The following is a simulation for space shullte. The
It is a circular motion initially. i.e. $\frac{GM}{r^2}=\frac{v^2}{r}$.

You can click [b]fire[/b] button to apply an impulse to the space shuttle and watch how the trajectory changed.

The impulse will be fire at zero or 180 degree if the "next" check box is checked.