Vice President Mike Pence announced Thursday that the Pentagon has begun planning to create a Space Force, embarking on an effort to create the first new armed service since 1947.

In June, President Donald Trump called for the establishment of the sixth armed service, to join the Air Force, Army, Marine Corps, Navy and Coast Guard.

Thursday’s plan, which requires authorization and funding from Congress, would develop forces to defend satellites from attack and other space-related tasks.

China and Russia are the nation’s primary rivals in space.

“The time has come to establish the United States Space Force,” Pence said.

The force would be created by 2020, Pence said. Before that, the Pentagon will create the US Space Command, which will be led by a four-star officer and draw forces from the other armed services.

When the proposal for a separate force was launched last year, Defense Secretary Jim Mattis resisted it.

He wrote to Congress that it would “likely present a narrower and even parochial approach to space operations.”

But Mattis signaled earlier this week that establishing a combatant command was a possibility.

“We need to address space as a developing war fighting domain and a combatant command is certainly one thing that we can — we can establish,” Mattis told reporters.

“This is a process we’re in. We are in complete alignment with the president’s concern about protecting our assets in space that contribute to our security, to our economy. And we’re going to have to address it as other countries show a capability to attack those assets.”