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 U.S. is "reclaiming its heritage as the world's greatest space-faring nation", the White House said.
"President Trump and I are grateful to Secretary Mattis for this department's diligence in preparing this report, and our administration will soon take action to implement these recommendations, with the objective of establishing the United States Department of the Space Force by 2020", Pence told the crowd at the Pentagon.
"The United States will strengthen our security, will ensure our prosperity, and it will also carry American ideals into the boundless expanse of space", Pence said.
Any proposal to create a US Space Force would require congressional support.
· The establishment of a Space Development Agency to quickly create new space defense technologies.
What is the new US Space Force?
On Tuesday, however, Mattis expressed full support for creating a new US Space Command.
"President Trump wants a SPACE FORCE - a ground breaking endeavor for the future of America and the final frontier", read the email, signed by Brad Parscale, Trump's 2020 campaign manager. Only Congress has the authority to establish a new branch of the military-something that hasn't happened since the U.S. Air Force was founded in 1947.
There is spaceship logo surrounded with red and navy stars.
Afterwards, in an apparent sign of approval, Mr Trump tweeted: "Space Force all the way!"
"I watched this whole announcement this morning and I was impressed by the fact that Mike Pence was somehow able to make an announcement about interspace warfare boring", he joked. He's more recently said he's "in complete agreement" with Trump, though it's unclear if he's actually come around on the Space Force idea.
In June, Trump ordered the Department of Defense and the Pentagon to being the process of creating a sixth military branch known as Space Force. Instead, many have argued that the effort is best left under the Air Force's purview, as it is now. We have the Air Force, we'll have the Space Force.
But the proposed Space Force is not the United States' first foray into militarizing space.
After roasting Pence's speech beat by beat, he turned his attention to the president himself and broke out his Trump impression.
Neither Mr. Pence nor Mr. Mattis offered any details on what it would cost to stand up the Space Force, but the administration reportedly will seek about $8 billion in funding. That will be joined by a Space Development Agency that, by becoming part of the defense bureaucracy, is meant to be an antidote to bureaucracy and enable new thinking.