A preface to the draft legislative proposal says this “represents an initial effort to statutorily establish a United States Space Force as a 6th Armed Force within the Department of the Air Force.”

WASHINGTON — The Pentagon is finalizing a proposal for the establishment of a United States Space Force as a sixth military branch. According to a draft of the proposal, the Space Force would be organized under the Department of the Air Force. The Space Force would be made in the same mold as the Marine Corps, which is an independent service that resides under the Department of the Navy.

The contents of the draft proposal were first reported on Thursday by Defense News. SpaceNews reviewed a draft document that confirms what Defense News reported.

The proposal is labeled “Preliminary Draft for Policy Discussion.” A White House source confirmed that the National Space Council has been in coordination with DoD on the legislative proposal.

Vice President Mike Pence was briefed on the proposal on Thursday at the Pentagon. Deputy Defense Secretary Patrick Shanahan told reporters on Dec. 13 that the document is still being reviewed before it goes to the White House for approval. Col. Joe Buccino, a spokesman for Shanahan, said he could not comment on a draft document. “As he said last week, Deputy Secretary Shanahan is moving forward with the legislative proposal in concert with presidential guidance,” Buccino told SpaceNews.

A preface to the draft legislative proposal says this “represents an initial effort to statutorily establish a United States Space Force as a 6th Armed Force within the Department of the Air Force.” It notes that the draft is meant to inform the policy discussion and that there are still a “substantial set of conforming amendments” and provisions of law that will have to be added.

With regard to the mission and purpose of the Space Force, the proposal says the new branch “shall be organized, trained, and equipped to provide for freedom of operations in, from, and to the space domain for the United States and its allies; to provide independent military options for joint and national leadership; and to enable the lethality and effectiveness of the joint force.”

A civilian Undersecretary of the Air Force for Space would report to the Secretary of the Air Force. Like the other branches of the military, the Space Force would have a four-star Chief of Staff who would be a member of the Joint Chiefs of Staff. The Space Force would have active-duty, Reserve and National Guard components. Military personnel transferred to the Space Force from another service would retain the same grade and rank.

The Space Staff would include a Chief of Staff of the Space Force, a Vice Chief of Staff and a Judge Advocate of the Space Force. The Chief of Staff would be appointed by the President and require Senate confirmation. The Chief of Staff of the Space Force, like the Chief of Staff of the Air Force, would work under the authority, direction, and control of the Secretary of the Air Force.

The proposal does not specify the size or the estimated cost of a Space Force. It recommends allowing 180 days for the Secretary of Defense to submit to the congressional defense committees a report describing the number of civilian employees and military personnel that would be needed to support the headquarters of the the Space Force Staff, U.S. Space Command and the Space Development Agency.

Experts have argued that organizing the Space Force under the Department of the Air Force is a sound approach that meets the president’s directive to stand up a new branch and keeps overhead costs down. A similar structure was put forth by the House Armed Services Committee in a “Space Corps” provision in the National Defense Authorization Act for Fiscal Year 2018. The proposal was opposed by the Air Force and voted down by the Senate.

A Space Force as it is being proposed now would meet the criteria to be considered a sixth service, said Thomas Taverney, a retired Air Force major general who served as vice commander of Air Force Space Command. “The most important thing is to have a command structure that goes to bed at night and wakes up in the morning thinking only about the space mission and worrying only about the space mission,” Taverney said. “A Space Force equivalent to the Marine Corps would meet that criteria.”