In August 2020, the U.S. Space Force awarded ULA along with SpaceX a firm, fixed-price indefinite-delivery contract to launch 60% of National Security Space Launch (NSSL) Phase 2 missions over a 5-year procurement with the next-generation Vulcan Centaur rocket. In September 2020, ULA announced that ULA is carefully studying a "Vulcan Heavy" variant with three booster cores. Speculation about a new variant had been rampant for months after an image of a model of that version popped on social media. Tory Bruno later tweeted a clearer image of the model and said it was the subject of ongoing study.