US Space Force Minimum Capabilities 2040 Author: Brent Ziarnick Background: In the first Space Future Workshop in March 2019, the US Space Force (USSF) described a realistic range of space futures to 2060 that encompassed futures both advantageous and disadvantageous to the US and our allies. This work and the resulting report sufficiently established cardinal points to navigate meaningfully the range of futures the US can shape to its advantage and those it needs to avoid. This was a necessary first step in defining the strategic decisions that the USSF must make to drive toward positive US space futures. Objective: While the first Space Futures Workshop provided valuable, broad strategic perspective for USSF decision making, additional work is required to inform mid- and long-term decisions on investment in systems, infrastructure, training, policy and human resources. The second Space Futures Workshop will bridge this gap, building on the range of space futures defined from the first workshop. The aim of the second Space Futures Workshop is to move identified positive scenarios back in time to ~2040 to define the range of expanded or new operational missions that USSF must consider to anticipate and support those scenarios. Methods: The Space Futures Workshop will bring together diverse stakeholders from across the government (including NASA, USSF, think tanks, and other civil and military personnel) to work on the identified goals, develop roadmaps, and generate detailed capabilities usable to inform initial capabilities documents and programs of record for the “Space Force after next” of 2040. Results and Conclusions: Since the workshop will be conducted in June, no results or conclusions have been determined. However, since the first Space Futures Workshop goals comport well with the objectives of the Interstellar Research Group (including space power, communications, system reliability/maintainability, psychology, propulsion, etc.) it will be mutually beneficial for the Space Futures Workshop to report to the Interstellar Research Group its resulting requirements to best determine how the USSF and IRG may work together in the future to advance common goals.