NASA Administrator Jim Bridenstine, center, is seen on a work platform between the four RS-25 engines of the first core stage of the agencyâs Space Launch System (SLS) rocket along with Lisa Bates, SLS Deputy Stages Manager at NASA, Mark Nappi, Boeing Green Run Test Manager, Richard Gilbrech, Director of NASA's Stennis Space Center, Julie Bassler, SLS Stages Manager at NASA, and NASA astronaut Raja Chari, during a tour of the B-2 Test Stand, Monday, Feb. 10, 2020, at NASA's Stennis Space Center near Bay St. Louis, Mississippi. Over the coming months, the first core stage of NASA's SLS rocket will be undergoing a series of integrated Green Run tests prior to its maiden flight. Photo Credit: (NASA/Joel Kowsky)