Tech billionaire Elon Musk will make a return to officially advising US President Donald Trump’s government by co-leading what the Pentagon called a study on the future of war.Musk served as the head of the Department of Government Efficiency before departing in May last year, having publicly fallen out with Trump.In a speech at the Quantico military base, Pentagon chief Pete Hegseth said “Project Meridian” will be “an effort led by America’s best minds to study the future of warfare”.“We are leveraging a unique source of American advantage, one our adversaries do not have: our innovators, our senior leaders and our technologists,” Hegseth said.