NASA 2026-2027 SBIR STTR BAA Appendix 26B-I STTR.pdf

National Aeronautics and

Space Administration

Small Business Innovation Research (SBIR) and

Small Business Technology Transfer (STTR) Programs

FY26-27 Broad Agency Announcement (BAA)

Broad Agency Announcement 80NSSC26R0003

Appendix 26B:

Small Business Technology Transfer (STTR) Phase I

Funding Opportunity

Originally Issued: April 21, 2026

Proposals Due: May 21, 2026 by 5:00 PM ET

NASA SBIR/STTR Program

FY26-27 BAA Appendix 26B-I STTR i

FY26-27 BAA- Appendix 26B: Small Business Technology Transfer (STTR)

Phase I

Change Log

Version Description of Changes Date

Original Release ----- April 21, 2026 ii

Contents

Executive Summary

Important Dates

Multiple Submissions

1. Program Description

1.13.1 Questions About This Solicitation and Means of Contacting NASA SBIR/STTR Program

2. Registrations, Certifications and Other Information

3. Proposal Preparation Instructions and Requirements

3.2 Multiple Proposal Submissions

4. Method of Selection and Evaluation Criteria

5. Considerations for Contracting and Additional Information

6. Submission of Proposals

6.1 How to Submit your Proposal Package

6.1.1 Electronic Submission of Proposals

6.1.2 Deadline for Proposal Package Submission

6.1.3 Proposal Package Submission

6.1.4 Acknowledgement of a Proposal Package Receipt

6.1.5 Withdrawal of Proposal Packages

6.1.6 Service of Protests

6.2 Phase II Information

7. Proposal, Scientific and Technical Information Sources

8. Submissions Checklist

9. Research Topics

Attachment 26B.1 STTR Phase I Evaluation Rubric

Attachment 26B.2 STTR List of Clauses, Regulations and Certifications

Executive Summary

This is the third appendix to NASA SBIR/STTR Program FY2026-2027 Broad Agency Announcement (BAA) and solicits proposals for the Small Business Technology Transfer (STTR) Phase I funding opportunity.

Chapter 6 of this appendix contains the proposal submission instructions and Chapter 9 contains the technical research topics. Instructions for how to prepare your proposal can be found in the BAA

(https://sam.gov/workspace/contract/opp/bf991b7587b1438ca7930a9b840635dc/view). The chapter numbers align to the chapters in the BAA and can be used to locate additional information within the BAA. In any instance where specific requirements in this appendix conflict with requirements in the BAA, the specific requirements in this appendix take precedence for this opportunity.

Important Dates

Proposals Due: May 21, 2026 by 5:00 PM ET

Note that the submission open period is shorter than prior years.

Deadline for guaranteed response from the Help Desk: May 20, 2026 by 5:00 PM ET

Multiple Submissions

NASA will not accept more than two (2) proposal packages from any one offeror for this funding opportunity. See sections 3.2 in this appendix and section 4 in the BAA.

https://sam.gov/workspace/contract/opp/bf991b7587b1438ca7930a9b840635dc/view

1. Program Description

1.13.1 Questions About This Solicitation and Means of Contacting NASA SBIR/STTR Program

The Help Desk will not guarantee a timely answer to questions about this appendix after May 20, 2026, at 5:00pm

ET.

2. Registrations, Certifications and Other Information

No additional content, requirements, or exceptions beyond information in BAA.

3. Proposal Preparation Instructions and Requirements

3.2 Multiple Proposal Submissions

Each proposal must be based on a unique innovation, limited in scope to just one subtopic, and submitted only under that one subtopic. You may not submit more than two (2) proposals to the funding opportunity in this appendix. You may submit more than one unique proposal to the same subtopic; however, you must not submit the same (or substantially equivalent) proposal to more than one subtopic. If you submit substantially equivalent proposals to several subtopics, NASA may decline all such proposals.

4. Method of Selection and Evaluation Criteria

The rubric containing all evaluation criteria is available in attachment 26B.1 STTR.

5. Considerations for Contracting and Additional Information

No additional content, requirements, or exceptions beyond information in BAA.

6. Submission of Proposals

6.1 How to Submit your Proposal Package

NASA uses electronically supported business processes for the SBIR/STTR program. You must have internet access and an email address. NASA will not accept paper submissions. NASA’s electronic systems for submission and contract management are not document repositories. NASA follows federal regulations for records management and disposal (NPR 1441.1E).

6.1.1 Electronic Submission of Proposals

NASA will be using ProSAMS for the submission of these proposal packages. ProSAMS requires firm registration and login. To access ProSAMS, go to https://prosams.nasa.gov/. To submit proposals to this appendix, select “STTR

2026B-I” from the solicitation type dropdown as you start a new proposal.

NASA recommends that an authorized small business representative be the person to register the firm and complete the required firm level forms. They will be the only person allowed to edit the firm level forms.

For successful submission of a complete proposal package, you must complete all required and applicable forms and upload the required documents per the submission requirements indicated in ProSAMS.

https://nodis3.gsfc.nasa.gov/displayDir.cfm?Internal_ID=N_PR_1441_001E_&page_name=Preface https://prosams.nasa.gov/

6.1.2 Deadline for Proposal Package Submission

NASA must receive your proposal package for STTR Phase I no later than 5:00 p.m. ET on Thursday, May

21, 2026, via ProSAMS.

You are responsible for ensuring that all files constituting the proposal package are uploaded and endorsed prior to the deadline. If a proposal package is not received by the 5:00 p.m. ET deadline, NASA will determine the proposal package to be incomplete and will not evaluate it. Start the submission process early to allow sufficient time to upload the complete proposal package.

If you wait to submit a proposal package near the deadline, you are at risk of not completing the required uploads and endorsements by the required deadline, and NASA may decline the proposal package.

