Space Mission Design Research Articles

Una Revisión de Técnicas de Optimización Heurística para el Diseño de Trayectorias Interplanetarias en Misiones Espaciales

In this paper, heuristic optimization of interplanetary trajectories is presented. These techniques have been applied over the last two decades to the successful design of space missions in order to increase the scientific results. The multi-objective optimization problem has been solved finding a trade-off between minimizing the fuel and maximizing the useful payload of the scientific mission. A review of the literature related to the application of some evolutive strategies such as Genetic Algorithms and Differential Evolution, and Particle Swarm Optimization methods, to aerospace applications is included, in particular for the design of interplanetary exploration missions with gravity assistances. A detailed example is included to show the application of multiobjetive optimization (MOPSO) to determine the interplanetary trajectory from the Earth to the Kuiper Belt with flybys in Mars, Jupiter and Saturn.

Limiting oxygen concentration (LOC) of burning polyethylene insulated wires under external radiation

Electrical cables and harnesses have been identified as a potential source of fire in the spacecraft cabin. Future space missions may require spacecraft cabin environments to have elevated oxygen concentrations and reduced ambient pressures which could change the wire fire behaviors. In this work, a group of experiments is conducted to measure the flammability limit of polyethylene (PE) insulated wires under varying oxygen concentration and external radiation. Wires with different insulation dimensions, core conditions (with and without copper core) and insulations (LDPE, HDPE and black LDPE) are examined. Experiments show that external radiation extends the burning limit of the wire insulation to a lower limiting oxygen concentration (LOC) in a linear manner for all wire configurations. Comparison also reveals that the copper core acts as a heat sink to reduce the wire flammability, similar to its role in the ignition of wire insulation, while different from the heat source found in flame spread over the wire insulation. It is also observed that with the external radiation, LDPE insulated wire become less flammable than HDPE and black LDPE insulated wires, in contrast to the result without external radiation. A simple theoretical analysis shows that (1) the in-depth radiation through the semi-transparent LDPE to the copper core acts as an additional cooling to weaken the external radiative heating, and (2) the easier dripping of molten LDPE reduces its flammability. The results of this work provide valuable information about the fire risk of electrical wires under variable oxygen concentration and external heating from an adjacent fire. Thus, it may be useful toward upgrading the fire safety design and standards of future space missions.

Stereovision-based pose and inertia estimation of unknown and uncooperative space objects

Autonomous close proximity operations are an arduous and attractive problem in space mission design. In particular, the estimation of pose, motion and inertia properties of an uncooperative object is a challenging task because of the lack of available a priori information. This paper develops a novel method to estimate the relative position, velocity, angular velocity, attitude and the ratios of the components of the inertia matrix of an uncooperative space object using only stereo-vision measurements. The classical Extended Kalman Filter (EKF) and an Iterated Extended Kalman Filter (IEKF) are used and compared for the estimation procedure. In addition, in order to compute the inertia properties, the ratios of the inertia components are added to the state and a pseudo-measurement equation is considered in the observation model. The relative simplicity of the proposed algorithm could be suitable for an online implementation for real applications. The developed algorithm is validated by numerical simulations in MATLAB using different initial conditions and uncertainty levels. The goal of the simulations is to verify the accuracy and robustness of the proposed estimation algorithm. The obtained results show satisfactory convergence of estimation errors for all the considered quantities. The obtained results, in several simulations, shows some improvements with respect to similar works, which deal with the same problem, present in literature. In addition, a video processing procedure is presented to reconstruct the geometrical properties of a body using cameras. This inertia reconstruction algorithm has been experimentally validated at the ADAMUS (ADvanced Autonomous MUltiple Spacecraft) Lab at the University of Florida. In the future, this different method could be integrated to the inertia ratios estimator to have a complete tool for mass properties recognition.

