Session
Poster Session II
Event Website
https://www.smallsat.org/index
Abstract
The interest in the use of CubeSat and small satellites for commercial, government and military applications continues to grow. Particularly in Low Earth Orbit, the successful deployment of commercial electronics has allowed dramatic reductions in cost and dramatic improvements in performance. These benefits leverage the R&D and production infrastructure of terrestrial electronics companies that dwarf the traditional space supply base. However, questions remain on the specific levels of reliability that can be achieved using hardware that was designed and tested for use in a very different environment compared to traditional space components that are designed for and tested to environmental levels seen within the launch and space environments.
CubeSats and small satellites face thermal management challenges due to the limited available surface area for radiative cooling and their small heat capacity. Compared to typical terrestrial operating environments, these factors can lead to components running at higher average temperatures than would be preferred and experiencing a relatively wide range of temperatures due to cycling orbital boundary conditions. Both high temperature and wide cycling range have been identified as key contributors to space component failure in the past. With ever more ambitious payloads and larger power systems enabled by technologies such as CubeSat solar arrays and electric propulsion, the need for better thermal management will grow.
This paper presents the analysis, benefits and initial testing of a two-phase FlexCool heat strap, under development by i2C Solutions for space applications. The FlexCool heat strap is a thin, flexible, two-phase heat spreader, made of thin copper foils as casing layers and copper woven messes as wicking layers. The FlexCool is a highly efficient thermal management solution, with low volume and weight, and high thermal performance, which can be seamlessly integrated in CubeSats and small satellites. Spacecraft-level thermal models of representative 1U and 3U CubeSat geometries have been developed, including prototypical electronic boards, thermally connected to external body radiators through traditional poor thermal paths as well as through FlexCool thermal straps. Hot and cold bounding orbits, were used for analyzing the thermal response of the electronic components. The models produced orbital temperature profiles of electronic components and were used for parametric analyses of the effect of different design factors. In particular, the effect of providing a thermal conductance to the electronic components was studied, and the benefits of a two-phase heat strap over traditional copper straps were identified.
Results demonstrate that a FlexCool heat strap can provide a similar heat transfer capability with 10 times lower mass and 3 times lower volume than current copper thermal straps. Using standard reliability models for EEE components, an assessment will be made on the potential reliability improvements to be gained from adopting FlexCool to allow electronics to run in more benign thermal environments.
Using a one-dimensional test rig, experimental results obtained during the development of the FlexCool thermal strap demonstrated an effective thermal conductivity that is up to five times the thermal conductivity of copper, in agreement with theoretical models.
Included in
Enhancing CubeSat and Small Satellite Reliability through Improved Thermal Management
The interest in the use of CubeSat and small satellites for commercial, government and military applications continues to grow. Particularly in Low Earth Orbit, the successful deployment of commercial electronics has allowed dramatic reductions in cost and dramatic improvements in performance. These benefits leverage the R&D and production infrastructure of terrestrial electronics companies that dwarf the traditional space supply base. However, questions remain on the specific levels of reliability that can be achieved using hardware that was designed and tested for use in a very different environment compared to traditional space components that are designed for and tested to environmental levels seen within the launch and space environments.
CubeSats and small satellites face thermal management challenges due to the limited available surface area for radiative cooling and their small heat capacity. Compared to typical terrestrial operating environments, these factors can lead to components running at higher average temperatures than would be preferred and experiencing a relatively wide range of temperatures due to cycling orbital boundary conditions. Both high temperature and wide cycling range have been identified as key contributors to space component failure in the past. With ever more ambitious payloads and larger power systems enabled by technologies such as CubeSat solar arrays and electric propulsion, the need for better thermal management will grow.
This paper presents the analysis, benefits and initial testing of a two-phase FlexCool heat strap, under development by i2C Solutions for space applications. The FlexCool heat strap is a thin, flexible, two-phase heat spreader, made of thin copper foils as casing layers and copper woven messes as wicking layers. The FlexCool is a highly efficient thermal management solution, with low volume and weight, and high thermal performance, which can be seamlessly integrated in CubeSats and small satellites. Spacecraft-level thermal models of representative 1U and 3U CubeSat geometries have been developed, including prototypical electronic boards, thermally connected to external body radiators through traditional poor thermal paths as well as through FlexCool thermal straps. Hot and cold bounding orbits, were used for analyzing the thermal response of the electronic components. The models produced orbital temperature profiles of electronic components and were used for parametric analyses of the effect of different design factors. In particular, the effect of providing a thermal conductance to the electronic components was studied, and the benefits of a two-phase heat strap over traditional copper straps were identified.
Results demonstrate that a FlexCool heat strap can provide a similar heat transfer capability with 10 times lower mass and 3 times lower volume than current copper thermal straps. Using standard reliability models for EEE components, an assessment will be made on the potential reliability improvements to be gained from adopting FlexCool to allow electronics to run in more benign thermal environments.
Using a one-dimensional test rig, experimental results obtained during the development of the FlexCool thermal strap demonstrated an effective thermal conductivity that is up to five times the thermal conductivity of copper, in agreement with theoretical models.
https://digitalcommons.usu.edu/smallsat/2016/Poster2/9
