Presolicitation DEPT OF DEFENSE DEPT OF THE NAVY is seeking Submarine Professional Support Services in Alexandria, VA. This contract modification will provide subject matter expertise, advisory assistance, program management support activities, and nuclear-powered submarine platform engineering, technical and construction support and analysis. The contract will support foreign military sales (FMS) customers and United States (US) requirements. The period of performance will be extended through Fiscal Year 2029. This is a sole source contract and no other supplies or services will satisfy agency requirements. Interested parties should contact Systems Planning and Analysis, Inc. (SPA) directly for subcontracting opportunities. No solicitation documents are available at this time.