It might work if you had energy being supplied by interaction with an external force, space tethers being the obvious example, where you're getting 'free' energy from gravity and centrifugal force -- in practice you're presumably slowing the rotation of the planet slightly, so it's not a perpetual motion machine. You can 'harvest' energy by doing a slingshot around a planet, likewise imparting energy to the projectile at the cost of a tiny bit of the planet's own momentum...