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Spacecraft Thermal Management

Description:

Scope Title:

Lunar Habitat Thermal Technologies

Scope Description:

NASA is seeking focused efforts to develop thermal control technologies that will enable crewed habitats for extended stays on the lunar surface. Technologies should address a gap associated with long-duration habitation on the lunar surface, where temperatures range from -193 °C or lower in shadowed regions (including night) to 120 °C at the equatorial subsolar point. Technologies are needed that allow a single habitat or a pressurized rover to operate in all these environments. Technologies should address reduction in mass, volume, and power usage relative to current solutions. The addition of heaters can lead to increased vehicle mass due to additional power generation and storage requirements and is not considered a novel architecture approach. Proposed radiator technologies should also address micrometeoroid and orbital debris (MMOD) robustness and protection potential where appropriate.

Examples of other challenges to address in this area include, but are not limited to, the following:

  • Methods for preventing or restoring radiator optical properties that have degraded due to exposure to the space environment (radiation, etc.).
  • Development of engineered solar reflective coating with high infrared (IR) transparency with the following properties:
    • Solar reflectance >0.85 (threshold) to 1 (goal).
    • IR transmittance >0.85 (threshold) to 1 (goal).
    • Is electrically dissipative, i.e., low exposed surface resistivity (to manage potential static charge buildup).
    • Is compatible with a variety of substrates: novel thermochromic materials, standard spacecraft metals, and flexible thermal control tapes.
  • Contamination-insensitive evaporators/sublimators to enable long mission life.
  • Self-healing coolant tubes for MMOD-impact resilience.
  • Incorporation of elastocaloric heat pumps into a payload thermal control system.
    • ~50 to 100 W of heat lift.
    • Cold side temperature <4 °C.
    • Hot side temperature ~ambient (heat sunk to air or liquid cooled interface).

Unless otherwise stated, technologies should be suitable for use with crewed vehicles having variable heat loads averaging between 2 and 6 kW and should consider dormancy (mission time while uncrewed) impacts. All technologies should support a minimum operational duration of at least 5 years and be compatible with applicable mission environments. For example, ground processing/launch site environments (humidity, general contamination, etc.) and in-space environments (ultraviolet (UV), solar wind, etc.).

Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 14 Thermal Management Systems
  • Level 2 14.2 Thermal Control Components and Systems

Desired Deliverables of Phase I and Phase II:

  • Analysis
  • Prototype
  • Hardware
  • Software

Desired Deliverables Description:

Phase I awards in this area are expected to demonstrate analytical and/or empirical proof-of-concept results that demonstrate the ability of the organization to meet the goals stated in the solicitation.

At the conclusion of a Phase II contract, deliverables are expected to include a functioning prototype (or better) that demonstrates the potential to meet the performance goals of the technology or software. Any delivered math models should include supporting data that validate the assumptions used within the model.

State of the Art and Critical Gaps:

This scope strives to reduce mass, volume, and power of a thermal control system in the next generation of robotic and human-class spacecraft and to enable long-term missions to the Moon. The current state of the art in thermal control systems is vehicle power and mass impact of greater than 25 to 30% due to old technologies still in use. Furthermore, as missions become more variable (dormancy, environments, etc.), the need for intelligent design and control (both actively and passively) within the thermal control system becomes more apparent. Namely, the need to provide variable heat rejection through the complex lunar temperature profile has provided the opportunity for many novel heat rejection system technologies to be developed and evaluated. However, among the most significant challenges associated with modulating radiator efforts is the ability to provide the desired optical properties in the solar spectra while achieving the desired IR transmission for tunable products. An engineerable solar reflective coating with high transmission in the IR spectra is expected to address this gap while also providing a general tool capability to tune solar and IR properties of static coatings. This scope also acknowledges the need to improve system robustness while minimizing impact to other systems. 

Relevance / Science Traceability:

  • Deep space habitats and crewed vehicles (Moon, Mars, etc.)
    • Orion
    • Gateway
    • Human Landing System (HLS)
  • Mars transit vehicles
  • SmallSats/CubeSats
  • Rovers and surface mobility

References:

  1. Stephan, R. Overview of the Altair Lunar Lander Thermal Control System Design and the Impacts of Global Access. AIAA 2011-5001. 2011.
  2. Ewert, M.K. Investigation of Lunar Base Thermal Control System Options. SAE Transactions. J. of Aerospace. 102(1). 829-840. 1993.
  3. Kauder, L. Spacecraft Thermal Control Coatings References. NASA/TP-2005-212792. 2005.
  4. Dudon, J.P., et al. Development of Variable Emissivity Coatings for Thermal Radiator. ICES-2021-063. 50th International Conference on Environmental Systems. July 2021.
  5. Snodgrass, R., and Erickson, D. A Multistage Elastocaloric Refrigerator and Heat Pump With 28 K Temperature Span. Sci Rep 9, 18532. 2019.

