UV irradiation effect on the electrical properties of ZnO thermal control coating pigment
ZnO coating pigment for spacecraft thermal control, examining UV irradiation effects on electrical properties
Kulshreshtha, A. P.↗
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Use of Thermal Reradiative Effects in Spacecraft Attitude Control
Thermal reradiation effects on oscillation damping for spacecraft attitude control
VIBRATION DAMPING↗
Large Deployable Reflector (LDR) thermal characteristics
The thermal support group, which is part of the lightweight composite reflector panel program, developed thermal test and analysis evaluation tools necessary to support the integrated interdisciplinary analysis (IIDA) capability. A detailed thermal mathematical model and a simplified spacecraft thermal math model were written. These models determine the orbital temperature level and variation, and the thermally induced gradients through and across a panel, for inclusion in the IIDA.
Miyake, R. N.↗
Apollo experience report: Manned thermal-vacuum testing of spacecraft
Manned thermal-vacuum tests of the Apollo spacecraft presented many first-time problems in the areas of test philosophy, operational concepts, and program implementation. The rationale used to resolve these problems is explained and examined critically in view of actual experience. The series of 12 tests involving 1517 hours of chamber operating time resulted in the disclosure of numerous equipment and procedural deficiencies of significance to the flight mission. Test experience and results in view of subsequent flight experience confirmed that thermal-vacuum testing of integrated manned spacecraft provides a feasible, cost-effective, and safe technique with which to obtain maximum confidence in spacecraft flight worthiness early in the program.
Mclane, J. C., Jr.↗
Effects of decontamination, sterilization, and thermal vacuum on spacecraft polymeric products
Effects of thermal sterilization, long term thermal vacuum exposure, and decontamination on spacecraft polymeric products
Roper, W. D.↗
Studies of ultraviolet irradiation effects in ZnO-type thermal control coating pigments.
UV irradiation effects on ZnO spacecraft thermal control coating pigments, discussing photo-Hall, luminescence and electron paramagnetic resonance measurements
Hayes, J. D.↗
Proceedings of conference on Active Temperature Control
Conference on active temperature control for spacecraft - thermal radiation
SPACECRAFT ENVIRONMENT↗
Conceptual mechanization studies for a horizon definition spacecraft structures and thermal subsystem
Conceptual mechanization for horizon definition spacecraft structures and thermal subsystem - spin-stabilized, hexagonal cylinder for launch of two-stage Improved Delta /DSV-3N/
SPACECRAFT CONFIGURATION↗
The thermal control challenge of the Mars observer spacecraft
The thermal control subsystem for the Mars Observer spacecraft has been synthesized from hardware currently in use on earth-orbiting satellites. Heat input to the spacecraft from environmental and internal sources varies widely throughout the mission, and system requirements, such as accommodation of payload instrument fields-of-view and minimization of weight and power, limit the sizes and locations of thermal control elements. Subsystem components are primarily passive, although heaters and louvers provide augmented control where required. Spacecraft-level finite difference thermal models have shown that all component temperature requirements are met with margin.
Braun, C. E.↗
Emittance characterization of thermal control paints, coatings and surfaces using a calorimetric technique
Thermal control surfaces are used in every spacecraft thermal management system to dissipate heat through radiant heat transfer. This paper describes the thermal performance of several thermal control paints, coatings, and surfaces, as characterized by a calorimetric vacuum emissometer. The emissometer is designed to measure the functional emittance of a surface based on heat transfer from an underlying substrate to the surface and from the surface or near surface to a surrounding cold wall. Emittance measurements were made between 200 and 350 K. Polished aluminum, used here as a standard, was found to have a total hemispherical emittance of 0.06, as expected. A velvet black paint, also used here as a standard, was found to have an emittance of 0.94 at room temperature. Other surfaces of interest included a polyurethane-based black paint designated Z-306, a highly polished 316L stainless steel, and an atomic oxygen beam-textured carbon-carbon composite.
Jaworske, Donald A.↗
Model-Based Thermal System Design Optimization for the James Webb Space Telescope
Spacecraft thermal model validation is normally performed by comparing model predictions with thermal test data and reducing their discrepancies to meet the mission requirements. Based on thermal engineering expertise, the model input parameters are adjusted to tune the model output response to the test data. The end result is not guaranteed to be the best solution in terms of reduced discrepancy and the process requires months to complete. A model-based methodology was developed to perform the validation process in a fully automated fashion and provide mathematical bases to the search for the optimal parameter set that minimizes the discrepancies between model and data. The methodology was successfully applied to several thermal subsystems of the James Webb Space Telescope (JWST). Global or quasiglobal optimal solutions were found and the total execution time of the model validation process was reduced to about two weeks. The model sensitivities to the parameters, which are required to solve the optimization problem, can be calculated automatically before the test begins and provide a library for sensitivity studies. This methodology represents a crucial commodity when testing complex, large-scale systems under time and budget constraints. Here, results for the JWST Core thermal system will be presented in detail.
