This report proposes expanding the use of testbed and proving ground infrastructure to advance US space capabilities in the national interest. Addressing the testing and validation challenges for commercial capabilities to be assimilated into hybrid architectures for national security can increase mission success and accelerate the commercialization and operational readiness of US space economy and ecosystems. The authors of this report explain how this strategic approach will support the USSF objectives of space domain superiority and drive sustained growth and innovation in the broader space community.