# Launch vehicle trajectory tool for ascent phase to orbit using PYTHON

Currently, I am developing a trajectory optimization tool for launch vehicle from lift-off to orbit using python for my project. Since I'm new to optimization problem, I am finding it hard to understand the different maneuvers in each phase of flights and how to program those maneuvers in different frames.

Can someone please give a clear idea about defining Equation of motions for different phases of flight with maneuvers and reference python code deals with similar problem.

• You may have an easier time finding reference code in MATLAB – CourageousPotato Aug 20 '19 at 7:04
• Can you please specify some sources for them – Astrolien Aug 22 '19 at 17:35
• I do it in GMAT (but I program liftoff and ascent phase myself (in the language very similar to MATLAB)). GMAT does all optimization work. It looks like You can find and see GMAT source codes (in C/C++). I'm not sure about Python. – Peter Nazarenko Aug 30 '20 at 19:25
• @PeterNazarenko How did you program maneuvers during the ascending phase in your code? GMAT source code has ascenting phase of launch vehicle? – Astrolien Sep 4 '20 at 16:53
• @Astrolien No, GMAT doesn't calculate ascend phase itself. I do it manually in script by means of "while" or "for" statements. Something like this while ship.Earth.Altitude <= alt1 some stuff EndWhile; – Peter Nazarenko Sep 4 '20 at 18:16