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A Modeling Framework for Interplanetary Supply Chains
Abstract
As NASA looks ahead to next-generation human space exploration, it is essential to consider the cost of operations and support in order to ensure the development of affordable programs. The life-cycle costs of future exploration ventures can be reduced by focusing on the interplanetary logistics strategy. By leveraging proven supply chain management techniques from the military and commercial sectors and applying them to the unique challenges of human space exploration, space logistics can be streamlined, and mission affordability and robustness can be increased. This paper describes a modeling framework for space logistics which enables description, evaluation, and optimization of various types of logistics strategies. The framework is embodied in SpaceNet, a discrete event simulation and optimization software program.
... First, provisions will be required for crews in the early phases of exploration and for larger assemblages of people as off-Earth human settlements become established. Air, water, food, items for hygiene and personal use, and medicines will all be needed, together with essential tools for daily life and to maintain health and the proper functioning of support items such as clothing and electronic equipment [50,51,52]. Apart from the development of the ISRU, this will require, implementation of agricultural, manufacturing, and air and material recycling techniques that are adapted to vacuum conditions and low gravity [51]. ...
... Likewise, it will be necessary to have transport equipment, propellants and fuels to enable the required rockets and ships to move. This is a vital aspect of space exploration since, unlike the supply chains that we know from Earth, the propellant can represent most of the ship's mass [52]. The use of cislunar space will also require, not only the availability of specific equipment for exploration and scientific research, but also for communications and the stowage and securing of supplies [52]. ...
... This is a vital aspect of space exploration since, unlike the supply chains that we know from Earth, the propellant can represent most of the ship's mass [52]. The use of cislunar space will also require, not only the availability of specific equipment for exploration and scientific research, but also for communications and the stowage and securing of supplies [52]. ...
Humans are exploring outer space with ever-greater scope and are continually pushing the limits of scientific and technological development. Technology readiness has reached a level at which a perspective on commerce and trade in space processing is reasonable. A central element of commerce is the provision of resources to make products and to distribute those to customers, which means the proposition of a supply chain.Supply chains make possible the harmonious flow of both materials and information throughout the various stages necessary for the production of goods and the provision of services. Through properly structured processes and based on the principles of Supply Chain Management (SCM), suppliers, manufacturers, distributors and customers contribute to a reduction of costs and implicitly, improvement of profits in a given supply chain.The environmental conditions in space pose enormous challenges to any production and supply chain, a situation amplified by the logistical obstacles involved in transporting manufactured goods to customers. The long distances involved in space travel demand major technological innovations. The technology leap needed likely requires a partnership between the governmental and private sectors.The Moon, the natural satellite of the Earth, represents the first opportunity for the implementation of economic activities in outer space. Its proximity to Earth, the information that is already available about this celestial body and the ready availability of some of its natural resources puts it in a prime position to structure space supply chains for goods. This may include space between the Moon and Earth, defined as ‘cislunar’ space.A perspective for the structuring of supply chains conceived on the Moon and cislunar space will imply the development of manufacturing capacities for the required space products, as well as the emergence of specialized space suppliers, and space marketers.
... Kallay [5], Gralla et al. [6], Shull et al. [7], Taylor et al. [8], Siddiqi et al. [9], Grogan et al. [10], Ho et al. [11,12], Lin et al. [3], and Zhu et al. [13] studied logistics strategy optimization of space station operations, but in these studies the researchers neglected concentrated explorations on getting the long-term overall distribution scheme of on-orbit activities which is used to guide logistics strategy planning. Bu et al. [4] studied constraint satisfaction and optimization of short-term on-orbit activity scheduling to solve the short-term small-scale activity scheduling problem under complex constraints and Mu et al. [14] studied re-planning strategies for space station short-term on-orbit activities executed in emergencies. ...
