SpaceX founder and chief engineer Elon Musk. REUTERS/Steve Nesius The US military's increasing need for fast transport explains why it keeps handing contracts to SpaceX, according to a leading aerospace expert. Steve Nutt, professor in aerospace engineering, told Business Insider that SpaceX is the US' best alternative to "stodgy, slow" traditional contractors. it comes at a time when the Department of Defense is "retooling" in light of growing global political tension, Nutt said. "The rockets that SpaceX has been asked to supply would address that need — delivering hardware and support supplies rapidly to anywhere in the world," Nutt said. Visit Business Insider's homepage for more stories. Elon Musk's SpaceX has secured three military contracts in as many months — and one aerospace expert believes the deals won't end there.The US Department of Defense (DoD) increasingly wants to transport supplies faster, according to Steve Nutt, professor of aerospace and mechanical engineering at the University of Southern California.SpaceX can fulfill that need at a time when the US military is "retooling" because of growing global political tensions, Nutt told Business Insider."The rockets that SpaceX has been asked to supply would address that need — delivering hardware and support supplies rapidly to anywhere in the world," Nutt said.Traditional contractors have proven to be "so stodgy, slow, and expensive that SpaceX is the only alternative," he said.In August, SpaceX won a slice of a billion-dollar agreement to launch new rockets for the Space Force.