6.1.3 Proposal Package Submission

Upload all components of a proposal package using the Proposal Submissions module in ProSAMS. The designated business representative and principal investigator must endorse the proposal package. All transactions via ProSAMS are encrypted for security purposes.

If your proposal contains ITAR/EAR information, it may be submitted via ProSAMS.

Do not submit security/password-protected PDF files, as reviewers may not be able to open and read these files. NASA will decline proposal packages containing security/password-protected PDF files and they will not be evaluated.

You are responsible for virus checking all files prior to submission. NASA may decline any proposal package that contains a file with a detected virus.

You may upload a proposal package multiple times, with each new upload replacing the previous version, but only the final uploaded and electronically endorsed version will be considered for review. Embedded animation or video, as well as reference technical papers for “further reading,” will not be considered for evaluation. NASA may decline a proposal package that is missing the final endorsements.

6.1.4 Acknowledgement of a Proposal Package Receipt

NASA will acknowledge receipt of an electronically submitted proposal package by sending an email to the designated Business Official’s email address as provided on the proposal package cover sheet. If you do not receive a proposal package acknowledgment after submission, immediately contact the NASA SBIR/STTR Help

Desk at agency-sbir@mail.nasa.gov.

6.1.5 Withdrawal of Proposal Packages

Prior to the close of submissions, you may withdraw proposal packages. To withdraw a proposal package after the deadline, the designated small business representative must send written notification via email to agency-sbir@mail.nasa.gov.

6.1.6 Service of Protests

Protests, as defined in section FAR 33.101 of the Federal Acquisition Regulation, that are filed directly with an agency, and copies of any protests that are filed with the Government Accountability Office (GAO), must be served on the Contracting Officer (addressed as follows) by obtaining written and dated acknowledgment of receipt from:

mailto:sbir@reisystems.com https://www.acquisition.gov/far/33.101#FAR_33_101

Kenneth Albright

NASA Shared Services Center

Building 1111, Jerry Hlass Road

Stennis Space Center, MS 39529

Agency-SBIR-STTRSolicitation@mail.nasa.gov

The copy of any protest must be received in the office designated above within one day of filing a protest with the

GAO.

6.2 Phase II Information

If you are awarded a Phase I contract, you will be eligible to submit a proposal for an SBIR/STTR Phase II follow-on contract. NASA will send instructions directly to you with information on how to submit your Phase II proposal(s). You will receive details on the due date, content, and submission requirements for Phase II proposals.

The Phase II proposal submission will open approximately 60 days prior to the proposal due date stated in your contract.

If you submit your Phase II proposal outside of the timeframe specified by NASA, your proposal will be declined without evaluation. Additional guidance can be found in your Phase I contract (Request for Proposal for Phase II

Follow-on Contract).

7. Proposal, Scientific and Technical Information Sources

No additional content, requirements, or exceptions beyond information in BAA.

mailto:Agency-SBIR-STTRSolicitation@mail.nasa.gov

8. Submissions Checklist

For assistance in completing your Phase I proposal package, use the following checklist:

□ The technical proposal and innovation are submitted for one subtopic only.

□ The entire proposal package is submitted consistent with the requirements outlined in BAA chapter 3.

□ Proposal Contact Information

□ Proposal Certifications

□ Proposal Summary

□ Proposal Budget

□ Including letters of commitment for government resources and subcontractors/ consultants (if applicable)

□ Foreign Vendor form (if applicable)

□ Technical Proposal including all 9 parts in order as stated in BAA section 3.1.5.5.

□ Briefing Chart

□ NASA Evaluation License Application, only if TAV is being proposed

□ I-Corps Interest Form

□ Technical and Business Assistance (TABA) Request, if applicable

□ SBC-Level Forms completed once for all proposal packages submitted to a single solicitation

□ SBC Certifications

□ Audit Information

□ Prior Awards Addendum

□ Commercialization Metrics Report (CMR)

□ Disclosure of Foreign Affiliations

□ The technical proposal does not exceed a total of 15 standard 8.5- by 11-inch pages with one-inch margins and follows the format requirements (BAA section 3.1.4).

□ All required letters/documentation are included.

□ A letter of commitment from the appropriate government official if the research effort requires use of government resources (BAA sections 3.1.5.4 and 5.13).

□ A letter from the Small Business Official explaining why the SBIR research project requires the use of government resources, if the effort requires government resources (BAA sections 3.1.5.4 and 5.13)

□ Letters of commitment from subcontractors/consultants.

□ If the SBC is an eligible joint venture or a limited partnership, a copy or comprehensive summary of the joint venture agreement or partnership agreement is included.

□ NASA Evaluation License Application if proposing the use of NASA technology (TAV).

□ Supporting documentation of budgeted costs.

□ Total proposed funding for the effort does not exceed $225,000 (BAA section 1.3), and if requesting

TABA, the cost for TABA does not exceed $6,500 (BAA sections 1.8 and 3.1.5.9).

□ Proposed project duration does not exceed thirteen (13) months (BAA section 1.3).

□ Confirm you received an acknowledgement of submission email before 5:00 p.m. ET on May 21, 2026

(Appendix 26B STTR section 6.1.4).

9. Research Topics

The 11 STTR subtopics in this appendix are organized by topic based on technical theme and thus identify subtopics where your research and development capabilities may be a good match. There are 8 topics and 11 total subtopics in this appendix. This appendix only contains STTR subtopics.

You should be thoughtful in selecting a subtopic to ensure the proposal is responsive to the NASA need as defined by the subtopic. The NASA SBIR/STTR program will NOT move a completed proposal package between STTR subtopics.

