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Modern technologies make it possible to fulfill many projects in the field of space exploration. One such project is the colonization of Mars and providing favorable conditions for living on it. Authors propose principles of functioning of the spacecraft with a solar sail, intended to create a thermal and light spot in a predetermined area of the Martian surface. This additional illumination can maintain and support certain climatic conditions on a small area where a Mars base could be located. This paper investigate the possibility of the spacecraft continuously reflect the sunlight off the solar sail on the small area of the Mars surface. The mathematical motion model in such condition of the solar sail’s orientation is considered and used for motion simulation session. Moreover, the analysis of this motion is performed. Thus, were obtained parameters of the synchronic non-Keplerian orbit and spacecraft construction. In addition, were given recommendations for further applying satellites to reflect the sunlight on a planet’s surface. [ABSTRACT FROM AUTHOR]

Nowadays, the leading place in space industry production materials belongs to reinforced polymers. One of the most popular reinforced polymer in this sector is produced from aramid fibers and epoxy resin as matrix with hot solidification at temperature 160 - 170 grad. Celsius. Despite the automated winding technology on modern machinery, there is an accumulation of epoxy resin as a waste happens. This paper is devoted to the processes of curing low-viscosity epoxy resin waste under the influence of orthophosphoric acid (70-75% concentration) and phenol-formaldehyde resin with the addition of biodegradation initiators. For the initiation of biodegradation of xenobiotics, the most affordable, cheap and simple additives were chosen: starch (corn or potato), yeast (simple unicellular microorganisms in nanoscale state), and casein glue of animal origin. Incubation of samples of epoxy resins with the addition of biodegradation initiators in soil medium for 6 months made it possible to detect a significant loss of mass (up to 60%), changes in the material surface and its physicomechanical properties. Microscopic studies have shown the presence of significant growth of microfungi. [ABSTRACT FROM AUTHOR]

The subject matter and many concepts in astronomy are abstract and underlie itsmathematical complexity. The apparent motion of the stars and planets in our sky is difficult to comprehend. Acelestial sphere is commonly used to describe the motions of the stars and planets in the sky. Having students construct a physical model of acelestial sphere rather than exploring a given model is useful to help them understand the motions in the sky. This article describes the process of building asimple celestial sphere to help students understand the motions of the stars in the sky. All of the materials used are inexpensive and readily available. [ABSTRACT FROM AUTHOR]

This paper considers lower limits of length scale in spacecraft: interstellar vehicles consisting of little more material than found in a typical integrated-circuit chip. Some fundamental scaling principles are introduced to show how the dynamics of the very small can be used to realize interstellar travel with minimal advancements in technology. Our recent study for the NASA Institute for Advanced Concepts provides an example: the use of the Lorentz force that acts on electrically charged spacecraft traveling through planetary and stellar magnetospheres. Schaffer and Burns, among others, have used Cassini and Voyager imagery to show that this interaction is responsible for some of the resonances in the orbital dynamics of dust in Jupiter’s and Saturn’s rings. The Lorentz force turns out to vary in inverse proportion to the square of this characteristic length scale, making it a more effective means of propelling tiny spacecraft than solar sailing. Performance estimates, some insight into plasma interactions, and some hardware concepts are offered. The mission architectures considered here involve the use of these propellantless propulsion techniques for acceleration within our solar system and deceleration near the destination. Performance estimates, some insight into plasma interactions, and some hardware concepts are offered. The mission architectures considered here involve the use of these propellantless propulsion techniques for acceleration within our solar system and deceleration near the destination. We might envision a large number of such satellites with intermittent, bursty communications set up as a one-dimensional network to relay signals across great distances using only the power likely from such small spacecraft. Conveying imagery in this fashion may require a long time because of limited power, but the prospect of imaging another star system close-up ought to be worth the wait. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper presents the development of a lightweight 100W-class re-deployable radiator with environment-adaptive functions. This radiator, reversible thermal panel (RTP), which consists of flexible high thermal conductive graphite sheets and a single crystal shape memory alloy as a passive reversible actuator, changes its function from a radiator to a solar absorber by deploying/stowing the reversible fin upon changes in the heat dissipation and thermal environment. A deployment/stowing test in atmospheric condition and a thermal vacuum test were conducted. The fin deployment angle could be changed from 0 deg to 140 deg with the change of the RTP temperature from -40 C to +40 C in the deployment/stowing test using a constant temperature chamber. Autonomous thermal control function was demonstrated in the thermal vacuum test although the fin could not be entirely stowed under cold condition. