Spherical cows on the other hand have to move with orbital velocity at least, or they fail to stay in vacuum for long and splash.

Cows don't roll - they are frictionless so just glide over the surface smoothly.

Not with that attitude

It takes a stupid cow, but when they can climb mountains as they do it is not inconcievable that one can roll down.

(I was suprised to see a cow jumping up on a ~3m rock ledge like it was nothing)

Or on shabbos