ORLANDO, Fla. — The U.S. military has long relied on large, expensive satellites parked in fixed orbits above the Earth. Some U.S. Space Force leaders believe it’s time to change that model in favor of more mobile and renewable satellites that can maneuver to avoid attack. “We’ve got to be better at dynamic space operations,” said Lt. Gen. Michael Guetlein, who runs the Space Force’s Space Systems Command and was nominated to be the next vice chief of the U.S. Space Force. Speaking Dec. 13 at the Space Force Association’s Spacepower conference, Guetlein said the strategic competition with China in…