Cataldo, Giuseppe↗
Psyche Magnetometer Engineering Model Test and Thermal Model Correlation to Validate Operational Thermal Requirement
Psyche Fluxgate Magnetometer candidate fabricated by UCLA has a critical temperature gradient requirement inside the magnetometer sensor head. Since the temperature gradient requirement is a driving factor for the magnetometer operation and science data collection at 16 Psyche, it is critical to validate and verify this requirement via modeling and test. In this work, a thermal vacuum test was completed for Psyche flight-like magnetometer engineering model. Flight-like environments were simulated for a hot operational case (after launch), a cold survival case (cruise), and two cold operational cases to characterize thermal performance of the instrument. An additional, non-flight, steady-state test case was completed to better correlate the magnetometer thermal model. During the test, sensitive Cernox temperature sensors with accuracy of ±0.1°C were used to precisely characterize the temperature gradient and correlate the model to the best accuracy. Collected test data indicated power consumption of 28% lower than predicted. The temperature gradient measured met the expected value and the requirement. Test data indicated the magnetometer also met the AFTs in relevant hot and cold environments. Test Results were used to correlate the thermal model. The correlated thermal model will be integrated to the spacecraft thermal model to predict magnetometer thermal performance while collecting science data in Psyche orbits.
Caron, Ryan↗
Conductive White Thermal Control Paint for Spacecraft - Part 2
Thermal control paints were evaluated for use as electrically conductive white thermal control coatings on the saturn-bound cassini spacecraft.
silicate↗
Thermal testing by internal IR heating of the FEP module
A spacecraft module, to be integrated with the FLTSATCOM spacecraft, was tested in a simulated orbit environment separate from the host spacecraft. Thermal vacuum testing of the module was accomplished using internal IR heating rather than conventional external heat sources. For this configuration, the technique produced boundary conditions expected for flight to enable verification of system performance and thermal design details.
Nathanson, D. M.↗
Surface Models of Mars (1975)
Data derived from Mariners 6, 7, and 9, Russian Mars probes, and photographic and radar observations conducted from earth are used to develop engineering models of Martian surface properties. These models are used in mission planning and in the design of landing and exploration vehicles. Optical models needed in the design of camera systems, dielectric properties needed in the design of radar systems, and thermal properties needed in the design of the spacecraft thermal control system are included.
Source record↗
Innovative method for the thermal cycling of large spacecraft systems
The use of low cost, off the shelf prefabricated enclosures for spacecraft system thermal cycling applications was indicated. The enclosures are erected in the satellite integration areas without disturbing the test article, electrical test set, or RF interfaces. They are assembled by metal clad, modular urethane panels. These panels are self supporting, and are locked and sealed to each other on assembly. Penetrations for interconnecting cables, coaxial and waveguide services; and temperature conditioning inlet and outlet ducts are easily incorporated where required. The facility and its advantages and intrinsic benefits are described.
Steimer, C. H.↗
Two phase capillary pumped heat transfer in the Instrument Thermal Test Bed
An experimental study of the thermal performance of two evaporators installed in the Instrument Thermal Test Bed (ITTB) was conducted. The ITTB was operated as a capillary pumped loop (CPL) with a transport length of approximately 12 meters. Empirical determinations of a general start up procedure, overall heat transfer coefficient, and minimum operating power were accomplished for each evaporator. Additionally, a detailed thermal model was developed for the High Power Spacecraft Thermal Management (HPSTM) evaporator and validated.
Didion, Jeffrey R.↗
Topex Microwave Radiometer thermal control - Post-system-test modifications and on-orbit performance
The Topex Microwave Radiometer has had an excellent thermal performance since launch. The instrument, however, went through a hardware modification right before launch to correct for a thermal design inadequacy that was uncovered during the spacecraft thermal vacuum test. This paper reports on how the initially obscure problem was tracked down, and how the thermal models were revised, validated, and utilized to investigate the solution options and guide the hardware modification decisions. Details related to test data interpretation, analytical uncertainties, and model-prediction vs. test-data correlation, are documented. Instrument/spacecraft interface issues, where the problem originated and where in general pitfalls abound, are dealt with specifically. Finally, on-orbit thermal performance data are presented, which exhibit good agreement with flight predictions, and lessons learned are discussed.
Lin, Edward I.↗