With a signature tonight, President Trump created a sixth military service — the U.S. Space Force — the first new service since the Air Force was established in 1947. Two years after a bipartisan duo on the House Armed Services Committee (HASC) began a campaign to reorganize DOD to raise the visibility of and attention to space activities as a critical element of U.S. military power, it is finally a reality.

In a ceremony at Joint Base Andrews in the Washington D.C. suburbs, Trump signed into law the FY2020 National Defense Authorization Act (NDAA), which creates the Space Force or USSF. It is part of the Department of the Air Force, similar to the Marine Corps, which is part of the Department of the Navy.

With that signature, the Air Force Space Command (AFSPC) ceased to exist. It is now the USSF and AFSPC’s commander, Gen. John “Jay” Raymond, is now Chief of Space Operations, in command of USSF and reporting to the Secretary of the Air Force (SecAF). Raymond is dual-hatted as Commander of U.S. Space Command, a unified combatant command.

According to the NDAA, the Space Force consists of members of the Air Force as assigned by the SecAF. SecAF Barbara Barrett today assigned all airmen in Air Force Space Command to USSF.

In a press briefing earlier today, she estimated the USSF now is comprised of 16,000 active duty Air Force and civilian personnel. Asked about the timeline for futher action, Raymond said there are “thousands and thousands of actions” that need to take place from what the uniforms will look like to who is in or not in the Space Force.

The Space Force and Space Command are two different organizations, even though at the moment Raymond commands both.

Pursuant to the 1986 Goldwater-Nichols Act, the military services organize, train and equip (OTE) personnel. As of today there are six military services: Army, Navy, Marine Corps, Air Force, Space Force, and Coast Guard.

The 11 unified combatant commands, of which U.S. Space Command is one, provide command and control of military forces in peace and war, drawing resources from across the military services. A U.S. Space Command existed from 1985-2002, but was eliminated in a reorganization of the unified commands after the September 11, 2001 terrorist attacks. President Trump reestablished it in August, which did not require congressional action.

Creating a new military service does require authorization from Congress. Two years ago, Rep. Mike Rogers (R-AL) and Rep. Jim Cooper (D-TN), the chairman and ranking member of the Strategic Forces subcommittee of the House Armed Services Committee (HASC) proposed creation of a Space “Corps” as part of the Air Force. That was approved by the House, but rejected by the Senate. The journey from then until now has been tumultuous, shaped in part by Trump’s enthusiasm and insistence that DOD embrace the idea of a Space “Force.” In the end, what Congress approved in the FY2020 NDAA and became law tonight is quite similar to what they had in mind even though it bears the name Space Force instead of Space Corps.

Congress is taking a cautious approach to Space Force and imposed a number of limitations in the NDAA. Appropriators approved only $40 million of the $72.4 million request to stand up Space Force. That does not include funding for space programs, which is about $14 billion not including classified programs. The NDAA allows 18 months for all the pieces of USSF to fall into place.

Secretary of Defense Mark Esper issued a memoradum today saying he expects all DOD components to fully support “this historic reorganization of DoD space forces.”

The NDAA also calls for changing the acquisition process for space systems, a perennial complaint. It also elevates the position of Deputy Assistant Secretary of Defense for Space Policy to an Assistant Secretary level.

This article has been updated.