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Thermal Balance

Scope and Description

This topic page covers thermal balance testing of smallsats. Thermal balance is typically performed as part of the thermal vacuum test, and its goal is to verify the performance of the thermal design and survival of the spacecraft under some discrete set of configurations. Each of these test configurations will have an associated thermal environment and operational state of the spacecraft. For example, thermal balance testing may include (1) a worst-case/hot configuration which maximizes heating of the exterior of the spacecraft and dissipation from spacecraft electronics and (2) a worst-case/cold configuration with no solar heating (i.e., eclipse environment) and a minimum dissipation mode of spacecraft operation. The spacecraft is allowed to dwell at each configuration to reach steady-state. Temperature measurements and then a post-dwell functional test are used to verify survival and thermal performance of the spacecraft. In addition, temperature data is used for validation and refinement of analytical thermal models. This testing can be particularly important for smallsats, as smallsat teams often do not have access to the tools, expertise, or budget necessary to complete accurate, high-fidelity thermal analyses.

Resources under this topic area are primarily traditional standards that include thermal balance requirements and white papers and articles that provide case studies or guidance specifically for thermal balance testing of smallsats.

Best Practices and Lessons Learned

Last Updated:

Nov. 10, 2021

Consider redundancy for critical, yet cheap, electronic components such as mass memory devices (e.g. SD Cards) that are less resilient to the radiation environment.

Last Updated:

Nov. 10, 2021

Consider redundancy for critical, yet cheap, electronic components such as mass memory devices (e.g. SD Cards) that are less resilient to the radiation environment.

Last Updated:

Nov. 1, 2021

Carefully design the spacecraft physical configuration and heating to emulate the on-orbit heat transfer to your spacecraft. Account for or remove deployables and determine whether adjustments to the environment are necessary to account for end-of-life thermo-optical properties of the external surfaces.

Last Updated:

Nov. 1, 2021

Always bond thermistors to the hardware under test using a robust, thermally conductive bonding compound. Test are often delayed or invalidated due to improperly attached test instrumentation which becomes detached.

Last Updated:

Nov. 1, 2021

Thermistor wires can create thermal bridges between components. Take special care when routing and affixing test instrumentation to avoid influencing results.

Resources

Last Updated: Nov. 11, 2021

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.

Last Updated: June 16, 2021

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.

Last Updated: Aug. 5, 2020

This chapter titled "Thermal Testing" is a comprehensive reference regarding thermal testing of space ... flight hardware. The tests covered are thermal cycling (ambient pressure), thermal vacuum, thermal balance, and burn-in. It includes a description of the elements and stages of the traditional approach, environments, margins, requirements, and required equipment/facilitates.

Last Updated: Nov. 10, 2021

This ECSS standard details specific standards for ground testing of space flight hardware. The testing ... covered includes mechanical, structural, thermal, electrical, and RF - among others.

Last Updated: Oct. 19, 2021

This conference paper documents environmental testing performed on a 120kg university smallsat. It covers ... EMC testing, vibration testing, and thermal/vacuum testing. This resource provides valuable information to inform environmental testing of other smallsats, including theoretical background, test conditions, photos, diagrams, and experimental data.

Last Updated: June 16, 2021

Thermal-vacuum testing is critical to ensuring satellite reliability and survivability. Unfortunately, ... many thermal-vacuum chambers are much larger than necessary for small satellites, resulting in an unnecessary cost burden for developers. This paper seeks to outline the methodology for developing thermal-vacuum chambers for testing small satellites.

Last Updated: Nov. 11, 2021

This resource provides a detailed review of the Miniature X-ray Solar Spectrometer (MinXSS) 3U CubeSat ... and the testing performed on the spacecraft's science instruments. Section III of the article details the thermal vacuum balance (TVAC) and thermal balance (TBAL) testing that was performed in preparation for its May 16, 2016 launch.

This article provides an overview of thermal balance testing on microsatellites. Due to their small size, ... microsatellites are more susceptible to Earth IR radiation compared to the more traditional larger satellites. Test procedures and results for the thermal balance testing in various environments and under multiple IR radiation levels are provided.

This article discusses the thermal balancing criteria and results for U.S. Air Force space programs. ... It details two thermal balance test criteria: thermal balance stabilization, and thermal model coorelation.

Last Updated: Oct. 16, 2021

This book provides an overview of space missions and how spacecraft hardware is affected by the space ... environment. Section 20.5 Thermal Balance Tests, specifically discusses standard processes and procedures for thermal balance testing of spacecraft hardware.

Last Updated: Oct. 19, 2021

In this report, risk perspectives of Class C and Class D (moderate and high-risk) programs are discussed ... and aligned with mission success expectations. Thermal test recommendations to achieve desired test effectiveness goals are provided along with the associated risks resulting from tailored thermal test parameters. Beyond providing cost-effective thermal test requirements applicable to many smallsat missions, this document provides extremely valuable context and data to support its recommendations and enable a detailed understanding of each test.

Last Updated: Oct. 18, 2021

This handbook provides in-depth guidance on testing of space vehicles. This is a dated but comprehensive ... source of space hardware test environments and processes that could be used to inform test planning and execution for smallsat projects. This section covers thermal balance testing of space vehicles.