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Radarsat is a Canadian remote sensing satellite designed to gather earth resource data from a low earth orbit. The spacecraft consists of four major entities: the payload module, the bus module, the SAR antenna and the solar arrays.

The ARTEMIS (Advanced Relay and TEchnology MISsion) satellite represents the first element of the Data Relay and Technology Mission Programme (DRTM) developed for the European Space Agency by Alenia Aerospazio (Italy) as the prime contractor. Although using conventional design features and limited mass, power, telemetry and tele-command budgets, the thermal control of the satellite matches the demands dictated by the peculiarities of the ARTEMIS mission such as the significant overall dissipation, the wide spectrum of payload operational scenarios and the relatively unbalanced distribution of payload equipment dictated by system and payload performance considerations. This paper describes the thermal control design solutions with special regard to consideration on ground testability of the system; the analytical approach to predict on-orbit thermal response; the policy adopted in terms of margins and analytical uncertainties.

The Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) spacecraft is the first science mission in the Solar Terrestrial Probe program sponsored by the NASA Office of Space Sciences and is being developed by the Johns Hopkins University, Applied Physics Laboratory (APL). ...The TIMED spacecraft is a three axis stabilized, nadir pointing, low earth orbit scientific satellite with one side of the spacecraft always pointing away from the sun. ...The TIMED spacecraft is a three axis stabilized, nadir pointing, low earth orbit scientific satellite with one side of the spacecraft always pointing away from the sun. The instruments' fields of view (FOV), pointing accuracy, jitter requirements, anti-sun pointing of one spacecraft side, and sun angle variations during the year place severe limitations on the design configuration of the solar array.

The effect of the device upon spacecraft thermal balance, mechanical integrity and configuration, mission interference, and electrical compatibility are explored.

Experience with free-flying space payloads in the current era of reduced budgets has led to a continuing need for an easier-to-use and more cost-effective capability for spacecraft thermal analyses. Preliminary thermal design of the MSX spacecraft has been developed using an 80386-based MS-DOS microcomputer. ...These programs provide both an interactive geometry editor and a graphical representation of the current spacecraft geometry. The output of VIEWI is converted to a SSPTA2 geometry input file. SSPTA, a software package that simplifies the procedures for conducting sophisticated thermal analyses of orbiting payloads, consists of CONSHAD, a view factor calculation program, SCRIPTF, a radiation conductance calculation program, ORBITAL, a satellite orbital heat flux program, and ABSORB, a program to calculate absorbed power.

The software package for computerized modeling of thermal regimes of a spacecraft (S/C) provided with passive and active means of temperature control, under conditions of orbital flight mission and at thermo-vacuum testing conditions, is represented.

Analysis has been performed for the overall spacecraft, the subsystems and some selected units. The thermal control system of the RADARSAT-1 has been examined for cases of both normal orbital conditions and abnormal thermal environments and operations.

Using the presently available technologies in the fiber composite rotors and in magnetic bearings, it is feasible to design the flywheel energy storage to replace the battery in the spacecraft power system. The potential benefits are reductions in weight, size and cost. The fundamental design considerations in designing the photovoltaic/flywheel power system are investigated in this paper.

This paper evaluates four proposals for reducing the costs of spacecraft and other payloads. It concludes that: (1) Using a standard bus, if available, could save up to two-thirds the cost of using a customized bus. (2) Payloads could cost less if allowed to be heavier.

Also described are the primary mission objective, the spacecraft configuration, requirements and design drivers, mission environments, and design parameters.

ALTAN (ALenia Thermal ANalyser) is a tool developed in Alenia Spazio, for the thermal simulation of satellites. Distinctive features of ALTAN are the description of the system in terms of thermal objects that can be considered as high level primitives, the accurate modelling of the energy sources (planets and sun) and of the optical properties, the integration in a single tool of the steps of radiative, conductive and thermal calculations and of the post-process of the results. An example of ALTAN application is given for Bepi-Colombo mission to Mercury, in particular the modelling of the highly variable planet temperature and the directional optical properties of the planet surface.

A review is presented of the mission requirements and other considerations which led to the successful development of fully passive satellite orientation techniques at the Applied Physics Laboratory, The Johns Hopkins University. Proven methods of magnetic and gravity-gradient attitude control are briefly described, and their utility in various applications is discussed. Some refinements and extensions of these techniques are examined in relation to projected missions, and some areas of profitable future development are outlined.

Several areas for improvement in the thermal and mechanical properties of the passive thermal control optical solar reflectors (OSRs) have been identified and discussed in a previous paper (1). These include the use of specialised optical coatings to optimise the emittance and absorptance of OSRs and also chemical treatments to provide greater resistance to handling and better conductivity where necessary. Each of the proposed techniques have been demonstrated and the most promising have been incorporated into development programmes leading to production. In parallel with this activity, examination of aspects of the whole passive thermal control system, in terms of optimal construction and assembly, and thermal and conductive properties is expected to commence shortly. It is anticipated that these will result in the specification and use of optimal thermal control systems for future satellites.

A passive thermal control system (TCS) augmented with manual and auto heaters are provided. The spacecraft completed four years of operation since 28th Dec'95. The TCS of the spacecraft has been very good. ...Temperature variation of the spacecraft is presented and discussed here. A nominal rise in temperature of the spacecraft observed is found to fit linear equation, and the same could be used to predict a conservative value of the temperature for the next few years. ...IRS-1C spacecraft is the most advanced civilian remote sensing satellite built in India with a steering panchromatic camera having a ground resolution of 5.8 m.

