The US has outlined plans to "prepare for the next battlefield" by creating a new "Space Force" to counter the threat of China and Russia.
Envisaged as the sixth branch of the American military, the White House wants the Space Force to be created by 2020, the end of Donald Trump's term in office.
The US president marked Thursday's announcement of details of the plans by exclaiming on Twitter: "Space Force all the way!"
Speaking to an audience at the Pentagon, as he set out more details about the proposal, vice-president Mike Pence said: "The time has come to write the next great chapter in the history of our armed forces.
"To prepare for the next battlefield where America's best and bravest will be called to deter and defeat a new generation of threats to our people, to our nation.
"The time has come to establish the United States Space Force."
Mr Pence cited the threat of China and Russia as a basis for establishing the new military branch, claiming both Beijing and Moscow are "aggressively" developing anti-satellite capabilities.
He said the countries "have been conducting highly sophisticated on-orbit activities that could enable them to manoeuvre their satellites into close proximity of ours, posing unprecedented new dangers to our space systems".
The current branches of the US military are the Navy, Coast Guard, Marine Corps, Army and Air Force.
Space warfare capabilities are currently overseen by the US Air Force.
Mr Trump ordered defence officials in June to "immediately" begin work on establishing the new sixth force.
Mr Trump "knows that space is integral to our American way of life and economic prosperity and is a vital domain for national defence" while, under his direction, the US is "reclaiming its heritage as the world's greatest space-faring nation", the White House said.
The steps towards establishing a Space Force are creating a Space Development Agency, a Space Operations Force and a United States Space Command, the White House added.
In March this year, Mr Trump's National Space Strategy was said to recognise US "competitors and adversaries have turned space into a warfighting domain".
US defence secretary James Mattis has previously been against establishing a new military branch specifically for space.
But, earlier this week, Mr Mattis said he is in "complete alignment" with Mr Trump's concerns about US space assets.
Responding to Thursday's outlining of plans for a Space Force, Democrats were withering about Mr Trump's ambitions.
David Cicilline, who sits in the House of Representatives, asked if "no Republican" would tell the president "what a dumb idea Space Force is".
"This is so stupid," he added.
Hawaii senator Brian Schatz branded the Space Force a "silly but dangerous idea" as he instead urged the expansion of the "Medicaid" health programme.
Mr Trump's plans for a Space Force require approval by Congress, with a budget for the scheme to be outlined next year.
The Republicans face a battle to hang on to control of the Senate and House of Representatives in November's mid-term elections.