Donald Trump has officially launched the US Space Force – the country’s first new military service in more than 70 years. 

In signing the 2020 National Defence Authorisation Act that includes Space Force, the US president claimed a victory for one of his top national security priorities just two days after being impeached.

It is part of a 1.4 trillion dollar (£1.05 trillion) government spending package — including the Pentagon’s budget — that provides a steady stream of financing for Trump’s US-Mexico border fence and reverses unpopular automatic spending cuts to defence and domestic programs.

Speaking at a signing ceremony at Joint Base Andrews just outside Washington, 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 has become increasingly important to the US economy and to everyday life – for example the Global Positioning System (GPS) which helps both the military and civilians navigate.

In a report last February, the Pentagon asserted that China and Russia have embarked on major efforts to develop technologies that could allow them to disrupt or destroy American and allied satellites in a crisis or conflict.

“The United States faces serious and growing challenges to its freedom to operate in space,” the report said.

When he publicly directed the Pentagon in June 2018 to begin working toward a Space Force, Trump spoke of the military space mission as part of a broader vision of achieving American dominance in space.

Instead of being its own military department, like the Navy, Army and Air Force, the Space Force will be administered by the Secretary of the Air Force.

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 organisation established earlier this year as the overseer of the military’s space operations.

However, Space Force will be tiny compared to its sister services.

It will initially have about 200 people and a first-year budget of 40 million dollars (£30 million).

The military’s largest service, the Army, has about 480,000 active-duty soldiers and a budget of about 181 billion dollars (£140 billion).