MCF > Detailed Design and Analysis > Mechanical and Thermal >
Scope and Description
This topic covers thermal analysis of spacecraft hardware – from full spacecraft to subsystems and components. This includes processes used to simulate or otherwise estimate response to thermal control devices, loads, and changing environmental conditions (e.g. sunlight). Modeling of these inputs and spacecraft hardware is used to inform design decisions and to verify that component temperature ratings are not exceeded (with margin).
Resources under this topic area are primarily software tools for finite element analysis (FEA), smallsat thermal analysis reports that include procedures and formulas, and book chapters that outline traditional approaches.
Best Practices and Lessons Learned
- When developing an FEA workflow, make sure to experiment with simplified models to understand the influence of various modeling options/parameters and to verify that the tool is behaving as expected. CAD embedded FEA software tools like SolidWorks Simulation provide streamlined workflows and enable quick design iteration. However, their “black box” interfaces can lead to significant modeling errors. Use documentation, vendor engineering support, and the testing mentioned above to ensure that your process produces accurate results.
- Exhaustive, traditional thermal analysis is expensive and time consuming. In many cases, limited analyses can be completed before flight hardware design and used to impose design guidelines. Using these guidelines will allow for significantly reduced thermal analysis on the completed design.
- Thermal interface modeling should include significant margin. Uneven or incomplete compression of thermal interface materials can lead to vacuum performance that is significantly worse than performance at ambient pressure.
Blake Moffitt et al.
This conference paper describes thermal modeling of a smallsat and correlation to thermal vacuum (TVAC) ... test data. While dated, it is a useful case study for smallsat developers. It includes a complete description of the inputs and methods for modeling, analysis, and correlation to test data.
SolidWorks Simulation is a suite of FEA tools integrated with the SolidWorks computer aided design (CAD) ... tools. This software can be used to complete all the most common structural analyses for smallsats and their components (e.g. modal, random vibration, shock response spectrum, sine, static, fatigue). SolidWorks Simulation can also be used to carry out static and transient thermal analyses. Its integration with a powerful CAD tool streamlines design iteration. However, it is not appropriate for solution of some complex (e.g. high strain-rate) models and its simplified interfaces and workflows mean that some effort is required to fully understand the settings and avoid FEA modeling errors.
This is a stand-alone FEA tool that can be used to complete all the most common structural analyses for ... smallsats and their components (e.g. modal, random vibration, shock response spectrum, sine, static, fatigue) along with less common, more complex analyses like acoustic analysis. Nastran can also be used to carry out static and transient thermal analyses. A stand-alone program like Nastran generally requires more experience to understand and use than a CAD-enabled FEA software tool (e.g. SolidWorks Simulation); however, it has more capabilities and provides a more detailed level of direct control and reporting of modeling parameters.
This page in the NASA Public Lessons Learned System describes the importance of establishing a "mandatory ... closed-loop system for detailed, independent, and timely technical reviews of all analyses performed in support of the reliability/design process." These reviews are important for detecting design defects.
This conference paper presents detailed thermal analysis and thermal environmental test planning for ... a cubesat. It's a good case-study and example report for smallsat thermal analysts and thermal test engineers. Inputs, assumptions, methods, and results are all presented in detail.
This conference paper presents detailed thermal design and analysis for a 12U cubesat. It's a useful ... case-study and example report for smallsat thermal analysis engineers. Inputs, assumptions, methods, and results are all presented in detail.
Derek Hengeveld et al.
This conference paper presents smallsat thermal design concepts "focused on high-efficiency, lightweight ... deployable radiating technologies" to enable exceptionally high power dissipation. Commercial thermal control components sized for small satellites are introduced. Figure 6 provides plots that can be used to size a smallsat radiator. Various spacecraft-level thermal designs for a notional 6U cubesat are presented and analyzed using Thermal Desktop. Section 4 provides a good, concise example of smallsat, spacecraft-level thermal analysis.
Casper Versteeg et al.
This conference paper presents a method for preliminary thermal analysis of smallsats that does not require ... expensive off-the-shelf software tools. It can be implemented in any common programming language (e.g. MATLAB or Python).
This masters thesis covers thermal design and thermal analysis for small satellites. It includes background ... on the physics of heat transfer, software tools for thermal modeling, thermal control hardware, and processes for thermal design and analysis. An example thermal analysis for a university small satellite is presented in detail. Appendix B provides optical properties for common surface finishes and coatings.
Thermal Desktop is a CAD-based suite of thermal engineering tools. It is one of the most common tools ... used for spacecraft-level thermal analysis. Users can develop 3D models in the CAD interface or import from other design tools. A built-in database of thermophysical properties allows the user to assign representative materials to bodies. Users can define dissipating components, thermal control devices, and environmental parameters. Thermal Desktop solves models using the integrated SINDA/FLUINT solver and includes an integrated plotting utility for analysis.
Solaria Thermal is a finite element analysis (FEA) software tool for thermal analysis. Built-in functionality ... allows users to generate 3D models for analysis, but users can also import 3D meshes from other programs (e.g. Gmsh). Solution, post-processing, and visualization tools are all included in this tool. Using the SolariaPCB add-on, users can import PCB artwork to create exceptionally detailed FEA models of electronics that include copper layers, vias, and EEE component thermal properties.
This page in the NASA Public Lessons Learned System provides a maximum recommended junction temperature ... for electronic components on spacecraft. Detailed motivation for this recommended maximum temperature is provided - including references.
This book provides practical methods for the design of electronics to survive severe thermal environments. ... The formulas and methods presented here can be used to develop spreadsheets or simple software tools for thermal analysis of electronics. Therefore, the modeling methods presented in this book can allow engineers to carry out thermal analysis of electronic subsystems without expensive and detailed, EEE-component-level FEA modeling.
George Sebestyen et al.
This book chapter, titled "Thermal Design" covers thermal design, analysis, and testing for LEO satellites. ... This includes background on the physics of heat transfer, thermal control hardware, and processes for thermal design, analysis, and testing. Note that this chapter is only 13 pages, and does not go into significant detail on any of the included topics.
This chapter titled "Mountings and Interfaces" is a comprehensive reference regarding the thermal design ... and analysis of interfaces for space applications. It includes design guidance, formulas for modeling thermal interfaces, surface roughness values for various production methods, and thermal interface material properties.
This chapter titled "Thermal Design Analysis" is a comprehensive reference for thermal analysis of spacecraft ... hardware. It includes formulas, modeling methods, and software tools. The material is presented in the context of traditional space missions. A thermal analysis case study for an imaging instrument is provided near the middle of this chapter.