It all began when Bridenstine put out a statement on Twitter ahead of Musk's big reveal of his new Starship rocket prototype Saturday, saying NASA “expects to see the same level of enthusiasm focused on the investments of the American taxpayer” as the Commercial Crew – a project which involves SpaceX and Boeing developing spacecraft that can ferry astronauts from US soil to the International Space Station and which is, according to Bridenstine, years behind schedule.
Musk addressed the NASA head's words during his Starship update from Texas Saturday, saying, "From a SpaceX resource standpoint, our resources are overwhelmingly on Falcon and Dragon […] It was really quite a small percentage of SpaceX that did Starship."
Musk had hoped to send the first astronauts to the International Space Station in a Crew Dragon earlier this year, but a testing mishap on the ground led to the explosion of a Crew Dragon unit and set back that timeline.
Yet, offstage, Musk couldn’t resist letting himself loose in an interview with CNN, responding to Bridenstine's tweet with a question: “Did he say Commercial Crew or SLS?”
“Jim Bridenstine said, quote, Commercial Crew is years behind schedule & it’s time to deliver. Did you take that ...”— Viv (@flcnhvy) September 29, 2019
“Did he say Commercial Crew or SLS?”
This is it. The finest burn in history. @elonmusk 😀 pic.twitter.com/lvlnzvIXbt
Musk was referring to NASA's next-generation Space Launch System, which is over budget and years overdue. Earlier reports, which were not confirmed by NASA, even suggested that SLS is to be cancelled and that the agency is considering the possibility of contracting with SpaceX for future SLS launches, like the planned Artemis mission to return to the Moon.
"Everything in aerospace is years behind, OK?" Musk went on to say. "Relatively speaking, which one is more late ... we're really going as fast as we can make it go."