Elon Musk's SpaceX halted Tuesday's launch of a long-delayed navigation satellite for the U.S. military, postponing for at least a day the space transportation company's first designated national security mission for the United States.

SpaceX's Falcon 9 rocket, carrying a roughly $500 million GPS satellite built by Lockheed Martin Corp., was due to take off from Florida's Cape Canaveral shortly after 9:30 a.m. local time, but was stopped minutes before takeoff.

"This abort was triggered by the onboard Falcon 9 flight computer," a SpaceX official narrating the launch sequence said. He said SpaceX would attempt the launch on Wednesday morning.