Guidance for Locating Subtopic Reference Materials

Each subtopic contains references that are intended to provide additional information about the technology need. Some of those references include technical articles that may be available through NASA’s Technical Reports

Server (NTRS) or through other technical journals or sources.

NTRS (https://ntrs.nasa.gov/) provides access to publicly available scientific and technical documents, images and videos created or funded by NASA.

While we work to only reference publicly available documents, if you find that referenced technical articles are behind a paywall, please contact your local library to request assistance in obtaining access.

NASA has changed the subtopic numbering convention for the SBIR/STTR program this year:

Subtopics are organized and numbered according to their topic alignment and appendix. Prior subtopics numbers are listed in the subtopic title as appropriate to help you locate returning subtopics.

https://ntrs.nasa.gov/

Research Subtopics

Aeronautics Research (AERO)

AERO.9.T26B: Full-Scale (Passenger/Cargo) Advanced Air Mobility (AAM) and Vertical Takeoff and Landing

(VTOL) Interdisciplinary Investigations (STTR) (previously T15.04)

AERO.10.T26B: Hybrid Powertrain Technologies (STTR)

GO – Space Transportation (GO)

GO.4.T26B: Modernization of CFD Tools for Advanced Propulsion Applications (STTR)

GO.5.T26B: Very Low Earth Orbits (VLEO) Control Surfaces (STTR)

LIVE – Surface Infrastructure (LIVEI)

LIVEI.2.T26B: Bulk Regolith Manipulation and Site Preparation (STTR)

Science Instruments and Computing to Study Planetary Bodies (INSTALG)

INSTALG.6.T26B: Quantum Computing (STTR) (previously S17.05)

Space Precision Components: Galaxies to Atoms (COSMO)

COSMO.6.T26B: Fundamental Physics Test Apparatus (STTR) (previously S16.08)

Space Weather (SPWX)

SPWX.3.T26B: Quantum Sensing Components for Space Environment Measurements (STTR) (previously

S14.04)

Technology for In Situ Science Operations on Planetary Bodies (INSITU)

INSITU.7.T26B: Combustion and Fluids Experiments (STTR) (previously S15.03)

Unlocking the Orbital Economy (ORBECON)

ORBECON.2.T26B: Biotechnology Applications from Space for Earth (STTR)

ORBECON.3.T26B: Advanced Materials Manufacturing Applications from Space for Earth (STTR)

STTR and the Technology Taxonomy

Aeronautics Research (AERO)

AERO.9.T26B: Full-Scale (Passenger/Cargo) Advanced Air Mobility (AAM) and Vertical

Takeoff and Landing (VTOL) Interdisciplinary Investigations (STTR) (previously

T15.04)

Lead Center: AFRC

Participating Center(s): LaRC

Subtopic Problem Statement/Description:

This subtopic addresses enabling technologies, state-of-the-art design, and analysis tools needed for the Advanced

Air Mobility Pathfinders (AAMP) as well as the cutting-edge concepts of urban air mobility (UAM), distributed electric propulsion (DEP), and propulsion-airframe interaction (PAI).

The subtopic closes a large gap in full-scale Advanced Air Mobility (AAM) and Vertical Takeoff and Landing

(eVTOL) flight vehicle support data. The main focus areas are aerodynamics, propulsion, flight dynamics, controls, and/or acoustics, with potential to address focus areas in combination. Further development, validation and verification of helicopter design and analysis codes and practices are expected for eVTOL vehicles. Proposals should be focused in the areas of full-scale multirotor AAM and eVTOL aircraft design, execution of experiments, and development and validation of scaling methods. In the case of subscale testing, at the completion of Phase II the outcomes are expected to enable and extend the results to all full-scale applications. In the case of full-scale testing and at the completion of Phase II the outcomes are expected to enable future eVTOL testing, provide valuable validation data for design codes, analysis codes, as well as benefits outlined below.

The purpose of the subtopic is to facilitate and accelerate the primary discipline research areas on full-scale vehicles.

Additionally, the subtopic expects to utilize developmental testing of full-scale vehicles by partnering with universities, small business and start-up AAM and VTOL companies. The benefits could include enabling subcomponent testing, providing better decision-making processes, providing lessons learned and best practices, and potentially enabling test beds for future flight and testing experiments.

Full-scale vehicle testing data is still highly sought after for the purposes outlined above, and the modeling and testing is essential for AAM, UAM, DEP, and PAI. Historically, relevant-environment test data are very difficult to obtain due to the challenges associated with planning, executing, and obtaining quality data from testing as well as sensitive/proprietary data issues for companies doing this work. Ultimately, the goal is to model and test multidisciplinary aerodynamics, propulsion, flight dynamics, controls, and/or acoustics.

This subtopic also includes the option for data/testing on subscale vehicles and scaling methods to extend the data to full-scale applications. Scaling methods for flight vehicles have been developed for many decades across the technical areas considered in this subtopic. Subscale testing is often less difficult for various reasons, and it is expected that such proposal may include more expanded test programs and data collection than would be possible at full-scale.

Proposals are sought to: (1) design and execute experiments in order to gather research-quality data to validate aerodynamics, propulsion, flight dynamics, controls, and/or acoustics modeling of full-scale, multirotor eVTOL aircraft, with an emphasis on rotor-interactions with airframe components and other rotors and (2) develop and validate scaling methods to extend and apply the results of instrumented subscale model testing to full-scale applications.

This subtopic is highly relevant and facilitates further research and opportunities to small businesses and research institutions. Under the umbrella of air taxis, Full scale AAM and VTOL vehicles could create a market worth trillions of dollars in the next 15 to 20 years according to some market reports and predictions. Although aerodynamics, propulsion, flight dynamics, controls, and/or acoustics are the focus areas of this subtopic, facilitating flight testing of these vehicles provides many other benefits. A few are providing opportunities for many small businesses to develop and market subsystems and support infrastructure such as batteries, electric motors, propellers, rotors, instrumentation, sensors, manufacturing, vehicle support, vehicle operations, and more.

