Question How to find closest collision point on sphere to surface

I'm trying to find the closest collision point on a sphere to the surface as you can see here:


I've already tried Physics.SphereCast and Physics.SphereCastAll but both don't seem to work for me.
(Maybe because I've set their direction value to Vector3.zero?)

Is there another way I could achieve this?

 

Calculate the closest point on the surface to the center of the sphere using this: https://docs.unity3d.com/ScriptReference/Physics.ClosestPoint.html

Then it's just a matter of projecting the point to the surface of the sphere.