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A generalized approach used in the thermal analysis of complex orbiting spacecraft is presented. The approach, consisting of the development of a mathematical model and its refinement, using verification testing, has allowed close predictions of actual spacecraft temperatures during flight. ...The approach, consisting of the development of a mathematical model and its refinement, using verification testing, has allowed close predictions of actual spacecraft temperatures during flight. The application of this approach in the analysis of the Injun V (Explorer 40) spacecraft is presented as an example. ...The application of this approach in the analysis of the Injun V (Explorer 40) spacecraft is presented as an example.

The paper presents feasibility and effectiveness of an innovative algorithm for spacecraft attitude determination, based on the real time fusion of raw data measurements provided by APS cameras, less limited by metrological constraints than traditional cameras used for star detection, and MEMS gyros, characterized by low-mass, low-power and low recurrent costs. ...Indeed, the availability of the gyro measurement data significantly contributes to the robustness of the spacecraft attitude measurement system particularly in “lost in space” and in “occulted camera” conditions. ...The main novelty content and expected advantages with respect to the state-of-art are illustrated in detail, involving the following four main aspects: 1. fusion at the raw data level of all the gyro and camera measurements, what increases the spacecraft attitude measurement robustness and accuracy 2. Camera model self calibration. 3. Camera and gyro on board attitude estimation. 4.

In this paper we report on the development of the air quality monitoring and early detection system for an enclosed environment with specific emphasis on manned spacecraft. The proposed monitoring approach is based on the distributed parameter model of contaminant dispersion and real-time contaminant concentration measurements.

Most interestingly, the relative state errors are significantly less than the individual errors in the two spacecraft absolute states and that the technique is virtually immune to refraction and relativistic effects.

This paper presents a proposal for thermal analysis running cloned models varying the characteristics of the thermal mathematical models. This type of analysis improves the knowledge of the thermal performances of any space segment, anticipating the problems and reducing the critical iterative analysis process. To perform this type of analysis the stochastic theory and the Monte Carlo method are used. This will be applied to the critical periods like worst case determination, sensitivity analysis, design limits or test correlation. This methodology has been applied with very nice results and some of them will be shown.

New thermal control systems like evaporator heat sinks are integrated into the Active Thermal Control System and into the Flight Control System of Space Planes. The development of these new systems is performed through mathematical process analyses and tests. This paper concerns the establishment of a Thermal Mathematical Model (TMM) for the analyses. The design of the HERMES Water Evaporator Assembly (WEA) is presented. The thermodynamics and numerical requirements upon a TMM for heat exchangers are derived and explained in detail. As an example the WEA TMM is depicted and results of transient analyses are discussed.

This paper presents application of multi-objective optimization to the design of spacecraft power subsystem. The selection of optimum design can be achieved by having a comparative trade study among different alternatives available. ...The paper provides a methodology to optimize the SEPS (Spacecraft Electrical Power Subsystem) design process taking into account both the technology trades and initial sizing in a constrained environment. ...Then it presents spacecraft power system sizing, which is derived by the mission requirements and design constraints imposed by technology available.

A passive thermal control system is provided for the temperature control of the panchromatic camera of IRS-1C spacecraft. The camera with a spatial resolution of better than 10m and a revisiting capability requires a stringent thermal control system.

The thermal behaviour of spacecraft especially of manned ones is governed by various thermophysical effects. Heat transfer by radiation, conduction and convection influence the overall behaviour of the spacecraft. ...Heat transfer by radiation, conduction and convection influence the overall behaviour of the spacecraft. Energy production, distribution and consumption have also strong impacts on the temperature field prevailing in the spaceplane. ...Moreover, chemical reactions, metabolic rates of the crew and external heat loads determine the thermal behaviour of the spacecraft. For design and optimisation of the system and its subsystems a mathematical model is required which describes these effects.

For the past three decades spacecraft thermal analysis has been predominantly performed using lumped parameter solvers such as ESATAN and SINDA.

This paper presents the results of the breadboarding study phase of a Fourier transform infrared spectrometer (FTIR) based trace gas monitor for the use on-board a manned spacecraft. The FTIR system configuration includes a multiple-reflection long path gas cell, a half-wavenumber resolution interferometer, and a mercury-cadmium-telluride (MCT) detector. ...The achieved results show high accuracy in detecting trace gases in the range between the (lower) long-term and (higher) short-term Spacecraft Maximum Allowable Concentration (SMAC) limits. The project has demonstrated a good proof-of-concept for the use of an FTIR system in manned space flights.