Expected TRL or TRL Range at completion of the Project: 2 – 6

Primary Technology Taxonomy:

• Level 1: TX15 Flight Vehicle Systems

• Level 2: TX15.1 Aerosciences

Desired Deliverables of Phase I:

Expected deliverables of Phase I awards may include but are not limited to:

• Research and development objectives and requirements

• Initial experiment test plans for gathering experimental results related to the aerodynamic, flight dynamic, control, and/or acoustic characteristics of a multirotor eVTOL aircraft, with an emphasis on interactions between rotors and between the rotors and the vehicle structure for either:

• A full-scale flight vehicle

• A subscale vehicle with fully developed methods for scaling the results to full scale

• Expected results for the flight experiment, using appropriate design and analysis tools

• Design data and performance models for the vehicle and subsystems/components used to generate the expected results

• Preliminary design of the instrumentation and data recording systems to be used for the experiment

• Data that is expected to be collected including data that will be considered proprietary

It is recommended that the awardee provides kickoff, midterm, and final briefings as well as a final report for Phase

I.

Desired Deliverables of Phase II:

Expected deliverables of Phase II awards may include but are not limited to:

• Experimental results that capture aerodynamic, flight dynamic, control, and/or acoustic characteristics of a multirotor eVTOL aircraft, with an emphasis on interactions between rotors and between the rotors and the vehicle structure for either:

• A full-scale flight vehicle

• A subscale vehicle with results extrapolated to full scale

• Design (e.g., CAD, OpenVSP, etc.) and performance models for the experimental vehicle

• Experimental data along with associated as-run test plans and procedures

• Details on the instrumentation and data logging systems used to gather experimental data

• Comparisons between predicted and measured results

It is recommended that the awardee provides kickoff, midterm, and final briefings as well as a final report for Phase

II.

Desired Deliverable Types of Phase II:

• Analysis

• Test Results

• Research (STTR Only)

• Software

• Digital Models

• Hardware

• Prototype

State of the Art:

Integration of distributed electric propulsion (DEP) (4+ rotors) systems into Advanced Air Mobility (AAM) and

Vertical Takeoff and Landing (VTOL) aircraft involves multidisciplinary design, analysis, and optimization

(MDAO) of several disciplines in aircraft technologies. These disciplines include aerodynamics, propulsion, structures, acoustics, and/or control in traditional aeronautics-related subjects.

AAM and VTOL technology is forefront to today's aeronautical innovation and driven by stakeholders in the government, academia and industry. Further innovation within NASA and ARMD will require continued research, facilitation and support.

Critical Gaps:

Innovative approaches in designing and analyzing highly integrated DEP AAM and VTOL aircraft are needed to reduce energy use, noise, emissions, and safety concerns. Such advances are needed to address ARMD’s Strategic

Thrusts #1 (Safe, Efficient Growth in Global Operations), #3 (Ultra-Efficient Subsonic Transports), and #4 (Safe, Quiet, and Affordable Vertical Lift Air Vehicles). Due to the rapid advances in DEP-enabling technologies, current state-of-the-art design and analysis tools lack sufficient validation against full-scale AAM and VTOL flight vehicles, especially in the areas of aerodynamics, propulsion, flight dynamics, controls, and acoustics. Ultimately, the goal is to model and test multidisciplinary aero-propulsive flight dynamics, controls, and acoustics.

Shortfalls And Decadal Surveys:

As an Aeronautics Research Mission Directorate (ARMD) topic it does not tie well into the Civil Space Shortfalls or

Decadal Surveys. It appears from a key word search the document has declined to include ARMD topics. However, if interplanetary exploration using autonomous helicopters or other aero vehicles is underlying any of these shortfalls, this subtopic area would be directly applicable to advancing those technologies.

This subtopic aligns with NASA aeronautics legacy mission to make subtle low cost and low risk improvements through research and testing. Reference the critical gaps section.

Need Horizon: Mid-Term (5-10 years)

References:

• NASA/ARMD/Advanced Air Vehicles Program (AAVP): Nateri Madavan

• Subsonic Vehicle Technologies and Tools (SVTT) project: Tony Nerone.

• ARMD/Advanced Air Transport Technology (AATT) Project: Dr. Dale Van

Zante https://www.nasa.gov/aeroresearch/programs/aavp/aatt https://www.nasa.gov/aeroresearch/programs/aavp/aatt

• ARMD/Revolutionary Vertical Lift Technology (RVLT) Project: Noah

Schiller https://www.nasa.gov/aeroresearch/programs/aavp/rvlt

• ARMD/Transformative Aeronautics Concepts Program (TACP):Dr. John Cavolowsky

• ARMD/Transformational Tools and Technologies (TTT) Project: Azlin Biaggi-

Labiosa https://www.nasa.gov/aeroresearch/programs/tacp/ttt

• ARMD/University Innovation (UI) Project: Gelsomina (Mina)

Cappuccio https://www.nasa.gov/aeroresearch/programs/tacp/ui

• ARMD Strategic Implementation Plan:

• AOSP/Airspace and Operations Safety Program: Akbar Sultan

• Advanced Capabilities for Emergency Response Operations Project: Dr. Min Xue

AERO.10.T26B: Hybrid Powertrain Technologies (STTR)

Lead Center: GRC

Subtopic Problem Statement/Description:

Hybrid powertrain technologies comprise all of the major pieces of electrified vehicles that enable multiple energy sources to combine to propel the aircraft forward. A common example would be a system where batteries, though an electric powertrain system, assist in turning the shaft of a gas turbine engine, but there are many other topologies as well. This subtopic in general is intended to cover the range of hybridization for commercial aircraft. This year, the subtopic is focused on the subset which is described as "high power electrified aircraft propulsion (EAP)" or "high power EAP".

