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The Wide Field Camera 3 (WFC3) instrument has undergone two complete thermal vacuum tests (TV1 and TV2), during which valuable lessons were learned regarding test configuration, test execution, model capabilities, and modeling practices. The very complex thermal design of WFC3 produced a number of challenging aspects to ground testing with numerous ThermoElectric Coolers and heat pipes, not all of which were functional. Lessons learned during TV1 resulted in significant upgrades to the model capabilities and a change in the test environment approach for TV2. These upgrades proved invaluable during TV2 when pre-test modeling assumptions proved to be false. Each of the lessons learned relate to one of two following broad statements: 1. Ensure the design can be tested and that the effect of non-flight like conditions is well understood, particularly with respect to non passive devices (TECs, Heat Pipes, etc) 2.

Metop (METeorological OPerational satellite) is a series of three satellites designed to monitor the climate and improve weather forecasting. This paper describes the thermal analysis, thermal testing performed, and relevant lessons learned. For the thermal analysis campaigns it focuses on: exchange and correlation of reduced thermal mathematical models established in various software formats sizes and content of the models, in particular automatic generation of reduced models from the detailed models uncertainties definitions of thermal interfaces The lessons learned from the thermal testing campaigns apply to: selection of test environment, using solar simulation and/or infra-red techniques selection of test cases based on thermal design driving parameters and/or test chamber capabilities adequate instrumentation (i.e. thermocouples, test heaters) for all critical components (un)expected events e.g.

The Spacecraft Radiative Thermal Model Exchange System is a technology developed for the bi-directional exchange of spacecraft radiative thermal models via the TMG thermal software package. It provides a means for quickly and accurately transferring models between TMG and theree of the major thermal radiation codes used in the spacecraft industry, particularly the ESARAD and Thermica packages, which are widely used by contractors to the European Space Agency, and the TSS code which is prevalent in the United States space industry. In order to reconcile element-based and primitives-based modeling approaches, this system includes an interactive primitives-based modeling system, enabling users to construct, import, and manipulate primitives-based radiation models in TMG.

A SINDA subroutine has been developed to predict the power generated by a Thermo-Electric Cooler (TEC). A TEC can be described analytically by relations between four parameters: cold side temperature, hot side temperature, parasitic heat load, and electrical power. The subroutine requires the user to input the hot side and cold side temperatures, the corresponding parasitic heat load, and coefficients describing the vendor performance curves. The subroutine then utilizes an iterative solution scheme and vendor TEC performance curves for specific hardware to determine the current (and consequently the TEC power) that satisfies these requirements. This paper provides an in-depth discussion of the algorithm employed in the subroutine, implementation of the subroutine in the HST Wide Field Camera 3 thermal model, and the evaluation of the subroutine performance against actual test/correlation data.

LISA (Laser Interferometer Space Antenna) is a constellation mission designed to detect gravitational waves using laser interferometry by measuring the laser path length between two free floating proof masses in opposing spacecraft separated by ∼5 million kilometers. As such, the LISA mission requires unprecedented thermal stability and, due to difficulties with ground testing, relies heavily on analysis. A Finite Element Model (FEM) was selected as the baseline modeling technique, using an identical mesh for each phase of STOPG (Structural-Thermal-Optics-Performance-Gravity) analyses. Two thermal codes were evaluated (TMG® and ThermalDesktop®) that both interfaced well with FEM software. TMG calculates element mid-side and centroid temperatures and then interpolates/extrapolates to derive nodal temperatures, which could introduce potential errors.

ThermPlot Pro is a Windows based, post-processing tool that interfaces with standard output files from many of the industry’s leading finite difference thermal modeling tools, including: SINDA/FLUINT, SINDA/G, ESATAN, TMG, TAK2000, and TSS. ThermPlot Pro takes the standard output from these tools and imports the data into a user created Microsoft Excel® workbook. From the ThermPlot interface, a user may define Tables or Plots of relevant data, group nodes together for simplification, create specialized parameters, or evaluate heat flow throughout a model using a specialized, interactive HeatMap workbook. Tabular data may include minimums, maximums, averages, or any selected timestep. It also includes the option to add user-defined limits to the tables and highlight data that is out of limit conditions. Plotted data allows the user full control over series properties (color, linetype, marker, etc) as well as control over the axes properties (minimum, maximum, major division, etc.)