Matlab 2-D Simulation for TLI (Trans Lunar Injection) "Basic Orbital Mechanics" Hi Everyone, I have been assigned a project in which I am to program in matlab the solution to the 3-body problem, but in 2-D with a couple assumptions. 1) Earth and Moon are stationary. 2) Mass of spaceship is constant 3) Spaceship initially in circular orbit 20km above earth Here is my problem, the school does not offer a class in matlab programming. So I looked all over for some sample codes I could modify. I found one that seems to be a great start but I do not fully understand it. I was hoping someone on here could help. I file 'orbit.m' call upon 'orbitode.m' which I believe is a standard example script for matlab. However I keep getting the error 'no default parameters set' as well as two others. Can someone please please help me figure this out. If I could just get the file 'orbit.m' working I think I can get the rest. Also if anyone would like to briefly explain what is going on i.e. how matlab is working or what exactly it is doing that would be great! Thanks in advance for all your help.