Design of a Nanosatellite Ground Monitoring and Control Software - a Case Study

The growing countries that have carried out the development of CubeSat missions for academic purposes do not offer aerospace engineering programs at their universities. This causes difficulties for traditional engineers upon the formal use of different standards and frameworks for aerospace development, such as the European Cooperation for Space Standardization and Space Mission Analysis and Design . One way in which traditional software engineers can easily understand the structure of an aerospace framework, in order to apply it on the development of CubeSat mission software parts, is comparing its most important elements in relation to the elements suggested by a more familiar method. In this paper, we present a hybrid framework between the ECSS-E-ST-40C standard and the Rational Unified Process, which can be used by traditional software engineers as a guide model for the development of software elements in academic nanosatellite missions. The model integrates the processes and documentation suggested by the ECSS-E-ST-40C with the disciplines, workflows and artifacts suggested in Rational Unified Process. This simplifies the structure of ECSS-E-ST-40C and allows traditional software engineers to easily understand its work elements. The paper describes as study case the implementation of the hybrid model in the analysis and design of ground monitoring and control software for the Libertad-2 satellite mission, which is currently being developed by the Universidad Sergio Arboleda in Colombia.

Numerical investigation of transport mechanism in four-body problem using Lagrangian coherent structure

Transport mechanism is critical for understanding natural phenomena in the solar system and is beneficial to space mission design. In this study, transport mechanism in the bicircular four-body problem is numerically explored by using Lagrangian coherent structure (LCS), a tool widely used for identifying transport barriers in fluid flow. First, equations of motion of the bicircular problem are derived and five topology configurations of forbidden region are presented. Then, definition and computational method of LCS are introduced. Finally, properties of LCS which are useful for revealing transport mechanism in the four-body problem are numerically investigated.

Automated stable region generation, detection, and representation for applications to mission design

This paper presents an automated algorithm to extract dynamical features, such as stability constraints, from phase space maps. The functional representation of these constraints allows their inclusion in optimization problems and thus expands the use of dynamical tools in space mission design. The challenge to autonomously detect the regions of interest in stability maps is discussed through utilizing image processing algorithms to cluster map data. Additionally, to use the detected regions, both discrete and smooth functional representations are studied. Based on similar clustering techniques that have been considered in extracting and representing features of phase space maps, we proposed an adaptively map generation algorithm. It creates a nonuniform grid of points on a map which is denser near the boundaries of the regions of interest. Both representation and map generation algorithms provide significant performance enhancements in phase space analysis. All these techniques are illustrated on examples of stability maps in small body dynamics.

Orbital dynamics in the planar Saturn-Titan system

We use the planar circular restricted three-body problem in order to numerically investigate the orbital dynamics of orbits of a spacecraft, or a comet, or an asteroid in the Saturn-Titan system in a scattering region around the Titan. The orbits can escape through the necks around the Lagrangian points $L_1$ and $L_2$ or collide with the surface of the Titan. We explore all the four possible Hill's regions depending on the value of the Jacobi constant. We conduct a thorough numerical analysis on the phase space mixing by classifying initial conditions of orbits and distinguishing between three types of motion: (i) bounded, (ii) escaping and (iii) collisional. In particular, we locate the different basins and we relate them with the corresponding spatial distributions of the escape and crash times. Our results reveal the high complexity of this planetary system. Furthermore, the numerical analysis shows a strong dependence of the properties of the considered basins with the total orbital energy, with a remarkable presence of fractal basin boundaries along all the regimes. We hope our contribution to be useful in both space mission design and study of planetary systems.