High Power EAP technologies are aimed at enabling high percentage electrification of propulsion systems for regional and single aisle aircraft. These require power dense, components and systems that can handle 10 MW of total power or more depending on the airframe and mission design requirements. Such systems range from electric machines (motors and generators) to power electronics and devices (inverters, converters, circuit breakers etc.) to cables and connectors.

Superconducting systems are of particular interest for high power EAP due to their potential for extremely high specific power and efficiencies. While significant progress has been made to date in this area, there is a need for further development in order to address the final gaps for application in the field (entry into service). Of specific interest for this subtopic call are technologies for superconducting electric machines and the cryo-compatible power electronics that support them.

In the area of power electronics that work with superconducting systems, there is a specific need for optoelectronics solutions to operate at or near the operational temperatures of both the electric machines and the superconducting cabling which connect them to the rest of the system (temperature ranges from 20K-40K).

Cryo-compatible power electronics solutions are sought with the following as a reference design:

A total power inverter solution for a multi-megawatt devices operating at the stated cryogenic temperatures with application to a superconducting motor spinning at a steady fundamental frequency of 500 Hz to 1000 Hz, 2-5 MW total output power (can be modular) at 1.5-2.5 kV, and with ultra-low total harmonics distortion (nearly a pure sine wave).

https://www.nasa.gov/aeroresearch/programs/aavp/rvlt https://www.nasa.gov/aeroresearch/programs/tacp/ttt https://www.nasa.gov/aeroresearch/programs/tacp/ui

Proposed inverters are welcome, and also enabling subcomponents and technologies such as:

• Cryo-compatible gate drives for Gallium Nitride (GaN) High Electron Mobility Transistors (HEMT) based power electronics

• Hermetic connectors for high power, high voltage (1-3kV, 75-500A) , cryogenic motor drives (a solution here may include the entire power electronics enclosure and heat sink(s)

• Active EMI filtering specific to GaN HEMT based systems to reduce filtering weight

Other areas of where proposal are sought under this subtopic are:

• Cryo-compatible partial discharge measurement capabilities (hardware and integrated detection system)

• Light weight cryo fans for gaseous helium (possible helium/hydrogen combination) for high flow rates

(50+ m^3/hr or greater)

Note: This subtopic is for electric powertrain components between the electric energy source (i.e. battery or fuel cell) and the shaft (as in the case of turboprop or turbine engine shaft), focusing on superconducting or other high power but extremely power dense and efficient solutions.

Expected TRL or TRL Range at completion of the Project: 2 – 4

Primary Technology Taxonomy:

• Level 1: TX15 Flight Vehicle Systems

• Level 2: TX15.1 Aerosciences

• Level 3: TX15.1.1 Aerodynamics

Desired Deliverables of Phase I:

Phase I Deliverables:

• Design of an initial protype and proof of principal in the form of a study or test (or both) that support the initial designs to meet the stated goals in a reverent environment

• Report describing the design, test and analysis results and recommendations for work beyond Phase I.

Desired Deliverables of Phase II:

Phase II Deliverables:

• Prototype(s) capable of being integrated into a larger system. The prototype(s) should be accompanied by test data showing the device working in conditions like those in the final applications

• Report describing final design, test and analysis results, analysis of ability to integrate into a reference system such as NASA's multi-megawatt high power motor and drive system or similar (NASA will work with awardee to help define this).

• Estimation of technology gaps remaining for the given approach

• Delivery of prototype hardware as an option

Desired Deliverable Types of Phase II: Analysis, Test Results, Prototype, Hardware

State of the Art:

The state-of-the-art for aircraft with 5-10 Megawatt (MW) or greater onboard power is defined by ground demonstration for subscale systems alongside aircraft studies and work on cryogenic fuel systems. Systems providing up to 1 Megawatt of power are beginning to see flight demonstration and much progress has been made toward understanding how to derive benefits from electrified propulsion while meeting flight safety standards.

Larger planes with higher power levels require another step change in performance for the components themselves, and more highly integrated. The treatment of the thermal interactions on an airplane level is of particular importance as designers strive to extract more benefit. Work in this area is laying a foundation for future airplanes and future airspaces which can adapt to alternate fuels such as liquid hydrogen.

Critical Gaps:

NASA is pushing power levels, voltages and cooling system requirements to reduce weight while increasing power. For this application there are solutions that work at ambient temperatures but are either unproven or known to not work at cryogenic temperatures that are required for superconducting systems.

Significant progress has been made over the past decade in the area a of electrified aircraft propulsion. Prototype aircraft, major ground tests and flight demonstrators have succeeded with systems ranging from 100s of kilowatts to a megawatt. These power levels allow full electrification of urban air mobility vehicles (2-6 passengers) or mild hybridization of single aisle aircraft propulsion systems. While these prototypes and demonstrators are a significant step in the electrification of propulsion systems for aviation, it still falls short of the 2016 National Academies

Decadal Survey, “Commercial Aircraft Propulsion and Energy Systems Research: Reducing Global Carbon

Emissions Recommendations.” This survey recommended the investigation of fully turboelectric single aisle aircraft. To do this requires developing systems that are capable of handling more than 10 megawatts alongside more radical changes to the airframe and more highly integrated designs.

The ultra-high efficiencies offered by superconducting systems are attractive for such applications, but there are a number of supporting technologies that must be more fully developed before the superconducting motors and distributions systems can be realized in an aircraft propulsion system. This subtopic is meant to address targeted technologies that need immediate action in order to drive this technological area forward.

