Editor: Analysis of Thermal Profiles
Description
Thermal profiles play a pivotal role in the comprehensive analysis of a spacecraft's lifespan. This significance arises from the considerable temperature fluctuations resulting from the spacecraft's orientation relative to the sun. To streamline thermal analysis, a lookup table is employed for each component. These tables are user-generated, with the true anomaly of the spacecraft or simulation time serving as the covariate. Notably, reaction wheels feature an extended thermal lookup capability, enabling them to retrieve thermal information based on their rotational speeds, further enhancing the precision of temperature predictions over time and true anomaly.
Generating Lookup Tables
The thermal profiles rely on lookup tables, anticipated to be in CSV format. In these tables, the initial value corresponds to the true anomaly of the spacecraft in radians, followed by temperatures assigned to each thermal component at that specific true anomaly within the orbit. Time, a crucial parameter, can also be incorporated into these tables, allowing users to account for temporal variations and enhance the accuracy of thermal predictions throughout the spacecraft's orbital trajectory. Here's an illustrative example lookup table for thermal analysis.
True Anomaly,Spacecraft,SolarPanel,ReactionWheels,Computer
0,351.5195294,484.2607406,513.1392357,508.520963
0.01,351.7195261,484.4107381,329.6174577,547.3239825
0.02,351.9195027,484.5607206,443.8278111,587.7156144
0.03,352.1194394,484.7106731,474.6814655,455.109166
: : : : :
: : : : :
6.28,351.4558234,484.2129611,453.5158443,457.3010831
6.283185307,351.5195294,484.2607406,513.1392357,508.520963
Note
The lookup tables generated using the true anomaly or simulation time would be specific to a certain scenario for a given date time. The thermal analysis is conducted for visualization purposes and does not do any thermal solving.
Connecting the Lookup table to the components
For each thermal component of a spacecraft, a Thermal Properties structure needs to be created and set under the component's Thermal Properties, as shown below.
When making the Thermal Properties struct, the thermal node ref refers to the column of the csv to which the components data could be found, where column 0 would be the true anomaly or simulation time and column 1 would be the ‘first’ dependent variable column. The filename refers to the name of the csv containing the lookup table and the analysis type should be turned to Enable for the temperatures to be updated over time.
Note
The file must be placed somewhere in the project with a unique name. If the file cannot be found, an error will be thrown with invalid data.
The reaction wheels can switch the analysis type to self where the csv would then have to be loaded up with wheel speed in rad/s as the independent variable.
Static Predefined Temperatures
Static temperatures could be set up for components using the Set Temperature function for physical components, as shown below. This works for any component and does not require a lookup table. The temperature can be set throughout the simulation and custom blueprint logic can manipulate the data over time.
Analysis of Temperatures
Temperatures of each component could then be plotted for analysis. This is shown in the scenario demo and the screenshot below.
