An internal Air Force document says President Donald Trump's planned creation of a Space Force could cost nearly $13 billion in its first five years.

The estimate is made in a memo written by Air Force Secretary Heather Wilson. She proposes pushing ahead with the transition to a Space Force whose main focus would be competition with Russia and China.

Creation of Space Force as a separate military service will require congressional approval.

A copy of the Sept. 14 Air Force memo was obtained by The Associated Press.

The memo says the first-year cost of a Space Force would be $3.3 billion, and the cost over five years would be an estimated $12.9 billion.