WASHINGTON — Starting as early as next week, Pentagon officials will sit down with members of Congress and staff to go over the details of how the Pentagon would organize the U.S. Space Force within the Department of the Air Force

To turn President Trump’s Space Force idea into reality, the Pentagon will need strong bipartisan support from both chambers. Officials from the Office of the Secretary of Defense have been working on a messaging strategy as they prepare to present the Space Force blueprint to lawmakers. The outreach plan is viewed as crucial to secure congressional authorization to stand up the new military service in fiscal year 2020, DoD sources said, noting that there are still internal disagreements over how the Space Force proposal should be communicated to Congress and the public.

Outside of the armed services committees, many lawmakers only have a basic familiarity with the space reorganization debate. Some lawmakers have hinted that they would support the new branch but cautioned that they need to see more details before they make up their minds. It will be up to DoD and Air Force leaders to provide those details and win over skeptics. There is also still some confusion about what DoD is doing exactly. Among the questions that are likely to be asked is why the Pentagon is standing up both a U.S. Space Command and a U.S. Space Force. One is a combatant command that would be responsible for space war-fighting duties such as defending military satellites from physical or cyber attacks. The other is the military service that organizes, trains and equips forces to support U.S. Space Command operations.

A blueprint for the establishment of a Space Force already has been drafted by the Defense Department in coordination with the White House. The proposal was written in legislative language that Congress would be asked to include in the National Defense Authorization Act for Fiscal Year 2020.

One of the frequent gripes heard from lawmakers is that they have yet to see the full cost of the Space Force. According to a draft of the legislative proposal reviewed by SpaceNews, DoD would request $72 million in fiscal year 2020 to stand up the service headquarters — a number slightly higher than the $64 million proposed in a December memo from the Pentagon’s cost accounting office. Those numbers are modest compared to other much higher estimates that have been floated.

A White House official who briefed reporters this week said the Pentagon will request funds in its 2020 budget for the Space Force headquarters but most of the people and resources for the new service will be transferred from within the DoD. The Space Force budget, however, could increase in the future due to mission demands, he said. “So if we take more aggressive actions for building up resiliency of our systems, creating counter-space capabilities to counter adversary threats, those things will cost more money.”

But lawmakers are going to want to see more precise estimates for the full cost of the Space Force. Saying that the service will be “lean” might not be enough to convince undecided lawmakers. Even the White House admits that future costs could fluctuate. “As we start to stand up this function, we’re going to continue to learn more and to figure out the best way to implement the force,” the official said. “So that cost will evolve over time. It could go up, it could go down.”

The Pentagon has been emphatic that most of the Space Force funding will come from existing DoD accounts, primarily from the Air Force that today manages most military space programs. The legislative proposal would seek special authorities for the secretary of defense to transfer people and programs from other services to the Space Force.

A senior defense official speaking on condition of anonymity said there are still pieces of the Space Force puzzle that are missing as the new branch has not been fully “scoped out.” He noted that the Pentagon has had to scramble to put this together in just eight months after President Trump issued the order to create a Space Force in June 2018. It has been more than seven decades since the United States created a new military branch when it stood up the U.S. Air Force in 1947.

“Now we are in the detailed planning,” Air Force Chief of Staff Gen. David Goldfein said on Tuesday at the Brookings Institution. “There are a thousand decisions that have to be made to work in the intricate details of how we move forward” to create a Space Force within the Air Force.

Another hurdle for DoD will be the charged political climate. As much as the administration has insisted that the Space Force is a national security priority, it has been politicized by the president, observers point out, and will become even more so leading into a presidential election year. This puts more of the burden on DoD officials to persuade lawmakers to view the Space Force proposal through a non-political lens.

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...