Methodology for requirements definition of complex space missions and systems

The paper deals with the description of a methodology to properly perform space mission design, with particular attention to derivation of requirements.Several tools are usually adopted to support the design of complex missions and systems, but no very rigorous processes are available for the derivation of requirements. The methodology proposed in this paper aims at providing a general approach to exploit the main system engineering analyses and tools for a thorough assessment of the requirements. Specifically, it addresses how each category of requirements can be derived by appropriate analyses and what is generally the sequence of derived requirements categories.The very first design step is mission statement and objectives definition. A parallel activity is the stakeholders׳ needs׳ analysis, mainly based on identifying all mission׳s actors and their expectations, thus deriving additional objectives. Once the broad objectives of the missions have been established, the following step of the design methodology is the Functional Analysis, which allows identifying the major functions to be performed for the mission׳s accomplishment, as well as the needed physical components. Another important analysis is related to the Concept of Operations, which has the scope of describing how the system is operated during its life-cycle phases to meet stakeholders׳ expectations. The overall process relies on the use of specific software tools, which provide useful means for the analyses integration giving also the chance to easily track and verify the results.The paper reports a detailed description of the methodology, as well as an example case study in order to provide a clearer understanding of the entire process. The analyzed case refers to in-orbit validation of inflatable technology, which is one of the most significant technologies to be developed for future human space missions to deep space targets. Future human exploration programs point towards new and more challenging objectives, which require the development of new advanced systems and technologies, and their demonstration in space environment. Indeed a system is considered flight-qualified, once it has completed a demonstration mission in space environment. Accordingly, there is a great interest in the definition and analysis of dedicated missions for the in-orbit demonstration of advanced technologies.The developed design methodology and the results obtained by applying the methodology have been obtained in the framework of STEPS-2 (Sistemi e Tecnologie per l’EsPlorazione Spaziale-Phase 2). STEPS-2 is a research project co-founded by EU on the “Misura Piattaforme Innovative”-Phase 2 of POR FESR 2007/2013.

The International Safety Framework for nuclear power source applications in outer space—Useful and substantial guidance

In 2009, the International Safety Framework for Nuclear Power Source Applications in Outer Space was adopted, following a multi-year process that involved all major space faring nations under the auspices of a partnership between the UN Committee on the Peaceful Uses of Outer Space and the International Atomic Energy Agency. The Safety Framework reflects an international consensus on best practices to achieve safety. Following the 1992 UN Principles Relevant to the Use of Nuclear Power Sources in Outer Space, it is the second attempt by the international community to draft guidance promoting the safety of applications of nuclear power sources in space missions.NPS applications in space have unique safety considerations compared with terrestrial applications. Mission launch and outer space operational requirements impose size, mass and other space environment limitations not present for many terrestrial nuclear facilities. Potential accident conditions could expose nuclear power sources to extreme physical conditions.The Safety Framework is structured to provide guidance for both the programmatic and technical aspects of safety. In addition to sections containing specific guidance for governments and for management, it contains technical guidance pertinent to the design, development and all mission phases of space NPS applications.All sections of the Safety Framework contain elements directly relevant to engineers and space mission designers for missions involving space nuclear power sources. The challenge for organisations and engineers involved in the design and development processes of space nuclear power sources and applications is to implement the guidance provided in the Safety Framework by integrating it into the existing standard space mission infrastructure of design, development and operational requirements, practices and processes. This adds complexity to the standard space mission and launch approval processes.The Safety Framework is deliberately generic to remain relevantly independent of technological progress, of national organisational setups and of space mission types. Implementing its guidance therefore leaves room for interpretation and adaptation. Relying on reported practices, we analyse the guidance particularly relevant to engineers and space mission designers.

Spacecraft for Hypervelocity Impact Research – An Overview of Capabilities, Constraints and the Challenges of Getting There

We present an introductory overview of the capabilities, constraints and challenges to be taken into account in the design of space missions for HVI research and application, focusing on related planetary defence applications, small spacecraft approaches, using our activities and projects as examples. Large lightweight deployable structure applications are discussed, for large-scale photovoltaic arrays in advanced solar-electric propulsion missions, and for solar sailing as a non-fuel-constrained method of achieving high-energy or retrograde orbit and multiple target missions. Small asteroid landers are discussed as vehicles for precursor exploration of impact target asteroids, precision target orbit determination, and for impact process monitoring that also can be deployed from sail-based missions.

