The Orbit with calculation flaw by following algorithm: 
a = -G*M/(R²);

ax = a*X/R;   ay = a*Y/R;
Vx = Vx + ax*dt;  Vy = Vy + ay*dt;
X = X + Vx*dt;  Y = Y + Vy*dt;
Start values:
dt = 0.2; X = 0.6, Y = 0;
Vx = 0, Vy = 1.63, ax = 0, ay = 0;

You may change this values!
 

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