Question: struggling to use DEplot with a system of 4 differential equations

Ive been trying to plot the following system



With these initial conditions (Also G*M=1)

ics:=[x(0)=1, y(0)=0,vx(0)=0,vy(0)=1];

I use this command to try and do this

with(DEtools):
DEplot(subs({G=1,M=1},satODE1),{x(t),y(t),vx(t),vy(t)},t=-2..2,ics,scene=[x(t),y(t)],scaling=constrained);

But I get this error message

Error, (in DEtools/DEplot/CheckInitial) too few initial conditions: [x(0) = 1]

Which I find odd because I have an initial condition for each variable

Im not sure what makes this different to other DE's Ive plotted other than having more equations in the system

 

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