A picture of Earth from space (Picture: UK Space Agency).
US President Donald Trump has formally established a new Pentagon command for space warfare.
SpaceCom will oversee US military and intelligence efforts in space, including defending American satellites and supporting troops.
Speaking at the White House, President Trump said Space Command will defend America's vital interests in space and "ensure that America's dominance in space is never questioned and never threatened".
"This is a landmark day," the President said in a White House ceremony, "one that recognises the centrality of space to America's national security and defence."
The role of Space Command is to conduct operations, such as enabling satellite-based navigation and communications in the field and providing warning of missile launches abroad.
Four-star US Air Force General John "Jay" Raymond will serve as its first commander.
Watch: is the British military ready to fight in space?
The renewed focus on space as a military domain reflects concern about the vulnerability of US satellites, both military and commercial, that are critical to US interests and are potentially susceptible to disruption by Chinese and Russian anti-satellite weapons.
But Congress is yet to approve a Space Force, which would be a distinct military service like the army, navy, air force, marines and coastguard.