The SPARC tokamak is currently under design as a mid-sized, DT burning magnetic confinement experiment. By employing novel high-temperature superconducting magnets, it will achieve 12.2 T, 8.7 MA in a modest-sized device with R = 1.85 m and a = 0.57 m. The SPARC physics mission is to create and confine a plasma that produces net fusion power and retire risks on the high-field path to commercial fusion energy. The performance to satisfy that mission has been defined as Q > 2 and PFusion > 50 MW which would be comfortably more than the 25 MW of ICRF input power. Achieving this goal, we believe, would be a sufficient demonstration to place fusion firmly into the world’s energy plans. Significant margin against uncertainties in performance assumptions has been built into the design such that well-established physics predicts that SPARC could produce more than 140 MW of fusion power with Q > 10. Successful operation of SPARC would inform and enable the construction of an ARC-class fusion pilot plant – a device with a major radius on the order of 3 m, producing over 500 MW of fusion power.