"We have to be prepared," Trump told reporters after signing the directive.

"My administration has made the creation of a space force a national security issue."

Last year, Trump said he wanted to create a Space Force to protect satellites, tackle vulnerabilities in space and assert US dominance in orbit.

It would be the sixth branch of the military alongside the Navy, Marine Corps, Army, Air Force and Coast Guard.

The order calls for Congress to draft legislation that would establish the Space Force as a branch that falls under the Air Force, similar to how the Navy oversees the Marine Corps.

The Pentagon did not immediately comment on the matter.

The creation of a Space Force is not a done deal, as it must be vetted and approved by Congress. Lawmakers and defense officials have reacted with skepticism, wary of the cost and added bureaucracy.

Space plays a vital role in just about every aspect of modern warfare, with many military technologies reliant on a network of orbiting sensors and satellites, and the Pentagon has warned that countries like Russia and China are working to build anti-satellite capabilities.