Shortfalls And Decadal Surveys:

https://www.nationalacademies.org/projects/DEPS-ASEB-14-03/publication/23490 https://www.icao.int/Meetings/a41/Documents/WP/wp_368_en.pdf https://www.faa.gov/sites/faa.gov/files/2021-11/Aviation_Climate_Action_Plan.pdf https://www.mckinsey.com/industries/aerospace-and-defense/our-insights/future-air-mobility-blog/fuel-efficiency-why-airlines-need-to-switch-to-more-ambitious-measures

Need Horizon: Long Term (Greater than 10 years)

References:

1. Megawatt and Beyond, NASA's Electrified Aircraft Propulsion, Dr. Andrew Woodworth https://ntrs.nasa.gov/api/citations/20250006231/downloads/PEASA2025%20-STI.pdf

2. https://ntrs.nasa.gov/api/citations/20250006231/downloads/PEASA2025%20-STI.pdf

3. NASA Interests in Superconducting and Cryogenic Technology, Dr. Justin Scheidler https://ntrs.nasa.gov/api/citations/20240008976/downloads/2024%20Navy%20HTS%20Review%20-

%20Scheidler.pdf https://www.nationalacademies.org/projects/DEPS-ASEB-14-03/publication/23490 https://www.icao.int/Meetings/a41/Documents/WP/wp_368_en.pdf https://www.faa.gov/sites/faa.gov/files/2021-11/Aviation_Climate_Action_Plan.pdf https://www.mckinsey.com/industries/aerospace-and-defense/our-insights/future-air-mobility-blog/fuel-efficiency-why-airlines-need-to-switch-to-more-ambitious-measures https://www.mckinsey.com/industries/aerospace-and-defense/our-insights/future-air-mobility-blog/fuel-efficiency-why-airlines-need-to-switch-to-more-ambitious-measures https://ntrs.nasa.gov/api/citations/20250006231/downloads/PEASA2025%20-STI.pdf https://ntrs.nasa.gov/api/citations/20250006231/downloads/PEASA2025%20-STI.pdf https://ntrs.nasa.gov/api/citations/20240008976/downloads/2024%20Navy%20HTS%20Review%20-%20Scheidler.pdf https://ntrs.nasa.gov/api/citations/20240008976/downloads/2024%20Navy%20HTS%20Review%20-%20Scheidler.pdf

4. Contractor Report on Boeing SUGAR Studies Subsonic Ultra Green Aircraft Research: Phase 2: Hybrid

Electric Design Exploration - Volume 2 - NASA Technical Reports Server (NTRS)

GO – Space Transportation (GO)

GO.4.T26B: Modernization of CFD Tools for Advanced Propulsion Applications (STTR)

Lead Center: MSFC

Participating Center(s): GRC

Subtopic Problem Statement/Description:

Predictive, analytical modeling of subcritical combustion physics is a challenge that bridges several state-of-the-art and state-of-the-practice limitations of currently available models. Practically all spacecraft propulsion systems operate in a subcritical propellant injection regime during nominal operations. The maturation of advanced chemical propulsion systems with high efficiency and reliability is critical to NASA’s missions for human exploration on the

Moon and Mars. Development of these systems requires robust and accurate computational fluid dynamics (CFD) models to help guide design decisions and understand combustion dynamics and performance observed in testing or operation.

Rotating Detonation Rocket Engines (RDREs) operate by injecting liquid fuel and/or oxidizer into an annular combustion chamber. These propellants are initially in a liquid state and undergo liquid break-up and atomization once introduced into the combustion chamber as dictated by their fluid properties and injection dynamics. In an

RDRE application, a supersonic combustion wave impacts the injected propellent stream, further atomizing the injected fuel and oxidizer streams to enhance combustion in an unsteady combustion environment. The potential advantages of RDREs have led to great interest in development of flight-scale RDREs, but with limited success to date due in part to a lack of understanding of the complex multiphase fluid injection and combustion physics.

In traditional, subsonic combustion rocket engines, the initial start-up operation of the engine requires that the fuel and oxidizer are injected in a subcritical fluid regime. The success of the rocket engine performance relies on characterization of ignition and combustion dynamics. In the case of liquid hypergolic rocket engines, liquid fuel and oxidizer are injected, break up and atomize, undergo extremely energetic liquid-liquid chemical reactions and simultaneous vaporization followed by gas-phase chemical reactions, with a range of timescales from microseconds to tens of milliseconds. Hypergolic engines have been plagued with damaging transient combustion events throughout the history of their development, with mitigations typically resulting from extensive test campaigns to develop operational keep out zones, with significant residual risk due to a lack of physical understanding of these transient combustion events.

Predictive analytical models could potentially avoid engine development issues and ensure reliable, predictable combustion dynamics across the range of liquid rocket engines from traditional chemical, hypergolic, to RDRE.

There are currently no validated or even pragmatic analytical tools that can predictively model the physics of subcritical propellant injection, break-up, phase change and combustion. Model development in these areas of subcritical liquid injection and break-up, interface tracking, phase change, and multiphase combustion kinetics mechanisms are needed in order to develop predictive analytical tools that can be used in the design of advanced chemical propulsion systems. Particular focus should be placed on coupling subcritical approaches to existing methodologies used for trans- and supercritical regime flows.

https://ntrs.nasa.gov/citations/20150017039 https://ntrs.nasa.gov/citations/20150017039

Expected TRL or TRL Range at completion of the Project: 2 - 5

Primary Technology Taxonomy:

• Level 1: TX11 Software, Modeling, Simulation, and Information Processing

• Level 2: TX11.3 Simulation

• Level 3: TX11.3.7 Multiscale, Multiphysics, and Multifidelity Simulation

Desired Deliverables of Phase I:

Development of an analytical model capable of simulating injection of multiple liquid species into a highly turbulent gaseous region representative of a combustion chamber. The model should be able to capture the physics of liquid break-up, initially modeled using a sharp-interface method (e.g., volume of fluid or phase field), into droplets that then evaporate into the background gas while conserving mass, momentum and energy. Demonstration of a proof-of-concept simulation for a lab-scale combustion chamber at relevant conditions.