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Heat rejection from power systems will be necessary for human and robotic activity on the lunar surface. Functional operation of such heat rejection systems is at risk of degradation as a consequence of dust accumulation. The Apollo astronauts encountered marked degradation of performance in heat rejection systems for the lunar roving vehicle, science packages, and other components. Although ground testing of dust mitigation concepts in support of the Apollo mission identified candidate mitigation tools, the brush concept adopted by the Apollo astronauts proved essentially ineffective. A better understanding of the issues associated with the impact of lunar dust on the functional performance of heat rejection systems and its removal is needed as planning gets underway for human and robotic missions to the Moon. Renewed emphasis must also be placed on ground testing of pristine and dust-covered heat rejection system surfaces to quantify degradation and address mitigation concepts. This paper presents a review of the degradation of heat rejection systems encountered on the lunar surface to-date, and discusses current activities underway to evaluate the durability of candidate heat rejection system surfaces and current dust mitigation concepts. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The 2004 NASA Vision for Space Exploration calls for the return of mankind to the moon by no later than 2020, in preparation for an adventure to Mars and beyond. An envisioned lunar outpost will provide living quarters for initially 5– 10 astronauts for up to 2 weeks, and latter for science experiments, and recovery of mineral and indigenous resources for the day-to-day operation and production of propellant. These activities would require electrical and thermal powers in the order of 10’s – 100’s of kilowatts 24/7. Potential power options include photovoltaic, requiring massive batteries or fuel cells for energy storage during the long nights on the moon, and nuclear reactor power systems, which are much more compact and operate independent of the sun. This paper examines the benefit of using the lunar regolith as a supplemental neutron reflector on decreasing the launch mass of the Sectored Compact Reactor (SCoRe-S), developed at the Institute for Space and Nuclear Power Studies. In addition to providing at least $2.00 of hot-clean excess reactivity at the beginning of life, various SCoRe-S concepts investigated in this paper are at least $1.00 sub-critical when shutdown, and when the bare reactor cores are submerged in wet sand and flooded with seawater, following a launch abort accident. Design calculations performed using MCNP5 confirmed that using lunar regolith as supplementary reflector reduces the launch mass of the SCoRe-S cores by ∼ 34% – 35%, or 150 – 200 kg, while satisfying the above reactivity requirements. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Infinia is developing the next generation of space-ready Stirling Convertor Assemblies. Infinia has previously proposed a Low-Mass Stirling Convertor Assembly (SCA) design employing a flux-concentrating, moving-iron linear alternator. This paper describes further development of that proposed machine, including additional improvements and advancements. One significant change is a new, lighter-weight moving-magnet alternator design. Infinia has shown progress in the low mass design’s development and testing: namely in the area of flexure spring rates, welding techniques on the flange, and a change to the alternator configuration. Progress has been made with the flat-top heater head design and its capabilities, as well. The changes described in this paper will significantly reduce the mass and increase the power density of the low-mass design. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The interplanetary space environment is composed mostly of low energy (E < 100 keV) plasma from the solar wind and high energy (E > 1 MeV) protons from solar energetic particle events. Satellites orbiting Earth are shielded to some degree from these events by the Earth’s magnetic field but spacecraft traveling between planets and space nuclear systems on the lunar or Martian surface are exposed to these solar protons directly. A major concern for spacecraft is bulk dielectric charging, a form of spacecraft charging that can lead to dielectric discharges, a form of internal electrostatic discharge (IESD) that can damage sensitive electronics. The majority of research regarding IESD has been concerned with the electrons in the space environment around the Earth and at Jupiter; little research has been done on the charging of spacecraft in interplanetary space due to solar event protons. This paper provides a review of the literature regarding IESD due to protons and presents the results of recent laboratory experiments. Topics for further research are also suggested. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper presents a methodology for analytically comparing approaches to modular assembly of large space platforms. The methodology combines a physical model of the modules, a life-cycle cost model, and a risk model to capture influential trade-offs. The physical model includes alternative module design characteristics, assembly time scenarios, alternative work systems (human, robotic), and infrastructures. A life-cycle cost framework is defined to capture the benefits and costs of modular alternatives for single or multi-mission (programmatic) applications. A probabilistic risk model to address launch and assembly risks is employed to capture uncertainties in launch, as well as in the assembly approaches and their complexity (number of assembly steps, module connections). An illustration of the tradeoffs between these models for a single mission is described using a 448kW Solar Electric Transport Vehicle (SETV) supporting a human lunar mission. The illustration was limited to the launch and assembly phase from beginning of first element launch to completion of assembly. Results and observations are presented and discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Space colonization is not part of NASA’s mission planning. NASA’s exploration vision, mission goals and program implementations, however, can have an important affect on private lunar programs leading towards colonization. NASA’s exploration program has been described as a journey not a race. It is not