President Trump announced on Thursday the official creation of the United States Space Command — the U.S. military’s 11th war-fighting geographic combatant command.

“The establishment of the 11th combatant command is a landmark moment. This is a landmark day. One that recognizes the centrality of space to America’s national security and defense,” Trump said in a Rose Garden ceremony.

“Spacecom will soon be followed very importantly by the establishment of the United States Space Force as the sixth branch of the United States Armed Forces, and that’s really something if you think about it,” he added.

The ceremony marked a major milestone in one of the administration’s top national security priorities, to renew American interest and investment in outer space.

Senate Armed Services Committee Chairman Jim Inhofe (R-OK) praised the official establishment of Spacecom.

“I applaud President Trump for standing up United States Space Command as a Unified Combatant Command today,” he said in a statement, which continued:

This is an important step to support the space warfighting domain and ensures our strategic competitors, Russia and China, realize we are serious about implementing our National Defense Strategy. The next step is establishing the United States Space Force, which we are working on as part of the final National Defense Authorization Act.

Rep. Mike Waltz (R-FL), a member of the House Armed Services and the Science, Space and Technology Committees, said in a statement: “I’m grateful to President Trump and his Administration for making a unified, combatant Space Command a reality and I’m also looking forward to the authorization of a new military branch to protect American assets in space.”

Air Force Gen. John Raymond, the new U.S. Space Command commander, warned during an earlier press conference that the U.S.’s edge in space was diminishing:

We’re the best in the world in space, but our level of superiority is diminishing. The scope, scale, and complexity of the threat to our space capabilities is real and it is concerning. We no longer have the luxury of operating in a peaceful benign domain and we no longer have the luxury of treating space superiority as a given. Our adversaries have had a front row seat in our many successes of integrating space, and they don’t like what they see, because it provides us with such a great advantage and they’re developing capabilities to negate our access to space. It’s an imperative that we stand up this command today.

He named China and Russia as countries that pose the more “significant threats” in space, in terms of being able to jam or target U.S. satellites.

“China and Russia in particular are updating their organization, in fact they had reform in 2015 where they’ve created a greater focus on space and they are updating their doctrine and their capabilities both space to enable to their terrestrial forces, and counterspace,” said Defense Assistant Secretary of Defense Steve Kitay, adding:

Their doctrine, and there’s a perception that space represents an achilles heel and that this is a way an asymmetric advantage for them to then take on the United States’ power because we project power globally through space-enabled capabilities…space will not become an achilles heel. We will protect and defend it and provide it for our way of life and our way of war.

Raymond said the hope is not to fight a war in space, but to prevent one.

“Although space is a war-fighting domain, our goal is to actually deter a conflict from extending into space. The best way I know how to do that is to be prepared to fight and win if deterrence were to fail,” he said.

“We have the best in the world at space today and we are even better as we establish a new United States Space Command with a singular focus on the space domain,” he said.

The Space Command will have 287 headquarters staff, and Army, Air Force, Navy, Marine components. There will be two operational components — the Combined Force Space Component Command focused on integrating space capabilities around the globe, and the Joint Task Force for Space Defense focused on protecting and defending the space domain.

The headquarters staff will be mostly those from the existing Joint Force Space Component Command, and those who are part of U.S. Strategic Command that are conducting the space mission. There are also five operational centers located around the world. The Air Force is looking at six candidate bases for Space Command’s headquarters.

Space Command’s total budget for FY19 was $83.8 million, with $75.6 million being shifted from other organizations. “In this fiscal year to get us started it was only an $8.2 million growth,” Raymond said.

Raymond said the new Space Command shares the same name as the one that existed from 1985 to 1992, but is designed for a different strategic environment.

Raymond said a major focus of standing up the Space Command is working with allies in space.

“We haven’t needed to have allies in space, space was a benign domain,” he said. He added the U.S. would work with Five Eyes partners, and allies like France, Germany, and Japan. “We’re stronger together.”

Kitay said the Pentagon is still working on standing up the Space Force as the sixth branch of the armed forces, by getting Congress to amend Title 10 to provide the Pentagon with the authority to establish it.

The Space Force would be created inside the Air Force, similar to how the Marine Corps is inside the Navy, he said.