Transfer to a Multi-revolution Elliptic Halo orbit in Earth–Moon Elliptic Restricted Three-Body Problem using stable manifold

The Multi-revolution Elliptic Halo (ME-Halo) orbit is a special kind of symmetric periodic orbits generated in the Elliptic Restricted Three-Body Problem (ERTBP). Its special properties, including a long period and a redundant stable direction, make it a promising nominal orbit in space mission design. In this paper, direct transfer to an ME-Halo orbit using its three-dimensional stable manifold is investigated in the Earth–Moon system. At first, perigee transfers along the main stable manifold are constructed, and different orbit injection points are surveyed. Then the manifold injection point is optimized locally. The impact of the redundant stable direction of the ME-Halo orbit is analyzed through a survey of apogee transfers using both of its two stable directions. This paper presents a first exploration of transferring to ME-Halo orbits, which is directly performed in the ERTBP. Results in this paper will enrich the preliminary space mission design by providing feasible strategies to reach ME-Halo orbits.

Synergistic effect of high charge and energy particle radiation and chronological age on biomarkers of oxidative stress and tissue degeneration: a ground-based study using the vertebrate laboratory model organism Oryzias latipes.

High charge and energy (HZE) particles are a main hazard of the space radiation environment. Uncertainty regarding their health effects is a limiting factor in the design of human exploration-class space missions, that is, missions beyond low earth orbit. Previous work has shown that HZE exposure increases cancer risk and elicits other aging-like phenomena in animal models. Here, we investigate how a single exposure to HZE particle radiation, early in life, influences the subsequent age-dependent evolution of oxidative stress and appearance of degenerative tissue changes. Embryos of the laboratory model organism, Oryzias latipes (Japanese medaka fish), were exposed to HZE particle radiation at doses overlapping the range of anticipated human exposure. A separate cohort was exposed to reference γ-radiation. Survival was monitored for 750 days, well beyond the median lifespan. The population was also sampled at intervals and liver tissue was subjected to histological and molecular analysis. HZE particle radiation dose and aging contributed synergistically to accumulation of lipid peroxidation products, which are a marker of chronic oxidative stress. This was mirrored by a decline in PPARGC1A mRNA, which encodes a transcriptional co-activator required for expression of oxidative stress defense genes and for mitochondrial maintenance. Consistent with chronic oxidative stress, mitochondria had an elongated and enlarged ultrastructure. Livers also had distinctive, cystic lesions. Depending on the endpoint, effects of γ-rays in the same dose range were either lesser or not detected. Results provide a quantitative and qualitative framework for understanding relative contributions of HZE particle radiation exposure and aging to chronic oxidative stress and tissue degeneration.

Escape dynamics and fractal basin boundaries in the planar Earth–Moon system

The escape of trajectories of a spacecraft, or comet or asteroid in the presence of the Earth–Moon system is investigated in detail in the context of the planar circular restricted three-body problem, in a scattering region around the Moon. The escape through the necks around the collinear points $$L_1$$ and $$L_2$$ as well as the leaking produced by considering collisions with the Moon surface, taking the lunar mean radius into account, were considered. Given that different transport channels are available as a function of the Jacobi constant, four distinct escape regimes are analyzed. Besides the calculation of exit basins and of the spatial distribution of escape time, the qualitative dynamical investigation through Poincare sections is performed in order to elucidate the escape process. Our analyses reveal the dependence of the properties of the considered escape basins with the energy, with a remarkable presence of fractal basin boundaries along all the escape regimes. Finally, we observe the plentiful presence of stickiness motion near stability islands which plays a remarkable role in the longest escape time behavior. The application of this analysis is important both in space mission design and study of natural systems, given that fractal boundaries are related with high sensitivity to initial conditions, implying in uncertainty between safe and unsafe solutions, as well as between escaping solutions that evolve to different phase space regions.

