A 100 km high tower is erected on a pole, e.g., the north pole. A Sling mounted on top of the tower rotates about a vertical axis. The axis of sling rotation will precess unless the tower is erected on a pole. The minimum mass of a steel sling is greater than the mass of the Earth! Since high-strength plastics are susceptible to space radiation and thermal fatigue, they are not an option. No bibliography. Jerome Pearson proposed the idea.