Scope Title:

High-Temperature Heat Acquisition and Transport

Scope Description:

NASA is seeking the development of thermal transport systems for spacecraft applications that require the transfer of large amounts of thermal energy from a reactor (e.g., nuclear) to a power conversion system. NASA desires a high-temperature heat transfer system capable of transferring 4 to 10 MW of thermal power from a reactor, at a supply temperature of 1,200 to 1,400 K with a flux on the order of 0.3 MW/m2 with a goal of 1 MW/m2, to the hot-end heat exchangers of an electric power conversion system. A maximum system temperature drop of 50 to 150 K from the reactor interface to power conversion working fluid is also desired. The target distance for the power conversion system is 5 m from the reactor, but transport distances up to 10 m may be required. The system needs to be gamma- and neutron-radiation tolerant, single-fault tolerant (a single leak should not render the system inoperable), and have an operating life of 15+ years. System mass and reliability should be addressed as part of the proposal.

Example solutions include, but are not limited to, liquid metal heat pipes or pumped fluid loops. Special consideration should be given to interfaces (both at the reactor and at the power conversion system) to maximize heat transfer. Integration with the reactor may include solutions that run through the reactor core. For integration with the power conversion system, a helium-xenon working fluid in a Brayton cycle system may be assumed but is not required.

Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 14 Thermal Management Systems
  • Level 2 14.2 Thermal Control Components and Systems

Desired Deliverables of Phase I and Phase II:

  • Analysis
  • Prototype
  • Hardware
  • Software

Desired Deliverables Description:

Phase I awards in this area are expected to demonstrate analytical and/or empirical proof-of-concept results that demonstrate the ability of the organization to meet the goals stated in the solicitation.

At the conclusion of a Phase II contract, deliverables are expected to include a functioning prototype (or better) that demonstrates the potential to meet the performance goals of the technology or software. Any delivered math models should include supporting data that validate the assumptions used within the model.
 

State of the Art and Critical Gaps:

This scope strives to reduce mass, volume, and power of a thermal control system in the next generation of robotic and human-class spacecraft and to enable long-term missions to the Moon and Mars. Namely, few design technologies exist that are capable of managing the heat transport between nuclear reactor and power conversion systems with high efficiency. This is a critical element of nuclear electric propulsion working architecture that must be improved to increase the viability of future systems. The ability to transport very high heat loads over considerable distances, with high transport efficiency, is expected to be a gap for future space systems that utilize nuclear energy.

 

Relevance / Science Traceability:

  • Nuclear electric propulsion (NEP) systems
  • Nuclear power system (lunar surface power)

References:

  1. Wetch, J.R., et al. Megawatt Class Nuclear Space Power Systems (MCNSPS) Conceptual Design and Evaluation Report, Volumes I-IV. NASA-CR-179614. September 1988.
  2. General Atomics Project 3450. Thermionic Fuel Element Performance Final Test Report, TFE Verification Program. GA-A21596 (UC-224). Prepared under Contract DE-AC03-86SF16298. Department of Energy. 1994.
  3. Ashcroft, J. and Eshelman, C. Summary of NR Program Prometheus Efforts. LM-05K188. 2006.
  4. Aerojet. SNAP-8 Performance Potential Study, Final Report. NASA-CR-72254. 1967.
  5. Horner-Richardson, K., et al. Fabrication and Testing of Thermionic Heat Pipe Modules for Space Nuclear Power Systems. 27th IECEC, San Diego, CA. Paper Number 929075. 1992.
  6. Ernst, D.M. and Eastman, G.Y. High Temperature Heat Pipe Technology at Thermacore – An Overview. AIAA-85-0981. 1985.
  7. Voss, S.S. and Rodriguez, E.A. Russian System Test Program (1970-1989). American Institute of Physics Conference Paper 94-0101. 1994.
  8. Stone, J.R. Alkali Metal Rankine Cycle Boiler Technology Challenges and Some Potential Solutions for Space Nuclear Power and Propulsion Applications. NASA-TM-106593. July 1994.
  9. Demuth, S.F. SP 100 Space Reactor Design. Progress in Nuclear Energy. 42(3). 2003.
  10. Ashcroft, J. and Eshelman, C. Summary of NR Program Prometheus Efforts. LM-05K188. 2006.
  11. Davis, J.E. Design and Fabrication of the Brayton Rotating Unit. NASA-CR-1870. March 1972.
  12. Richardson-Hartenstein, K., et al. Fabrication and Testing of Thermionic Heat Pipe Modules for Space Nuclear Power Systems.” 27th IECEC, Paper Number 929075. 1992.

