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The Marshall Space Flight Center (MSFC) has numerous spacecraft design challenges past, present, and future. Many of these tasks require multidiscipline analyses to develop a complete design.

This paper describes the methods used by NASA for finding the “best” design approach for meeting the objectives of space exploration. Models of the design process and the role that cost analysis plays in the process will be described. The state-of-the-art of cost estimating will be discussed and a cost model designed for the exploration initiative will be presented. The Space Exploration Initiative will be discussed and a cost estimate presented.

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.

The testing division of the European Space research and Technology Center (ESTEC) upgraded its TEMPerature Data Acquisition System (TEMPDAS) of the Large Space Simulator (LSS) by adding a PlaTinum resistor Data Collection Unit (PTDCU). The unit is integrated in the rotating part of the LSS motion simulator. It is therefore operating at extreme temperatures and under vacuum, as it is for flight equipment.

Currently, Space Shuttle flights rely upon stored expendables for the generation of potable water (via fuel cells) and waste fluids such as himidity condensate and urine are stored for return to earth and subsequent disposal. Water is not presently recycled due to the relatively short nature of each mission. On future long duration Space Station flights (i.e., 90-day resupply) most of the water from urine, humidity condensate, hygeine water (shower and hand wash) and ultimately clothes and dishwashers will be recycled to eliminate the launch weight penalties associated with large amounts of water. Consider that each crewperson requires about 17 liters (4.5 gallons) of water daily. On a 90-day mission with a six member crew, a water supply of 9159 kilograms (20,242 pounds) would be required.

Instrumentation, consisting of a Shuttle Particle Sampler (SPS) and a Shuttle Particle Monitor (SPM), has been developed to characterize the airborne particulate matter in the Space Shuttle cabin during orbital flight. The SPS size selectively collects particles in four size fractions (0-2.5, 2.5-10, 10-100, and >100 μm) which are analyzed postflight for mass concentration and size distribution, for elemental composition, and for morphology. The SPM provides a continuous record of particle concentration through photometric light scattering. Measurements were performed onboard Columbia, OV-102, during the flight of STS-32 in January 1990. No significant changes were observed in the particle mass concentration, size distribution or chemical composition in samples collected during flightday 2 and flightday 7. The total mass concentration was 56 μg/m3 with approximately half of the particles larger than 100 μm.

Iodine is a flight-proven disinfectant which because of its unique properties, will probably be used on the Space Station and future manned spaceflight applications. However, present knowledge of and experience with iodination is insufficient to assess crew safety when used in conjunction with reclamation or recycle systems, especially if the reclaimed water is consumed.

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.

A pumped, two-phase heat-transport system is being developed for possible use for temperature control of scientific instruments on future NASA missions. As compared to a single-phase system, this two-phase system can maintain tighter temperature control with less pumping power. A laboratory model of the system has been built and tested. The measured heat transfer coefficients were approximately the same as in heat pipes, 220 Btu/hr-ft2-F, as compared to 25 Btu/hr-ft2-F for single-phase liquid flow. Heat sharing between experiments has been demonstrated wherein vapor generated in the cold plate of an active experiment was condensed in a cold, unhealed experiment. System stability has been observed. However, additional development is needed. The use of non-azeotropic mixtures of coolants appears especially promising as a simple way to determine exit quality and thus control the flow rates to prevent dryout.

Manned activity within a closed environment will generate a variety of wastes, both stable and potentially biodegradable. The wastes can never be totally eliminated: waste management aims to make a change of form which is both advantageous in terms of volume and hazard reduction and which does not compromise crew health and safety. Micro-organisms will be carried on board by the crew and will be present in the wastes. The fundamental philosophy of our waste management concept is to specifically exclude or specifically include this inherent microbial activity. The complete safe stabilization of waste requires its exclusion while the ultimate need of element recycle will rely on microbial conversion processes.

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.

A two-stage steam gasification and reforming process was evaluated for converting wastes generated within enclosed habitable environments into synthesis gas (CO & H2) and other recyclable inorganic species, i.e. water, CO2 and inorganic salts. Waste compounds used in the experimentation included: cellulose; urea; methionine; sucrose; butyric acid; Igepon TC-42 - a particularly (chemically) stable soap selected by NASA for use in space life support systems; wheat straw and a high density polyethylene. The compounds were tested individually and in combination to simulate the wastes anticipated within enclosed habitat environments.

A regulated high voltage solar array/battery system using large area silicon solar cells and a group of Ni-H energy storage cells meets the requirements of a multikilowatt geosynchronous orbit application. The electrical power bus operates at approximately 50 Vdc, minimizing unbalanced magnetic torques and distribution harness weight. The program design goal of 12 years of operation on station, including up to 2 years of orbital storage, represents a significant extension of total mission life.

This paper describes the application of capacitive propellant gaging techniques to the aerospace enivronment. The propellant utilization and gaging system developed for Apollo is presented. In addition, some problems peculiar to aerospace and the solutions of these problems are discussed.

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.

Recent development programmes have demonstrated that considerable improvements in the thermal and mechanical properties of CMX optical solar reflectors (OSRs) can be achieved. Optical coatings have been used to increase infra-red emittance by 4% and to decrease solar absorptance by 50% enabling more efficient thermal control. Another programme aimed at enhancing the mechanical strength of OSRs, has resulted in a chemical process which can increase the glass strength to more than four times its untreated value. This product improvement, in parallel with new automated test equipment for proving the strength of each reflector, should dramatically reduce the numbers damaged during assembly processes and hence provide considerable cost savings.

A high-temperature, low-power electrochemically-driven fluid cooling pump is currently being developed by Lynntech, Inc. With no electric motor and minimal lightweight components, the pump is significantly lighter than conventional rotodynamic and displacement pumps. Reliability and robustness is achieved with the absence of rotating or moving components (apart from the bellows). Lynntech has recently demonstrated the feasibility of long term pump operation at temperatures of up to 100 °C, and extended storage at temperatures as low as -60 °C. Characteristics of the electrochemically-driven pump are described and the benefits of the technology as a replacement for electric motor pumps in mechanically pumped single-phase fluid loops (MPFL), such as that used in the Mars Pathfinder (MPF), is discussed.