like the Apollo mission having tight schedules and relatively unchanging direction. NASA of this era has competing demands from the areas of aeronautics, space science, earth science, space operations and, there are competing demands within the exploration program itself. Under the journey not a race conditions, an entrepreneur thinking about building a hotel on the Moon, with a road to an exploration site, might have difficulty determining where and when NASA might be at a particular place on the Moon. Lunar colonization advocates cannot depend on NASA or other nations with space programs to lead the way to colonization. They must set their own visions, mission goals and schedules. In implementing their colonization programs they will be resource limited. They would be like “hitchhikers” following the programs of spacefaring nations identifying programs that might have a fit with their vision and be ready to switch to other programs that may take them in the colonization direction. At times they will have to muster their own limited resources and do things themselves where necessary. The purpose of this paper is to examine current changes within NASA, as a lunar colonization advocate might do, in order to see where there might be areas for fitting into a lunar colonization strategy. The approach will help understand how the “hitchhiking” technique might be better utilized. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

During the summers of 2004, and 2005, several studies were conducted in the Future Concepts Office at the NASA Marshall Space Flight Center (MSFC) with assistance from summer faculty and student program participants to develop concepts and architectures for mobile lunar habitats. This work included conceptual designs for a launch architecture derived from existing expendable launch systems; a lunar walker based on existing technology for the robotics; compatible hardware from the International Space Station (ISS) program for pressurized modules; and lunar resources utilization for environmental shielding. This paper provides a brief summary of some of the key findings from these studies, and identifies areas for future work that could lead to more robust lunar exploration architectures in the future. In conclusion, it is recommended that future exploration missions consider reusable depot / transfer vehicles, robotic walking technology for lunar exploration, and lunar resources utilization for environmental shielding of surface habitats. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The planning and scheduling of human space activities is an expensive and time-consuming task that seldom provides the crew with the control, flexibility, or insight that they need. During the past thirty years, scheduling software has seen only incremental improvements; however, software limitations continue to prevent even evolutionary improvements in the “operations concept” that is used for human space missions. Space missions are planned on the ground long before they are executed in space, and the crew has little input or influence on the schedule. In recent years the crew has been presented with a “job jar” of activities that they can do whenever they have time, but the contents of the jar is limited to tasks that do not use scarce shared resources and do not have external timing constraints. Consequently, the crew has no control over the schedule of the majority of their own tasks. As humans venture farther from earth for longer durations, it will become imperative that they have the ability to plan and schedule not only their own activities, but also the unattended activities of the systems, equipment, and robots on the journey with them. Significant software breakthroughs are required to enable the change in the operations concept. The crew does not have the time to build or modify the schedule by hand. They only need to issue a request to schedule a task and the system should automatically do the rest. Of course, the crew should not be required to build the complete schedule. Controllers on the ground should contribute the models and schedules where they have the better knowledge. The system must allow multiple simultaneous users, some on earth and some in space. The Mission Operations Laboratory at NASA’s Marshall Space Flight Center has been researching and prototyping a modeling schema, scheduling engine, and system architecture that can enable the needed paradigm shift — it can make the crew autonomous. This schema and engine can be the core of a planning and scheduling system that would enable multiple planners, some on the earth and some in space, to build one integrated timeline. Its modeling schema can capture all the task requirements; its scheduling engine can build the schedule automatically; and its architecture can allow those (on earth and in space) with the best knowledge of the tasks to schedule them. This paper describes the enabling technology and proposes an operations concept for astronauts autonomously scheduling their activities and the activities around them. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Space transportation systems require high-performance thermal protection and fluid management techniques for systems ranging from cryogenic fluid management devices to primary structures and propulsion systems exposed to extremely high temperatures, as well as for other space systems such as cooling or environment control for advanced space suits and integrated circuits. Although considerable developmental effort is being expended to bring potentially applicable technologies to a readiness level for practical use, new and innovative methods are still needed. One such method is the concept of Advanced Micro Cooling Modules (AMCMs), which are essentially compact two-phase heat exchangers constructed of microchannels and designed to remove large amounts of heat rapidly from critical systems by incorporating phase transition. The development of AMCMs requires fundamental technological advancement in many areas, including: (1) development of measurement methods/systems for flow-pattern measurement/identification for two-phase mixtures