Donald Trump has said space will be the next “war fighting domain” as he formally launched a new military “Space Command”.

A full 17 years after the original Space Command, first established in 1985 to coordinate the various space functions of the US military, was put on ice following the attacks of 9/11, Mr Trump claimed it was more necessary than ever.

“This is a landmark day,” Mr Trump said at a ceremony in the Rose Garden of the White House. “Space Command will boldly deter aggression and outpace America’s rivals by far”.

He said Space Command, headed by a four-star Air Force general, would “ensure that America’s dominance in space is never questioned and never threatened”.

When he spoke to members of the US military at the Marine Corps Air Station Miramar in California in March 2018, the president first voiced the idea of having an actual space force.

Race to Space: US and Soviet Union's Cold War rivalry Show all 8 1 /8 Race to Space: US and Soviet Union's Cold War rivalry Race to Space: US and Soviet Union's Cold War rivalry US astronaut Alan B Shepard Jr sitting in his Freedom 7 Mercury capsule, ready for launch on 5 May 1961. Just 23 days earlier, Soviet cosmonaut Yuri Gagarin had become the first man in space. After several delays and more than four hours in the capsule, Shepard was ready to go, and he famously urged mission controllers to “fix your little problem and light this candle”. Pictures by Nasa/EPA Race to Space: US and Soviet Union's Cold War rivalry Wernher von Braun (centre) explains the Saturn rocket system to President John F Kennedy at Launch Complex 37 while the president tours the Cape Canaveral Missile Test Annex, on 16 November 1963 Nasa/EPA Race to Space: US and Soviet Union's Cold War rivalry A back-up copy of the first Russian Sputnik (satellite, right), and a small replica of the second Russian satellite displayed in a small museum in the cosmonaut training centre in Star City outside Moscow. The second satellite was launched just a month later on 3 November 1957 with dog Laika on board. EPA Race to Space: US and Soviet Union's Cold War rivalry Jet propulsion laboratory director William Pickering (left), Dr James Van Allen (centre), and Dr Wernher von Braun (right) hold up a model of the first US satellite Explorer 1, which successfully launched on 31 January 1958 Nasa/EPA Race to Space: US and Soviet Union's Cold War rivalry President Kennedy speaks to the nation at the joint session of congress, in Washington, DC, on 25 May 1961, where he said: “I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to Earth.” Nasa/EPA Race to Space: US and Soviet Union's Cold War rivalry A visitor passes in front of a picture of Yuri Gagarin, the first cosmonaut of the USSR, inside the Vostok 1 command capsule on display at the exhibition “The way of Gagarin – achievement of Russian manned cosmonautics” in Moscow. On 12 April 1961, Gagarin performed a space flight aboard the Vostok-1 spacecraft, orbiting Earth in 108 minutes and landing safely near Smelovka village in the Saratov region's Ternovsky district. EPA Race to Space: US and Soviet Union's Cold War rivalry A model of the world’s first artificial satellite, Sputnik 1, hangs in the Smithsonian National Air and Space Museum in Washington, DC EPA Race to Space: US and Soviet Union's Cold War rivalry Full length image of US astronaut Alan B Shepard Jr Nasa/EPA

“Space is a war-fighting domain, just like the land, air, and sea,” he said. “We may even have a Space Force, develop another one, Space Force. We have the Air Force, we’ll have the Space Force.”

He added: “I was not really serious. Then I said, ‘what a great idea’, maybe we’ll have to do that.”

Mr Trump repeated that point, when he officially marked the reestablishment of the US Space Command.

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“SpaceCom will soon be followed, very importantly, by the establishment of the United States Space Force as the sixth branch of the United States Armed Forces,” he said. “And that’s really something, when you think about it. The Space Force will organise, train, and equip warriors to support SpaceCom’s mission.”

The role of the new command will be to conduct space operations such as enabling satellite-based navigation and communications for troops and commanders in the field and providing warning of missile launches abroad. That is different from a Space Force, which would be a distinct military service, in the way the Army, Navy, Air Force, Marine Corps and Coast Guard are distinct services, the Associated Press said.

It said Congress had inched towards approving the creation of a Space Force despite scepticism from some members of both parties.

The House and Senate bills differ on some points, and an effort to reconcile the two will begin after Congress returns from its August recess.

When Jim Mattis was defence secretary, the Pentagon was hesitant to embrace the idea of a Space Force. Mr Trump’s first Pentagon chief initially saw it as potentially redundant and not the best use of money.

By contrast, his successor, Mark Esper, has cast himself as a strong supporter of creating both a Space Force and a command dedicated to space.

“To ensure the protection of America’s interests in space, we must apply the necessary focus, energy and resources to the task, and that is exactly what Space Command will do,” Mr Esper told reporters this week.

“As a unified combatant command, the United States Space Command is the next crucial step towards the creation of an independent Space Force as an additional armed service.”

Some criticised Mr Trump’s announcement.

“Trump again called space a “war-fighting domain” and that’s reckless from a security standpoint and could waste billions of taxpayer money,” said Jon Rainwater, executive director of the non-profit organisation Peace Action. “Given that any fighting in space would likely be with nuclear powers like Russia and China, the militarisation of space adds to the risk of nuclear war.”

He added: “At a time when Trump is abandoning arms control agreements and sparking a new nuclear arms race we don’t need to add to the nuclear threat.”