Keeping spacecraft in orbit at an operational temperature is a challenging problem. Spacecraft need to deal with the very cold background temperature of space, while also managing high thermal loads from internal components, earth’s albedo, and solar radiation. Solving this problem is made more complex by the various orbital maneuvers a spacecraft can take while in orbit.
Thermal Desktop is a system level thermal analysis tool with multiple features that help engineers solve the complex challenge of evaluating the thermal performance of spacecraft. It was developed by CR Tech for NASA's Johnson Space Center and has played roles in evaluating the performance of the Mars Ingenuity helicopter and the James Webb Space Telescope.
Source: Ansys
Thermal Desktop is a system level thermal analysis tool. We can import CAD files to use within Thermal Desktop. We can also build the geometry using Thermal Desktop’s Finite Difference primitive shapes. This results in a simpler model that can more efficiently solve radiation problems.
Source: CR Tech
Thermal Desktop has the ability to define various material properties and coatings, including independent emissivity and absorption values. These parameters are important to accurately represent radiation.
Contactors can be used to represent surface contacts and their contact resistances. Conductors are used to represent thermal connections between bodies without needing to model an entirely new body.
Due to the vacuum of space, radiation and conduction are the primary drivers of heat transfer in spacecraft. We can define heaters to represent thermal loads from internal components. Thermal desktop also allows users to efficiently solve surface to surface radiation problems, as well as evaluate solar loads.
We can evaluate solar loading as the spacecraft orbits various celestial bodies, with varying orbital inclinations. We can also look at what orbital path the spacecraft takes, and what orientation the spacecraft is in.
In addition, we can define articulators to change the geometry of the spacecraft as it goes through its orbit. This is useful to ensure that solar panels are oriented in the correct direction, or to represent hatches, lids, or other systems changing their orientation. We can also use more detailed orbital models to represent albedo or free molecular heating. In the below example, the satellite stays pointed at the earth while the solar panel tracks the sun. The purple cone indicates the shadow cast by the earth.
Thermal management is a critical and complex aspect of spacecraft design. Thermal Desktop provides thermal engineers with the tools they need to evaluate their designs and drive design choices.