in microchannels; (2) development of a phenomenological model for two-phase flow which includes the quantitative measure of flow patterns; and (3) database development for multiphase heat transfer/fluid dynamics flows in microchannels. This paper focuses on the results of experimental research in the phenomena of two-phase flow in microchannels. The work encompasses both an experimental and an analytical approach to incorporating flow patterns for air-water mixtures flowing in a microchannel, which are necessary tools for the optimal design of AMCMs. Specifically, the following topics are addressed: (1) design and construction of a sensitive test system for two-phase flow in microchannels, one which measures ac and dc components of in-situ physical mixture parameters including spatial concentration using concomitant methods; (2) data acquisition and analysis in the amplitude, time, and frequency domains; and (3) analysis of results including evaluation of data acquisition techniques and their validity for application in flow pattern determination. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper describes development of and test results for an electrostatically switched radiator (ESR). This is a device that can control the radiation emitted from a surface by controlling the position of a thin membrane. The present structure has been fabricated for flight testing on NASA’s ST5 New Millennium program. It consists of 4 separately controlled radiator sections with a total active area of 57.6 cm2. As opposed to the original approach, this structure has the outer membrane at ground potential and is constructed onto a printed circuit board. In this paper we discuss the current state of development of the ESR, including device fabrication and test results. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper a database of sessile drop evaporation on a heated surface under gravity conditions is presented. For this an experimental setup is presented. It includes the part which allows evaporating the drop under controlled conditions and the data acquisition system. The drop is deposited on a heated surface maintained at constant temperature. Two systems were studied: water PTFE (non wetting couple) in which the wetting angle is higher than π/2 and water-aluminum (wetting couple) in which the wetting angle is less than π/2. Two types of measurements are implemented: the first one is an optical method which enables measurements of drop geometrical parameters and consequently the drop evaporation rate. The second one corresponds to a thermal fluxmeter. This later allows the determination of the heat flux and drop temperature. The evaporation rate as well as the geometrical parameters (contact angle, wetting diameter) are determined for several operating conditions: wall temperature and drop size for the two systems considered. For the evaporation rate two different behaviors are found according to drop wetting. The experimental results are discussed and analyzed. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A high-efficiency Stirling Radioisotope Generator (SRG) for use on potential NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company, and NASA Glenn Research Center (GRC). These missions may include providing spacecraft onboard electric power for deep space missions or power for unmanned Mars rovers. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall power system. Performance and mass improvement goals have been established for second- and third-generation Stirling radioisotope power systems. Multiple efforts are underway to achieve these goals, both in-house at GRC and under various grants and contracts. The status and results to date for these efforts will be discussed in this paper. Cleveland State University (CSU) is developing a multi-dimensional Stirling computational fluid dynamics code, capable of modeling complete convertors. A 2-D version of the code is now operational, and validation efforts at both CSU and the University of Minnesota are complementing the code development. A screening of advanced superalloy, refractory metal alloy, and ceramic materials has been completed, and materials have been selected for creep and joining characterization as part of developing a high-temperature heater head. A breadboard characterization is underway for an advanced controller using power electronics for active power factor control with a goal of eliminating the heavy tuning capacitors that are typically needed to achieve near unity power factors. Key Stirling developments just initiated under recent NRA (NASA Research Announcement) awards will also be discussed. These include a lightweight convertor to be developed by Sunpower Inc. and an advanced microfabricated regenerator to be done by CSU. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper reports on the current status of an advanced 35 We free-piston Stirling convertor currently being developed under NASA SBIR Phase II funding. Also described is a further advanced and higher performance ∼80 watt free-piston convertor being developed by Sunpower and Boeing/Rocketdyne for NASA under NRA funding. Exceptional overall convertor (engine plus linear alternator) thermodynamic performance (greater than 50% of Carnot) with specific powers around 100 We /kg appear reasonable at these low power levels. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Previous work has shown that closed-loop Brayton cycle power converters are an extremely attractive option for long-duration (> 10 years) space missions. To date, this technology has been only demonstrated at power levels above 1 kWe. Creare’s progress towards the demonstration of the first-generation, low-power converter for use with radioisotope power sources is the subject of this paper. At the 100 We power level, Brayton systems should attain conversion efficiencies of 20% to 40% depending upon the operating conditions. The converter mass for a flight unit is expected to be about 3 kg. The detailed design, performance predictions, and test plans for the first-generation converter are reviewed in this paper. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]