Scope Title:

Topology Optimization of Thermal Control Systems

Scope Description:

Advanced design and manufacturing are rapidly transforming engineered systems. The advent of reliable additive manufacturing techniques coupled with robust optimization algorithms is facilitating the development of new high-performance systems. To date, the advanced design community has primarily focused on optimized structural systems that minimize mass and volume while meeting structural performance requirements. While some work has been done to develop advanced topology optimization (TO) design tools for thermal control systems involving fluid flow heat exchangers, considerable work remains to make the use of those tools standard practice for a wider range of spacecraft thermal systems that include radiation heat transfer.

This solicitation requests the development and demonstration of either pre-existing or new TO software that can optimize spacecraft thermal radiator architectures, minimizing mass and maximizing heat transfer efficiency. NASA requests limited usage rights of compiled software at the completion of this SBIR period.

Recommended optimization variables shall include radiator size, thickness, and shape. Input variables shall include radiator heat load, environmental heat load, nonuniform view factor blockage, and radiator structural support locations.

The optimization process shall be demonstrated. Documented savings in mass shall be trended along each step of the optimization path. The optimization algorithm should be sufficiently versatile to solve generalized coupled thermal conduction and radiation problems.

Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 14 Thermal Management Systems
  • Level 2 14.2 Thermal Control Components and Systems

Desired Deliverables of Phase I and Phase II:

  • Analysis
  • Prototype
  • Hardware
  • Software

Desired Deliverables Description:

Phase I awards in this area are expected to demonstrate analytical and/or empirical proof-of-concept results that demonstrate the ability of the organization to meet the goals stated in the solicitation.

At the conclusion of a Phase II contract, deliverables are expected to include a functioning prototype (or better) that demonstrates the potential to meet the performance goals of the software. Any delivered math models should include supporting data that validate the assumptions used within the model.
 

State of the Art and Critical Gaps:

These scopes strive to reduce mass, volume, and power of a thermal control system in the next generation of robotic and human-class spacecraft and to enable long-term missions to the Moon and Mars. These improvements may come through either novel hardware solutions or modernization of software tools. The current state of the art in thermal control systems is vehicle power and mass impact of greater than 25 to 30% due to old technologies still in use. Furthermore, as missions become more variable (dormancy, environments, etc.), the need for intelligent design and control (both actively and passively) within the thermal control system becomes more apparent. Topology optimization (TO) in particular has become a well-established structural design tool, but it has yet to penetrate the thermal design community. Multiple research efforts have shown that TO of thermal-fluid systems is possible and can be successfully implemented to obtain optimized designs; however, a robust commercial code that is capable of doing this is yet to be demonstrated. Additionally, science payloads will continue to decrease in size, increase in power, and require precise temperature control, all of which cannot be readily provided by traditional thermal control methods due to vehicle-level impacts of overall performance, mass/volume, and power.

Relevance / Science Traceability:

  • Mars transit vehicles
  • SmallSats/CubeSats
  • Rovers and surface mobility
  • Nuclear electric propulsion (NEP) systems
  • Future science missions

References:

  1. Watkins, R. Designing optical instruments for space applications: Multiphysics topology optimization. 2019.
  2. Watkins, R. Topology optimization: a shift towards computational design. 2016.
  3. Kambampati, S., Gray, J., and Kim, H.A. Level set topology optimization of load carrying heat dissipation devices. AIAA Aviation 2019 Forum. 2019.
  4. Kambampati, S., and Kim, H.A. Level set topology optimization of cooling channels using the Darcy flow model. Structural and Multidisciplinary Optimization. 1-17. 2020.
  5. Feppon, F., et al. Topology optimization of thermal fluid–structure systems using body-fitted meshes and parallel computing. Journal of Computational Physics. Vol. 417, 109574. 2020.

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