Estimación de la cantidad de potencia suministrada por las celdas fotovoltaicas de un cubesat

Los CubeSat son pequeños satélites que, debido a las restricciones propias de sus dimensiones, tienen como única fuente de energía celdas foto-voltaicas sobre su superficie. El propósito de este artículo es estimar la cantidad máxima de poten­cia que puede obtenerse de estas celdas solares, de manera que sea posible realizar un balance de energía cuando se diseñan misiones espaciales con este tipo de satélites. En el escenario anali­zado, un CubeSat de 10cm x 10cm x 10cm (1U) tiene una cara siempre orientada hacia la Tierra. Se consideran las pérdidas por el coseno del ángulo y la variación de la temperatura debido a la órbita del satélite. Para la estimación se usa un modelo matemático de las celdas solares, con el cual se calcula el punto de máxima potencia se­gún el ángulo de incidencia de la radiación solar y la temperatura sobre una órbita baja alrededor de la Tierra. Los resultados muestran la variación de la potencia eléctrica máxima suministrada por los paneles sobre la porción iluminada de la órbi­ta, sin considerar el albedo de la Tierra. Además de la potencia, se estiman las curvas corriente-voltaje para diferentes ubicaciones sobre la órbi­ta del CubeSat.

Comparing and analyzing min-time and min-effort criteria for free true anomaly of low-thrust orbital maneuvers with new optimal control algorithm

This research presents a new algorithm for solving optimal control problems with regard to path planning with a free initial condition. To conduct research in this subject, issues such as optimal control theory, orthogonal functions in the Hilbert space, and the evolutionary optimizations such as Genetic algorithm (GA), Particle swarm optimization (PSO), Genetic algorithm-Particle swarm optimization (GA-PSO) and Imperial competition algorithm (ICA) are utilized. The algorithm is proposed for low-thrust orbital transfer problems, which include nonlinear dynamic equations. To validate the algorithm, Edelbaum low-thrust equations are compared with proposed analytical solutions. Afterwards, the algorithm is investigated for low-thrust orbital transfers concerning equinoctial equations of the min-time and min-effort problems and compared with pseudo-spectral method. Also two performance indices are compared from the viewpoint of space mission analysis and design. In addition, to obtain the best point for starting maneuvers, initial condition of true anomaly is considered to be free. Once the orbital transfer problem is solved, the fuzzy decision maker has to choose the best configuration among the free true anomaly solutions and performance indices to upgrade the proposed algorithm. This configuration balanced two performance indices by considering free true anomaly. As a result, this novel algorithm is able to overcome difficulties of optimal control problems using the global optimization and multi combination performance indices. Another innovation of this new method in the field of optimal control theory is to set initial conditions with more than one performance criterion free.

Spacecraft Engineering: Enhancing Student Engagement by Connecting with the Real World

Abstract A new course in spacecraft engineering for final-year studies was piloted in 2012 at the University of New South Wales' School of Mechanical and Manufacturing Engineering. The course was designed to promote student engagement with the subject by relying heavily on real-world applications of the topics covered. Exam problems were based on actual space missions launched the same week; tutorials included the use of industry-standard software to complement lectures; group assignments covered missions of historical significance; a guest lecture by an industry professional allowed the students to understand the complexities inherent in space mission design; and a field trip to two working space facilities provided an opportunity for students to learn about local involvement in the space industry. The goal was to take a potentially esoteric subject that could easily be taught in an entirely theoretical manner, detached from any meaning to the students, and teach it in a way that demonstrates the direct ...

A greedy global search algorithm for connecting unstable periodic orbits with low energy cost.

A method for space mission trajectory design is presented in the form of a greedy global search algorithm. It uses invariant manifolds of unstable periodic orbits and its main advantage is that it performs a global search for the suitable legs of the invariant manifolds to be connected for a preliminary transfer design, as well as the appropriate points of the legs for maneuver application. The designed indirect algorithm bases the greedy choice on the optimality conditions that are assumed for the theoretical minimum transfer cost of a spacecraft when using invariant manifolds. The method is applied to a test case space mission design project in the Earth–Moon system and is found to compare favorably with previous techniques applied to the same project.

