my eject plan, and I'm finding it impossible to get get my Cl. App anywhere under 200M. Is there any way to get my plan transfered more precisely? Is there even a point to getting a precise plan made before launch if it'll just have to be messed with before the eject?

 

[agentgonzo]

The model that TransX uses for the solar system (perturbed patched conics) is not super-accurate. As such, the predictions will change as you travel between spheres of influence of different bodies. The behaviour that you are experiencing is totally normal. The 'standard' operation of TransX is to set up a 'fairly' accurate plan (PeD seems to change more than the inclination) and then do a coure-correction burn as soon as you move to the next stage in TransX, and then one every time your time to the encounter halves (or as you deem necessary)

 

[flytandem]

I set up an eject to Venus with a Cl. App of about 25.98M that would sling me back around to a close Earth approach. I launched and got my RInc down below .01. Now I'm trying to set up my eject plan, and I'm finding it impossible to get get my Cl. App anywhere under 200M. Is there any way to get my plan transfered more precisely? Is there even a point to getting a precise plan made before launch if it'll just have to be messed with before the eject?

I don't really understand the question because you said you set up an eject plan, then after you launched you are then trying to set up an eject plan.

You asked what is the point of setting up a precise eject plan if it needs to be changed after launch.

What I generally do is first set up the plan as you did. Launch as you did and you did well BTW to have the rel inc down to .01 degrees.

The plan is to get you in orbit approximately in plane and at a time for a possible trip to the destination planet. Once in orbit you will see a required delta-v and a graphic of the hyperbolic escape trajectory. Then do the following...

Set up a maneuver. Maneuver=On
Add prograde to match the required delta-v.
Advance the date to visually lay your maneuver trajectory exactly on top of the eject plan trajectory.
Turn off the eject plan by going to the next stage and making the prograde, outward and plane change values = zero.
Now in stage 1, tweak the date and prograde as well as outward and plane change to make it precise to your destination as shown in stage 2 and 3.
Use the maneuver target to aim and burn as in any maneuver.

 

[Shadow Addict]

I'm sorry, I didn't ask the question very well. I was wondering if there was a more precise way to set up the maneuver to be exactly like the eject plan. I'm pretty sure I wasn't putting in the right variables for the maneuver, I'll go try again.

BTW I just completed my first real slingshot using your Voyager Flight scenario. What a satisfying feeling!

 

[flytandem]

If there is no easy way to get the maneuver to make a cl app near your target planet and you are really close in the orbit I then should ask if the date value of your original eject plan is anywhere near the date that you are now in orbit.

The setting up en eject plan is a way to rough out the date (within a day or two) and to get somewhere in the correct orbital plane. The plan will give you a required deltav and show a graphic of the eject location.

Then the maneuver prograde deltav and swinging the date to place the graphics of the trajectory on top one another is a start. After you delete the plan you now start the real eject burn planning as a maneuver. Yes tweaking of all variables should be considered.

 

[Shadow Addict]

I don't think I was messing with the variables aggressively enough the first time, because I tried it again and I was able to get my maneuver set up fine. Thanks for the help!

 

[flytandem]