Trump has mentioned the formation of a Space Force before, saying in March "space is a warfighting domain just like the land, air and sea." He admitted at the time that he initially floated the idea as a joke and then thought "what a great idea."

Congress took steps towards forming such a branch last year, but the idea was ultimately shot down. The House of Representatives included a "Space Corps" proposal in its version of the National Defense Authorization Act with the idea that it would sit within the Air Force much like the Marine Corps is housed within the Navy. However, many opposed the plan and it didn't make it into the final version of the bill. Both the Pentagon and the White House were among those against it and in October, Secretary of Defense James Mattis wrote letters to the House and Senate Armed Services Committees saying as much. "I oppose the creation of a new military service and additional organizational layers at a time when we are focused on reducing overhead and integrating joint warfighting functions," wrote Mattis.

If formed, a Space Force would join the Navy, Air Force, Marine Corps, Army and Coast Guard as a branch of the military. The Air Force currently has a Space Command division that oversees space-based military operations.

"We are going to have the Air Force and we're going to have the Space Force, separate but equal," Trump said today. "It is going to be something, so important."