Desired Deliverables of Phase II:

Development of an analytical model that captures the fully coupled physics between propellant injection at subcritical conditions through liquid break-up and finally coupled with a gas-phase combustion model. The analytical model shall be extended to model liquid-liquid hypergolic reactions prior to gas-phase hypergolic reactions as a secondary objective. The final analytical model must be validated to the best degree possible with available combustion chamber test data and demonstrated on a 3-D, realistic combustion application that is relevant to NASA. The final model must also be scalable to full-sized space flight engines and efficient enough to justify the value of the analytical model as a tool for propulsion system development. The model should be formulated to accommodate implementation in a graphics processing unit (GPU)-accelerated finite-volume framework.

Desired Deliverable Types of Phase II:

• Analysis

• Software

State of the Art:

The current state-of-the-art (SOA) for CFD modeling of subcritical liquid injection and combustion involves the use of an interface-tracking method to represent the gas-liquid interface of the injector spray, transitioning to an Eulerian or Lagrangian representation of the droplet field once the length scales of individual droplets can no longer be resolved by the computational mesh. Heat transfer to the droplets is modeled stochastically, resulting in evaporation, mixing, and combustion of the gas phase.

Critical Gaps:

In practice, the SOA models are computationally expensive, requiring extremely high spatial resolution, and are not numerically robust enough to conduct simulations of realistic many-element injector designs in a useful timeframe without enormous computational resources. Droplet breakup and heat transfer models are based on data from experiments relevant to traditional subsonic combustion chambers, which may not be appropriate for evolving engine technologies such as RDREs. Currently, no practical models exist for simulation of liquid-liquid reactions as found in the combustion of hypergolic fuels.

Shortfalls And Decadal Surveys:

NASA Civil Space Shortfall 1511 - Advance Computational Fluid Dynamics Tools/Capabilities

Need Horizon: Near-Term (Less than 5 years)

References:

1. Reveillon J. and Vervisch, L., “Analysis of weakly turbulent dilute-spray flames and spray combustion regimes.” J. Fluid Mech., vol. 537, pp. 317–347 (2005).

2. Chigier, N. 1983 Group combustion models and laser diagnostic methods in sprays: a review. Combust.

Flame 51, 127–139.

3. Cheng, G. & Farmer, R., “CFD Spray Combustion Model for Liquid Rocket Engine Injector Analysis,”

AIAA Paper No. 2002-0785 (2002).

4. E. B. Coy, S. C. Greenfield, M. S. Ondas, Y. -H. Song, T. D. Spegar, and D. A. Santavicca “Droplet turbulence interactions under subcritical and supercritical conditions.” NASA Propulsion Engineering

Research Center, Volume 2. Nov. 1st, 1993. NTRS: 19940018563.

5. Batista, A., Burr, J., Ross, M., Harvazinski, M., and Paulson, E., “Spatiotemporal Sensitivity in

Rotating Detonation Rocket Engine Large Eddy Simulations.” AIAA paper 2026-2419, AIAA SciTech

Forum, Orlando, FL, January 2026.

6. Sardeshmukh, S.V., “Comprehensive Computational Modeling of Hypergolic Propellant Ignition.” Ph.D.

Dissertation, Purdue University, 2013.

GO.5.T26B: Very Low Earth Orbits (VLEO) Control Surfaces (STTR)

Lead Center: GRC

Participating Center(s): MSFC, AFRC

Subtopic Problem Statement/Description:

Very low Earth orbits (VLEOs), defined as 80 – 400 km (ref.), are becoming of interest due to uncertainties in their composition, ionization levels, and movement patterns1. In particular, The altitude ranges from ~80 to ~160 km— that is, the D- and E-regions of the ionosphere—is a critical region where key aspects of the energy and momentum transport between the M-I-T (Mesosphere/Ionosphere/Thermosphere) system take place. While previous LEO missions have provided information on the magnetospheric input into the upper atmosphere and ionosphere—as well as preliminary insight into its response—these missions have been unable to probe the mechanisms of coupling. Concepts for orbital “dipper” missions that regularly dip into very low Earth orbit (VLEO; i.e., the E-region ionosphere) have been circulating in the community for several decades, no such mission has yet been implemented to answer these questions.2

Orbits at low altitudes will be defined by high relative spacecraft speeds: circular orbits are on the order of 7-8 km/s, equivalent to an approximate Mach number of 25. This is therefore a regime of rarefied gases and hypersonic flow. In this regime, spacecraft will encounter aerodynamic forces, particularly at the lowest altitudes, that will influence spacecraft orbits through drag. Also, in the regimes between 80 and 200 km, propellant efficient electric propulsion will not be possible due to the magnitude of the drag and composition and density of the atmosphere at those altitudes. Extended missions passing through lowest altitudes will therefore need to address some combination of

1. minimizing drag,

2. countering drag with propulsion using either on board or ambient propellant, https://arc.aiaa.org/doi/10.2514/6.2026-2419 https://arc.aiaa.org/doi/10.2514/6.2026-2419

3. and/or possibly adapting the spacecraft to take advantage of the available aerodynamic forces to maintain orbit and/or change orbits.

One successful example of maneuvering in this regime is the USSF X37b spaceplane, which has demonstrated aerobraking to change orbits aerodynamically3. To date, civil satellite missions or designs in the VLEO regime

(ASTRE2, SOAR4) have not used control surfaces on their spacecraft to maintain orbit. For example, the proposed

ASTRE mission would use hydrazine propulsion to remain on orbit; SOAR started at ~400 km and reentered within

8 months.

