The defining equation for simple harmonic motion is such
$$a=-ω^2x$$
When we find the centripetal acceleration of an object in orbit we use the formula
$$a=ω^2r$$
As a consequence of the accleration being $\frac{v^2}{r}$
The two formulas for acceleration look extremely similiar, and displacement $x$ is essentially the $r$. So then what has happened to the negative sign?