A design study of pumped two-phase and capillary-pumped thermal control systems (TCS) was conducted on a typical, advanced earth-orbiting spacecraft (AEOS). NASA's Upper Atmosphere Research Satellite (UARS) size and baseline design were chosen as the configuration for AEOS; however, the power requirements were increased and the allowable temperature range was decreased to represent the requirements of a more advanced spacecraft. ...NASA's Upper Atmosphere Research Satellite (UARS) size and baseline design were chosen as the configuration for AEOS; however, the power requirements were increased and the allowable temperature range was decreased to represent the requirements of a more advanced spacecraft. For peak-power dissipations of 1 or 2 kW, the capillary-pumped system was lightest. ...In addition to the weight advantage, the more nearly isothermal spacecraft obtainable with the two-phase system permits less compensation for thermal distortion; a simpler, less costly structure results.

The most, often utilized method of thermal design verification for past and current types of spacecraft has been by Solar Thermal Vacuum (STV) tests at system level. This approach, however, will require fundamental modifications for future large and complex spacecraft, three types of which are defined; a large communication satellite, a modular earth observation satellite and a large infrared telescope, all exceeding the capabilities of existing STV test facilities. ...This approach, however, will require fundamental modifications for future large and complex spacecraft, three types of which are defined; a large communication satellite, a modular earth observation satellite and a large infrared telescope, all exceeding the capabilities of existing STV test facilities. ...Alternative test methods - STV testing in parts, infrared radiation tests, thermal canister method, skin heater application - are also discussed with regard to their advantages and disadvantages of applying them to the large types of spacecraft. The thermal design considerations to be regarded and the critical parameters to be verified by test are highlighted, in order to enable the alternative verification test concept at an acceptable level of confidence.

Not only the detectors are cooled, but also major subsystems and systems of the spacecraft’s. The Centre Spatial de Liège (CSL) is involved in the testing of several parts of the spacecraft’s, starting from optical tests on the mirrors or on the telescopes, going on with cryogenic vibration testing of scientific focal plane instruments, ending with the full Planck spacecraft testing. ...The Centre Spatial de Liège (CSL) is involved in the testing of several parts of the spacecraft’s, starting from optical tests on the mirrors or on the telescopes, going on with cryogenic vibration testing of scientific focal plane instruments, ending with the full Planck spacecraft testing. ...The Centre Spatial de Liège (CSL) is involved in the testing of several parts of the spacecraft’s, starting from optical tests on the mirrors or on the telescopes, going on with cryogenic vibration testing of scientific focal plane instruments, ending with the full Planck spacecraft testing. Each test requires temperature lower than 20 [K], in volumes ranging from 1 [m3] to 60 [m3], cooling down several kilograms to more than one ton, and withstanding heat load up to 150 [W] in stabilization.

The INTELSAT VIII / VIIIA program consists of six communication satellites (of two different designs) being produced by Lockheed Martin Astro Space for the International Telecommunications Satellite Organization (INTELSAT). Two spacecraft level thermal vacuum test facilities were required to test the first four spacecraft due to schedule constraints. ...Cal rods were used to independently control the thermal environments of the six spacecraft faces for this facility. A typical cal rod test approach measures cal rod fluxes via calorimeters at discrete locations and controls the applied fluxes based on a correction from the calorimeter to Optical Solar Reflector (OSR) or blanket thermo-optical properties. ...Three thermal balance cases, simulating equinox beginning of life, winter solstice end of life, and inverted spacecraft winter solstice end of life were common to the 801 and 802 test profiles. A comparison of these three balance cases confirms that the developed cal rod equivalent sink test technique is a good substitute for the hot wall test approach when chamber multiple zone temperature control is unavailable.

In 1998, the first element of the Earth Observing System, the EOS-AM1 spacecraft, will be launched into a sun-synchronous polar orbit. The EOS-AM1 platform will include five instruments that will form the payload used to provide information on global climate change. ...The EOS-AM1 platform will include five instruments that will form the payload used to provide information on global climate change. The spacecraft will also include a dual frequency (Ku- and S-band) High Gain Antenna (HGA) which will serve as the primary system for transmitting the science data and spacecraft telemetry & command data to the ground via the TRDSS (Tracking and Data Relay Satellite System) network. ...The spacecraft will also include a dual frequency (Ku- and S-band) High Gain Antenna (HGA) which will serve as the primary system for transmitting the science data and spacecraft telemetry & command data to the ground via the TRDSS (Tracking and Data Relay Satellite System) network.

Computer analyses of satellite power systems have generally been divided into two categories. The first may be referred to as System Level Studies, which generally develop mathematical relationships for the power system components, and which are used for ‘high level’ examinations such as energy balance analysis and simplified dynamics studies. The second category of analyses is Circuit Level Studies, which develop circuit level models of the power system electronics, and are typically used for studies such as stability analysis, load transient studies and bus impedance characterizations. Unfortunately, the two categories of analyses are generally not integrated. That is, it is not usually possible to begin with a system level model, and develop it into a detailed circuit model for further studies. In the past, software tools that were suitable for system level studies were not convenient or practical for circuit analysis.