Traditional underwater propulsion systems, such as screw-type axial propellors, convert torque into thrust; in other words, power from an engine turns the propellers and generates force by moving the flow of water downward and behind the blade. Autonomous underwater vehicles (AUVs) are playing an ever-growing role in modern subocean operations, generating a demand for faster, more manoeuvrable designs capable of deployments of increasingly longer durations.
U.S. military researchers are asking the industry to develop enabling technologies for next-generation propulsion for crewed submarines and unmanned underwater vehicles (UUVs) that will be quieter and more efficient than ever before. Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., issued a solicitation (HR001122S0046) in August for the Advanced Propulsor, Experimental (APEX) project.
The APEX program will design, build, and test classified submarine propulsor technology. The BAA seeks full proposals for Phase 1 (Phase 1A Base, Phase 1B Option, and Phase 1C Option) and a rough order of magnitude (ROM) cost estimate for Phase 2 (Phase 2A and Phase 2B).
Performers will explore the propulsor design space of potential solutions for a submarine or unmanned underwater vehicle (UUV). Relevant areas of expertise include hydro-dynamics, hydro-acoustics, mechanical engineering, naval architecture (submarine), electro-mechanical, and other disciplines. The Design Space Exploration (DSE) process is expected to explore the design space with metrics related to efficiency, signature, mechanical design and limits, and operational considerations.
Phase 1A Base is a 12-month period in which performers are expected to quantitatively explore the APEX design space via a proposed DSE process. Proposals should describe the planned approach to trade space exploration and the design evolution process to assess multiple potential APEX designs and culminate in a conceptual design review (CoDR), which may include multiple potential designs. Proposers should describe the design process they intend to use, and the tools and techniques they plan to employ to conduct their DSE, as well as starting points, points of departure, and any candidate designs they intend to evaluate and why they are of interest in the trade space. CoDR level designs should only consider the full-scale designs.
Phase 1B Option is a 9-month period which may be exercised dependent upon performance and funding availability. In Phase 1B, performers will work toward defining a single APEX design approach based on the CoDR results, then refine the design through engineering design and analysis, and risk reduction activities. Phase 1B will include a System Requirements Review (SRR) and culminate with a preliminary design review (PDR) of the APEX design. PDR should include the selected full-scale objective design and a quarter-scale demonstration design variant intended for fabrication and testing in Phase 2. Proposers will be expected to show traceability between the objective and demonstration designs.
Through an updated BAA during Phase 1B with limited competition among Phase 1B performers, a single performer and single concept may be selected for Phase 2 of the program where a detailed design will be finalized and a quarter-scale demonstration unit will be built and tested.