LionSat Thermal Subsystem Team Members: Nathan Hermanson Adam McDonald Joel Thakker
LionSat – Thermal Subsystem Objective: maintain temperature within the acceptable operating and non-operating ranges during the entire mission life of the program. Current design: non- insulated cylindrical Aluminum shell. Allows for a good first approximation Operating and Storage Temperatures Overview
Problems and Solutions Familiarization to the program Software Issues - SINDA: Code was outdated and not user friendly. - Thermal Desktop: Licenses not available - Working CAD model of LionSat with dimensions not available. Solutions: - Downloaded trial version of Thermal Desktop - Created our own 3D model using Thermal Desktop; inner diameter of 18.5 inches and height of inches.
Progress Made in Fall 2003 Single Node Analysis - Code written in MATLAB - Considered only two cases in orbit - Temperature ranges are reasonable - Equivalent C++ code idea dropped Multi – Node Analysis - Using Thermal Desktop only - Gives a good first approximation for heat flux across the satellite at varying positions in orbit
Input Format – AutoCAD drawings - Direct input can used in the trial version i.e. AutoCAD is not needed - SolidWorks files can be imported by AutoCAD using the plug-in ExchangeWorks. This allows compatibility with the drawings done by the structures subsystem.
Uses finite analysis to model a thermal environment. Orbital parameters including altitude, inclination, and spin can be defined; and the thermal results due to earthshine, and solar radiation measured. Heat sources and other radiation sources can be defined, and the conductivity throughout the satellite can be observed. Material properties can be defined and easily changed.
Thermal Desktop Material Properties
Top left: going into earth shadow; Top right: Complete Shadow; Bottom left: going into full sun; Bottom Right: Sun facing
Actual design of satellite exterior Note: Few nodes on end caps. This data can be used to determine the hot spots on the satellite where insulation may need to be applied.
Things to Prepare for the SDR Each team was asked for any and all recent items in regard to five categories: Presentation slidesPresentation slides Preliminary Subsystem DrawingsPreliminary Subsystem Drawings Subsystem Test plansSubsystem Test plans Materials ListMaterials List Prototype HardwarePrototype Hardware
SDR (cont.) The slides have been started, currently working on revising them. As the thermal subsystem is anticipated to be a fully passive one, we do not have any preliminary drawings Materials list will not be completed until the multi-node analysis is completed
Work for Next Semester Ensure Thermal Desktop is available for LionSat Thermal Subsystem Finish simple multi-node analysis Develop a thermal budget Begin incorporating all other subsystems into model Consider thermal vacuum testing
Questions?