Elon Musk’s SpaceX won its second-ever launch contract from the U.S. military by underbidding an alliance of defense industry giants.

Cost was a determining factor in awarding the $96.5 million contract to Space Exploration Technologies Corp., Claire Leon, the Air Force’s launch enterprise director, said on a conference call Wednesday. The company will launch an Air Force GPS satellite on an upgraded Falcon 9 rocket sometime in 2019.

SpaceX has added competition to military launches for United Launch Alliance, a joint venture between Boeing Co. and Lockheed Martin Corp. Musk’s Falcon 9 rocket won U.S. Air Force certification for national security space missions in May 2015, breaking a lock long held by ULA. Contracts for military launches include satellites that let troops communicate on battlefields and are estimated to be valued at about $70 billion through 2030, according to the U.S. Government Accountability Office.

With NASA, SpaceX has a $1.6 billion contract to resupply the International Space Station and a second pact valued at as much as $2.6 billion to transport crews to the orbiting lab. The closely held company expects to launch a commercial satellite early Thursday and to launch its first “flight proven” rocket--one that has been flown and recovered on land or at sea --later this month.

“SpaceX is proud to have been selected to support this important National Security Space Mission,” Gwynne Shotwell, SpaceX’s president, said in a statement. “We appreciate the confidence that the U.S. Air Force has placed in our company and we look forward to working together towards the successful launch of another GPS-III mission.”

SpaceX may bid on 13 additional launches the Air Force is preparing. The next should be awarded this summer, Leon said.