The system consists of integrated applications to perform: surface and solid modeling, radiation coupling, orbital analysis, characterization of the thermal radiation heating environment for a spacecraft in orbit or on a planet surface, conduction network generation, two-phase flow modeling and analysis, temperature predictions, and general purpose post-processing. ...While TSS is tailored for spacecraft thermal analysis, it may be used for any general purpose thermal analysis as well. The TSS user interface allows simultaneous menu and command line input.

The temperature control and check valve (TCCV) in a condensing heat exchanger (CHX) controls the amount of atmosphere that flows through or around the CHX depending on the amount of cooling required. This paper presents a new control scheme based on a Fuzzy-PI algorithm to control the CHX. It is realized by the application of Fuzzy-PI controller to the TCCV. The algorithm uses instantaneous and longer-term changes in measured temperature to continually adjust the TCCV position and maintain the atmospheric temperature within specified limits. There is a control threshold switching between PI and Fuzzy control. When the absolute error is higher than the threshold fuzzy control is used, otherwise PI control is used. Simulation is conducted, whose results show that the proposed control scheme makes it possible to improve temperature stability and control precision.

In this paper, we report on the development of an intelligent system for air quality monitoring and early detection and diagnosis of air contaminants. Optimal identification of contaminants is based upon the use of an Implicit Kalman Filter that uses both experimental data and a theoretical model to obtain optimal estimates. We have developed a three-dimensional unsteady-state model of contaminant transport, which uses a flow field generated numerically for the cabin using a finite element mesh. The optimal contaminant estimates are used as the basis for the detection of a contamination event. The algorithm is shown to distinguish between sensor faults and process faults.

Increasingly complex missions with reduced budgets has placed a premium on “better, cheaper, faster” system approaches for producing spacecraft. The natural consequence of this pressure to improve quality while reducing process time and expense is that activities once considered essential to design and development are now viewed as luxuries. ...To produce timely inputs during the condensed design phase, the spacecraft subsystem architect must continually improve the efficiency of analysis activities. This type of improvement is particularly necessary in the area of thermal analysis, which is often viewed as a peripheral activity. ...However, through the use of enhanced software analysis tools, the thermal engineer can ensure a comprehensive spacecraft thermal analysis that yields timely system design inputs in a cost-effective manner.

Optimal power generation and storage technology suites must be selected based on the overall spacecraft mission and hardware design to insure a minimum system cost. Several new technologies in solar generation (high efficiency multi-junction GaAs-based cells, concentrator arrays, thin film cells, etc.) offer increased performance and/or reduced system-level cost. ...In addition, battery technologies often impact the spacecraft thermal control system and overall dry mass. This paper discusses the design algorithms implemented and executed at The Aerospace Corporation to determine optimal power subsystem suites as a function of spacecraft design and total system cost. ...This paper discusses the design algorithms implemented and executed at The Aerospace Corporation to determine optimal power subsystem suites as a function of spacecraft design and total system cost. The analysis includes ballistic coefficient, disturbance torque, station keeping, and temperature control requirements and links these parameters to design impacts in the propulsion, attitude determination and control, and thermal subsystems.

The Microcomputer Spacecraft Thermal Analysis Routines (MSTAR) software package is being developed for NASA/Goddard Space Flight Center by Swales and Associates, Inc. ...Thermal analysis of large-scale spacecraft are currently being performed with industry standard programs such as SSPTA1, VIEW2, and TRASYS3.

For the determination of the solar absorptance αs and the thermal emittance ε optical methods are preferred. These optical measuring procedures are relatively exact. They also deliver information about any potential spectral selective behaviour of surfaces. However, special measuring equipment is required. Particularly if space simulation facilities are already available, the method presented in [1] appears as a suitable enrichment of the measurement methods for the determination of the thermooptical properties αs and ε. It is possible with slight technical expense to expand the usage potential of such facilities. For this paper the same test rig as in [1] is used. In a common space simulation chamber (vacuum; cryogenic shroud; solar simulator) a test item (target) is arranged. In different measuring phases the target is heated up by an integrated electrical heater or by solar irradiation. The arrangement (target / shroud) is regarded as a two node model.

The Microcomputer Spacecraft Thermal Analysis Routines (MSTAR) software package is being developed for NASA/Goddard Space Flight Center by Swales and Associates, Inc.

The application of this method allows to set up a diagnostic experiment using spacecraft (SC) on-board systems, to identify radiation parameter values based on indirect information on transient temperature changes of the TCC test specimens, and to perform a long-term prediction of the TCC's integrated absorptance variations.