
I'm trying to do what I would think would be easy - I've got a spacecraft in LEO, a large tank and thrusters, and it's trying to make a close pass of Venus. My actual scenario is more complex, but this is just for starters. So I have to solve for two things: how long to wait in orbit to do the burn (so that it'll be pointing in the right direction), and how high of a delta-V it needs to do the burn for. I've tried all sorts of combinations, and all it ever seems to want to do is oscillate by MaxStep, back and forth, never trying any values in-between. This happens whether I include one variable in the optimization or both, regardless of what parameters I choose in the Vary command, and so forth. I've been working on this for days and I've gotten nowhere

Here's one of the random variants of the Mission Sequence tried:
- Code: Select all
BeginMissionSequence;
%Propagate 'Prop VTE' prop(Transit) {Transit.Earth.Periapsis};
Target 'Venus loop' DC1 {SolveMode = Solve, ExitMode = SaveAndContinue, ShowProgressWindow = true};
Vary 'Vary position delay' DC1(duration = 7000, {Perturbation = 0.0001, Lower = 0, Upper = 8000, MaxStep = 400, AdditiveScaleFactor = 0.0, MultiplicativeScaleFactor = 1.0});
Vary DC1(VTOI.Element1 = 3.7, {Perturbation = 0.0001, Lower = 0.0, Upper = 34.9, MaxStep = 0.25, AdditiveScaleFactor = 0.0, MultiplicativeScaleFactor = 1.00});
Propagate 'Prepare position' prop(Transit) {Transit.ElapsedSecs = duration};
Maneuver 'Apply VTOI' VTOI(Transit);
Propagate 'Prop to apoapsis' prop(Transit) {Transit.Earth.Apoapsis};
Achieve DC1(Transit.Venus.RMAG = 42165.0, {Tolerance = 100000.0});
EndTarget; % For targeter DC1
I'm attaching the full file, although it's spammier, and contains random things I've tried and since commented out.
I'm using R2016a (64-bit), build date Oct 6 2016 09:51:25. Thank you for any tips you can provide!