Attachment A3-Topic 3 -Statement of Objectives.pdf

Attachment A3: Statement of Objectives (SOO) Topic 3 NextSTEP-3 Appendix A

1. PURPOSE

This Statement of Objectives (SOO) defines mission need, objectives, desired outcomes, and constraints to enable industry to propose commercially viable and credible solutions to Topic 3 of NextSTEP-3 Appendix A.

Offerors are expected to apply independent scientific and engineering judgment in selecting technical approaches and proposed solutions that best satisfy the objectives and outcomes defined herein.

See Appendix A for additional solicitation details.

2. BACKGROUND/MISSION NEED

NASA seeks higher conversion efficiency Radioisotope Power System (RPS) technologies that are reliable, robust, and capable of long operational lifetimes to support future exploration missions to the Moon, Mars, and the outer planets. Higher-efficiency power conversion systems, such as Radioisotope Stirling Generators (RSGs), can reduce the amount of required fuel by a factor of three to four compared to current RPS technologies while also enabling the potential use of alternative fuels. Advancing RSG technology to higher technology readiness levels is critical for reducing engineering risk and developing scalable power system architectures that can operate in dark, dusty, and extreme environments across the solar system.

The effort is fundamentally a research and development initiative aimed at refining system designs and demonstrating innovative approaches where full system definitions are still evolving. NASA will lead this effort’s development of system designs for potential future adoption into a nuclear-fueled mission. Future nuclear missions could potentially be regulated by the Nuclear Regulatory Commission (NRC) and Federal Aviation Administration (FAA) for non-plutonium fueled systems. The NRC and FAA are collaborating on safety, security, and licensing for space-based nuclear systems and security overflights. The FAA licenses space nuclear launches, while the NRC sets radiological safety standards, with recent guidance focused on licensing, hazard analysis, and radiological safety for space vehicles.

3. OBJECTIVES

The overall objective of this effort is to design a high-efficiency Radioisotope Stirling Generator (RSG) and fabricate and test an electrically heated prototype for lunar applications. An RSG includes subsystems: Stirling power convertor(s), electronic controller, thermal management, heat source, and potentially dynamic balancer. However, proposals should consider designs with extensibility for survival in the Mars environment, higher levels of power output, longer life to support Moon to Mars objectives, and the use of isotope fuel listed in section 5. Extensibility can be demonstrated analytically but shall not be explored in hardware. Additional designs or design evolution may be needed to meet extensibility which should be discussed if true. Extensibility to higher power levels can be achieved through a single system design or by integrating multiple redundant systems.

Successful efforts shall address the following key objectives:

3.1 Objective 1 – System Design: Produce a system design of a high-efficiency RSG capable of supporting future missions to the Moon and Mars, providing necessary survival heat and power for landers and rovers to endure harsh environments (e.g., permanently shadowed regions and extended lunar nights). It does not include development for integration with another power generator or distribution system. Designs should provide 40-50% of full power output upon a single failure, which can be accomplished by using multiple convertors in a single generator or by using multiple generators configured on a spacecraft.

3.2 Objective 2 – Prototype Fabrication & Testing: Demonstrate advancement of RSG technologies from a starting Technology Readiness Level (TRL) of 3–4 to a target TRL of 5– 6 through subsystem and system-level demonstrations in relevant ground environments. It is required that technologies start at a TRL of 3-4 and proposals should include evidence such as description of functionality, analysis, and test results to support TRL claims for the proposed subsystem designs. A NASA-led Technology Readiness Assessment (TRA) for the system and each subsystem (except for the heat source) will be completed to verify TRL 5-6.

This objective includes demonstrating an electrically heated prototype operating with a simulated spacecraft bus in relevant environments to validate integrated system performance (efficiency, fault tolerance, monitoring, and control). Electrically heated heat source designs should include physical characteristics (heat flux, temperature capability, geometry, and mass) of a representative nuclear heat source design to enable demonstration of key thermal and structural interfaces needed in the generator design. This effort does not include radiological or aeroshell safety analysis/test for heat source maturation.

3.3 Objective 3 – Interface Maturation & Extensibility: Mature interfaces for delivering rejected heat to key spacecraft locations and document extensibility to higher power levels and longer life. The heat rejection hardware shall be integral to the RSG design to enable demonstration of heat transfer to a notional host spacecraft. The heat rejection hardware may not always be pulling heat by a host spacecraft during application or during qualification testing, prior to integration.

3.4 Objective 4 – Regulatory Pathways: Develop draft regulatory processes and schedules, including identifying major milestones and risks for the selected fuel type. Early engagement with the appropriate authorities is required to meet regulatory standards and launch authorization for a RSG. The goal is to inform what needs to be done, how long it will take, and what risks exist for a potential follow-on effort.

4. PERFORMANCE OUTCOMES

Successful efforts shall achieve the following outcomes and defined Key Performance Parameters (KPPs) that are targets with some flexibility, to be negotiated within the system requirements document:

4.1 Demonstration of an RSG design capable of providing 50-150 We DC power output (KPP), extensible to approximately 300 We (KPP), and designed exclusively for a vacuum environment (KPP). The 50-150 We DC power output shall be demonstrated in hardware while extensibility can be demonstrated analytically. Additional designs or design evolution may be needed to achieve higher power designs, which should be discussed if true but not explored in hardware.

