Institute for Advanced Study/Princeton University Joint Astrophysics Colloquium

General Relativity is one of two foundational pillars of physics, yet gravity is the most weakly tested of the fundamental forces. Using the pristine solar system as a laboratory, we bump into this pillar to see if it might fall. This talk will describe many facets of the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) and how we can push an order-of-magnitude advance on our knowledge of fundamental gravity. Preliminary results from a new Absolute Calibration System will be highlighted, which moves APOLLO from millimeter range precision to millimeter accuracy.