The Department of Defense is creating the Space Force as an independent service within the Department of the Air Force to ensure access to, and freedom to operate in, space and to provide vital capabilities to joint and coalition forces in peacetime and across the spectrum of conflict. It has been 72 years since the United States last created a new military service, the Air Force. The other military services date back to the first years of the American nation. Because the Department of Defense does not often create military services, this is an opportune time to consider the implications of creating an independent Space Force. RAND developed an analytic approach to determine which units to bring into the Space Force. The authors asked how a transfer might affect any of the following four organizational attributes: effectiveness, efficiency, independence, and sense of identity. Then, the authors assessed a set of career fields to consider whether they would be sustainable in the Space Force. These analyses are complemented with an examination of other organizations that the Department of Defense has created to gain insights into potential challenges that the Space Force might face as it stands up and grows into its role.