4.2 Validation of integrated system performance achieving at least 20% system efficiency (KPP), a specific power of at least 1 W/kg (KPP), and a minimum design life of 5 years, with extensibility to 10 years (KPP). The 1 W/kg does not include the thermal management hardware to transfer heat to the host but includes the generator heat rejection hardware to radiate heat to the environment and all other generator subsystems.

4.3 Demonstration of 40-50% of available heat rejected from the RSG is made available to the host spacecraft (KPP), even in the event of a single failure.

4.4 Functional demonstration of technologies using subsystems to reduce risk, alongside validation of a Technology Development Plan that reduces risk for key interfaces.

4.5 Successful operation of an electrically heated RSG on a simulated spacecraft bus in relevant environments, characterizing performance during simulated environments based on lunar mission concept of operations and fault scenarios.

4.6 Delivery of a Draft Report of Regulatory Processes and schedule that defines met safety criteria, fuel production, regulation, and integration informed by regulatory bodies for a selected fuel type. Any fuel type that meets the design life is acceptable (KPP).

5. CONSTRAINTS AND SCOPE

The following in-scope and out-of-scope constraints apply to all proposed technical approaches.

Offerors shall ensure their proposed technical approach strictly adheres to these boundaries.

5.1 In-Scope: The following elements shall be considered in scope and included in this effort:

5.1.1 Fuel Options: Heat source designs that utilize Americium 241 fuel and show potential extensibility to other radioisotopes while supporting the required KPPs.

5.2 Out-of-Scope: The following elements shall be considered out of scope and are excluded from this effort:

5.2.1 Extraneous Fabrication: Fabrication of costly subsystems and/or systems not directly supporting the required prototype demonstration.

5.2.2 Flight Hardware: Flight hardware procurement suitable for the qualification of flight designs.

5.2.3 Destructive Testing: Destructive inspection of the system hardware.

6. DELIVERABLES, MILESTONES AND REVIEWS

Offerors shall propose deliverables, milestones and reviews appropriate to the maturity, scope, and technical approach of their proposed efforts. Proposed milestones shall represent meaningful and measurable technical progress. Proposed deliverables shall provide sufficient objective technical evidence to demonstrate progress toward, or achievement of, the stated objectives and outcomes. Proposed reviews and Government insight activities shall provide the Government with opportunities to assess technical progress, performance, technical maturity, and readiness to proceed. The desired deliverables, milestones, and reviews of a successful proposal include:

6.1 Design reviews include systems requirements, conceptual design, preliminary design, critical design, and test readiness. Associated review artifacts, data packages, and supporting documentation shall be provided in formats and with content mutually agreed upon during review planning with NASA.

6.2 Delivery to NASA of RSG hardware including prototype components, sub-systems, or integrated electrically heated system demonstration articles representative of the proposed system design. The RSG shall be delivered in the configuration and state in which testing was completed to achieve TRL 5-6. NASA will take ownership of the delivered RSG hardware.

6.3 Technical reports consisting of system design description, concept of operations, as-built drawings, interface control document, assembly and integration, verification and validation plan, test procedures, risk reduction for critical technology elements and key interfaces, lunar mission concept of operations and fault scenarios, technology and manufacturing maturity, and technical progress throughout the period of performance.

6.4 Design and performance data supporting the assessment of extensibility to higher power levels including impact on key performance parameters.

6.5 Test reports documenting validation of key performance parameters and characterization of electrical, thermal, operational, functional, and environmental performance (e.g., efficiency, power output, heat rejection, flight design mass) of the RSG subsystems and systems.

6.6 Documentation describing the proposed pathway for advancing the Technology Readiness Level (TRL) of the demonstrated technology, alongside draft regulatory processes, schedules, safety criteria, and integration hurdles for a potential follow-on effort.

6.7 Government insight activities, including technical interchange meetings, monthly status reports, monthly meetings, demonstrations, and site visits, as appropriate and coordinated with the Government, to support technical assessment, collaboration and programmatic visibility throughout the period of performance. NASA will actively engage with selected Offerors through ongoing technical engagement, milestone reviews, and Government insight and oversight activities to support assessment of technical progress, and achievement of program objectives.

6.8 Final report (Limited and Unlimited versions. Unlimited versions shall be free from ITAR/EXPORT control and should be able to be shared with the public.) and presentation.

The final report and presentation shall include a summary of assembly and integration, relevant environmental test results, updated risk register for current mitigations and residual risks, evidence supporting subsystem and system TRL claims, lessons learned and recommended potential future work. Based on the TRL evidence provided, a NASA-led Technology Readiness Assessment (TRA) of the subsystems and the system will be completed.

6.9 Continuation Review: The Contractor shall support a continuation review for each CLIN prior to completion of the CLIN and, when applicable, prior to Government authorization to proceed with the subsequent CLIN. The Contractor shall provide the Government with information sufficient to assess technical performance, schedule status, risk retirement, deliverable status, unresolved issues, technical maturity, and readiness to proceed. The Contractor shall also provide its recommendation regarding continuation. The Government will use the results of the continuation review to inform its decision regarding exercise of the subsequent Option.