US President Donald Trump has launched a new Pentagon command focused on warfare in space.
It comes as US military chiefs see China and Russia making advancements in the military final frontier.
The command will focus on defending American interests in space, such as the hundreds of satellites used for communication and surveillance.
"SpaceCom will ensure that America's dominance in space is never threatened," Mr Trump said.
"This is a landmark day, one that recognizes the centrality of space to America's security and defence," he said.
Although there is already an Air Force focused on space warfare, the new command will be developing specialised systems and preparation for "Star Wars"-type showdowns.
Air Force General John Raymond, who will lead the new command, said US adversaries are seeking to develop their military capabilities in space.
"I'm convinced that space is a war-fighting domain. I'm convinced that our way of life and our way of war depend on space capabilities," he said.
China has illustrated it can target satellites with missiles and Russia has stated that it aims to create space-based laser weaponry.
The command is technically being reactivated after initially running from 1985 to 2002. It was ended after the 9/11 terror attacks in New York resulted in military focus shifting to homeland defence and counter-terrorism.
China, Russia and the US have all tested weapons that are capable of taking out a satellite, according to research by the Secure World Foundation, which records military capabilities in space.