To date, open tests of satellites in the VLEO regime (ASTRE2, SOAR4) have not used control surfaces on their spacecraft. Additional lift/steering forces from such surfaces would allow longer satellite durations and greater data collection. The desired products of this subtopic are therefore the design of either aerodynamic components, or a combination of such components with a viable propulsion system, to maintain orbit, or perform orbital maneuvers, at orbital altitudes that are not just VLEO, but particularly in the 80 km – 120 km region.

Expected TRL or TRL Range at completion of the Project: 2 - 3

Primary Technology Taxonomy:

• Level 1: TX15 Flight Vehicle Systems

• Level 2: TX15.X Other Flight Vehicle Systems

• Level 3: TX15.1.6 Advanced Atmospheric Flight Vehicles

Desired Deliverables of Phase I:

Phase 1 Products would be:

1. VLEO environmental model

2. Aerodynamic spacecraft surface design

4. Propulsion system design if needed

5. Identification of potential maneuvers, or mission durations, that could be expected with the systems

6. Identification of possible test facilities validation in Phase 2

Desired Deliverables of Phase II:

Phase 2 Products would be:

1. Test article (aerodynamic system to be tested)

2. Test design

3. First experimental test results demonstrating lift, drag, and moments

Desired Deliverable Types of Phase II:

• Analysis,

• Test Results

• Hardware

• Prototype

State of the Art:

The altitude ranges from ~80 to ~160 km—that is, the D- and E-regions of the ionosphere—is a critical region where key aspects of the energy and momentum transport between the M-I-T system take place. This region is immensely important because it is the altitudinal crossroads where ionospheric electrodynamics (e.g., Joule heating and current closure) occur in concert with significant neutral densities and thermospheric processes (e.g., neutral winds). Unfortunately, despite the importance of this region in understanding the intricacies of the coupled near-Earth space system, it remains woefully underexplored with most focused investigations coming from the sounding rocket program. The paucity of measurements in this region stems from the general inability to investigate these altitudes using orbital spacecraft owing to substantial atmospheric drag that arises from the combination of required high orbital velocities and relatively large plasma and neutral densities at altitudes below ~400 km.

Critical Gaps:

Aerodynamic maneuvering designs for 80 to 160 km

Efficient propulsion at 80 to 160 km

Shortfalls And Decadal Surveys:

Perform advanced remote sensing and science measurements with improved sensing capabilities and autonomy.

Provide space technology demonstration environments.

Need Horizon: Mid-Term (5-10 years)

References:

1. Pfaff, R., et al., “The Atmosphere-Space Transition Region Explorer (ASTRE) – A Low Perigee Satellite to

Investigate the Coupling of the Earth’s Upper Atmosphere and Magnetosphere,” NASA/TP–20220018963, https://ntrs.nasa.gov/citations/20220018963 .

2. https://www.nationalacademies.org/publications/27938

3. https://www.spaceforce.mil/News/Article-Display/Article/4112259/x-37b-orbital-test-vehicle-concludes-seventh-successful-mission/

4. Crisp, N. H., Macario Rojas, A., Roberts, P., Edmondson, S., Haigh, S. J., Holmes, B. E. A., Oiko, V. T.

A., Sinpetru, L. A., Smith, K. L., & et al. (Accepted/In press). Experimental Results from the Satellite for

Orbital Aerodynamics Research (SOAR) Mission. In 73rd International Astronautical Congress

LIVE – Surface Infrastructure (LIVEI)

LIVEI.2.T26B: Bulk Regolith Manipulation and Site Preparation (STTR)

Lead Center: KSC

Participating Center(s): LaRC, ARC, GRC

Subtopic Problem Statement/Description:

Some of the first possible lunar infrastructure will be prepared surfaces composed of bulk regolith, rocks and other surface treatments. This subtopic will develop civil engineering designs of prepared lunar surface infrastructure, technologies to build the infrastructure, and construction concepts of operations (ConOps) for the South Polar region of the Moon. The intention of this subtopic is to prepare the systems that can stimulate commercial space resource based economic activity through robotic regolith manipulation and site preparation. Products and services that can be offered to the market by the proposed technologies should be specified along with realistic pricing. Development of financial engineering constructs to facilitate the exchange of goods and services are also desired. Proposals should be compatible with the Lunar Innovation Park (Park) concept described in the references and with Fission Surface https://ntrs.nasa.gov/citations/20220018963 https://www.nationalacademies.org/publications/27938 https://www.spaceforce.mil/News/Article-Display/Article/4112259/x-37b-orbital-test-vehicle-concludes-seventh-successful-mission/ https://www.spaceforce.mil/News/Article-Display/Article/4112259/x-37b-orbital-test-vehicle-concludes-seventh-successful-mission/

Power (FSP) emplacement and radiation protection applications. Park and FSP missions are the infusion path for this subtopic.

Earth-based civil engineering materials, processes and technologies are not adequate for lunar construction, therefore lunar civil engineering designs and construction technologies must be developed. The fundamental robotic capabilities of interest are:

• High resolution topography mapping.

• Geotechnical measurement.

• Rock removal and management.

• Establishing grade and forming desired ground features (e.g., berms, ramps, and level surfaces).

• Compaction.

• Anchoring for foundations and stabilizing structures (e.g., guy-wires)

• Verification of infrastructure design parameters and geometry of built structures.

• Surface treatments to mitigate PSI ejecta and dust.

• Routines, sensors, and ultrawideband beacons for autonomous construction operations and localization.

• Radiation sensors for space and FSP radiation measurements to assess radiation protection characteristics of built structures.

The desired outcome of this effort is the robotic capability to perform site preparation and regolith manipulation…