Automated Design of Multiphase Space Missions Using Hybrid Optimal Control

A modern space mission is assembled from multiple phases or events such as impulsive maneuvers, coast arcs, thrust arcs, and planetary flybys. Traditionally, a mission planner would resort to intuition and experience to develop a sequence of events for the multiphase mission and to find the space trajectory that minimizes propellant use by solving the associated continuous optimal control problem. This strategy, however, will most likely yield a suboptimal solution, as the problem is sophisticated for several reasons. For example, the number of events in the optimal mission structure is not known a priori, and the system equations of motion change depending on what event is current. In this work a framework for the automated design of multiphase space missions is presented using hybrid optimal control. The method developed uses two nested loops: an outer-loop that handles the discrete dynamics and finds the optimal mission structure in terms of the categorical variables, and an inner-loop that performs the optimization of the corresponding continuous-time dynamical system and obtains the required control history. Genetic algorithms and direct transcription with nonlinear programming are introduced as methods of solution for the outer-loop and inner-loop problems, respectively. Automation of the inner-loop, continuous optimal control problem solver required two new technologies. The first is a method for the automated construction of the nonlinear programming problems resulting from the use of a transcription method for systems with different structures, including different numbers of categorical events. The method assembles modules, consisting of parameters and constraints appropriate to each event, sequentially according to the given mission structure. The other new technology is for a robust initial guess generator required by the inner-loop nonlinear programming problem solver. The method, based on a real genetic algorithm, approximates optimal control histories by incorporating boundary conditions explicitly using a conditional penalty function. The solution of representative multiphase mission design problems shows the effectiveness of the methods developed.

Biomimetics on seed dispersal: survey and insights for space exploration

Seeds provide the vital genetic link and dispersal agent between successive generations of plants. Without seed dispersal as a means of reproduction, many plants would quickly die out. Because plants lack any sort of mobility and remain in the same spot for their entire lives, they rely on seed dispersal to transport their offspring throughout the environment. This can be accomplished either collectively or individually; in any case as seeds ultimately abdicate their movement, they are at the mercy of environmental factors. Thus, seed dispersal strategies are characterized by robustness, adaptability, intelligence (both behavioral and morphological), and mass and energy efficiency (including the ability to utilize environmental sources of energy available): all qualities that advanced engineering systems aim at in general, and in particular those that need to enable complex endeavors such as space exploration. Plants evolved and adapted their strategy according to their environment, and taken together, they enclose many desirable characteristics that a space mission needs to have. Understanding in detail how plants control the development of seeds, fabricate structural components for their dispersal, build molecular machineries to keep seeds dormant up to the right moment and monitor the environment to release them at the right time could provide several solutions impacting current space mission design practices. It can lead to miniaturization, higher integration and packing efficiency, energy efficiency and higher autonomy and robustness. Consequently, there would appear to be good reasons for considering biomimetic solutions from plant kingdom when designing space missions, especially to other celestial bodies, where solid and liquid surfaces, atmosphere, etc constitute and are obviously parallel with the terrestrial environment where plants evolved. In this paper, we review the current state of biomimetics on seed dispersal to improve space mission design.

Risk attitudes in risk-based design: Considering risk attitude using utility theory in risk-based design

AbstractEngineering risk methods and tools account for and make decisions about risk using an expected-value approach. Psychological research has shown that stakeholders and decision makers hold domain-specific risk attitudes that often vary between individuals and between enterprises. Moreover, certain companies and industries (e.g., the nuclear power industry and aerospace corporations) are very risk-averse whereas other organizations and industrial sectors (e.g., IDEO, located in the innovation and design sector) are risk tolerant and actually thrive by making risky decisions. Engineering risk methods such as failure modes and effects analysis, fault tree analysis, and others are not equipped to help stakeholders make decisions under risk-tolerant or risk-averse decision-making conditions. This article presents a novel method for translating engineering risk data from the expected-value domain into a risk appetite corrected domain using utility functions derived from the psychometric Engineering Domain-Specific Risk-Taking test results under a single-criterion decision-based design approach. The method is aspirational rather than predictive in nature through the use of a psychometric test rather than lottery methods to generate utility functions. Using this method, decisions can be made based upon risk appetite corrected risk data. We discuss development and application of the method based upon a simplified space mission design in a collaborative design-center environment. The method is shown to change risk-based decisions in certain situations where a risk-averse or risk-tolerant decision maker would likely choose differently than the expected-value approach dictates.