US President Donald Trump has celebrated the launch of Space Force.
It is America's first new military service in more than 70 years, and falls under the US Air Force part of the $738 billion dollar defence bill agreed by both houses in Congress.
Troops will not be put into orbit, but the new force will protect US assets, such as satellites used for communication and surveillance.
Speaking at a signing ceremony at Joint Base Andrews just outside Washington, Mr Trump said: "Space is the world's new war-fighting domain.
"Among grave threats to our national security, American superiority in space is absolutely vital. And we're leading, but we're not leading by enough, and very shortly we'll be leading by a lot."
Space Force is the first new military service since the Air Force was spun off from the Army in 1947.
It will be the provider of forces to US Space Command, a separate organization established earlier this year as the overseer of the military's space operations.
Cover image: view of the earth and a satellite from space (Picture: NASA).