... To describe problems more comprehensively, some multi-objective design optimization for spaceflight problems [16,17] and space logistics [3,13] have been proposed in recent years. According to the employment in earlier studies for five activity elements "Priority, Subsystem, Manhours, Power and Communication" in STMP [4,14] and two elements "Mass of Materials and Volume of Materials" in logistics [5][6][7][8][9][10][11][12][13], a many-objective optimization OASSOA model with seven objective functions that reflect the distribution equilibrium of the considered seven on-orbit activity elements in long operation is constructed. Generally, optimization problems that involve simultaneously optimizing many conflicting objectives (four or more than four) are referred to as many-objective optimization problems [18]. ...
... where ID is the unique code number to identify an on-orbit activity; Priority, Subsystem, Manhours, Power and Communication were proposed in the literature regarding to STMP [4,14]; Mass and Volume of required materials are main factors concerned by earlier studies regarding to logistics [5][6][7][8][9][10][11][12][13]: ...
Overall allocation of space station on-orbit activities is the process of allocating a set of on-orbit activities to be executed on the space station in a long-term planning period into several short-term subperiods while balancing logistics demand, resource requirement and the execution priority of on-orbit activities. The basic mathematical model is firstly formulated. Then a heuristic allocation strategy is proposed to reduce optimization difficulty and a hybrid decision-making approach combining physical programming and evolutionary computation is developed to directly search a Pareto-optimal solution, and the performance of these methods in addressing the problem is compared with that of NSGA-III. Three test case with 500, 1000 and 2000 on-orbit activities respectively are simulated to demonstrate the proposed approaches. The results show that the heuristic allocation strategy is effective and performs better than only applying meta-heuristics, and the decision-making approach based on physical programming can efficiently achieve a decision-maker-preferred solution that is converged better than the Pareto frontier obtained by NSGA-III. The obtained allocation scheme satisfies all equilibrium indexes and constraints.
... Kallay [4] first proposed an approach to space-station logistics optimization by selecting and scheduling supply vehicles through the use of dynamic programming techniques. Since its inception in 1998, the ISS has adopted the logistics strategy known as "scheduled resupply", which is based on regular resupply flights determined by the actual demand generated on the space station [5]. Siddiqi et al. [6,7] established a matrix-based modeling approach for analyzing the ISS logistics strategy that constructed a matrix to represent the cargo delivery strategies (prepositioning, carry along, and resupply). ...
... Previous studies on space-station logistics optimization were limited in that the visit times of cargo vehicles were not considered as design variables in the planning model [4][5][6][7][8][9][10][11][12]. In fact, the visit times of different cargo vehicles are coupled with each other because the space-station operational scenario is viewed holistically. ...
... The launch times of the cargo vehicles are required to satisfy the constraints of the launch window, deadline for resupply, and preparation process, i.e., Eqs. (3)(4)(5). Payload manifests of the cargo vehicles are required to satisfy the constraints of the onboard resources' minimum stored quantities, the vehicles' carrying capabilities, and the onboard resources' defined stored quantities at the end of the scenario, i.e., Eqs. (2), (6), and (7). ...
In this study, the optimization of logistics strategies for long-duration space-station operations is investigated; both the visit times and payload manifests of a series of coordinated flights of cargo vehicles are considered at the same time. An optimization model is established that employs both the launch time and manifesting mix of payload classes as design variables and considers the rendezvous launch window, onboard consumption demand, and vehicles' carrying capabilities as constraints. Four metrics are defined to quantify the utilization benefit and operational robustness of a space-station operational scenario. Each metric is used as the optimization objective function, and a genetic algorithm is employed to obtain the optimal solutions. The approach is demonstrated with a notional one-year operational scenario of China's future space station. The results indicate that the visit times of cargo vehicles have a considerable influence on logistics strategies, and each objective function of different metrics yields a different optimal logistics strategy. Copyright © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
... Supply chain management at the interplanetary level will maximize scientific return, minimize transportation costs, and reduce risk through increased system availability and robustness to failures. 1,2 SpaceNet is a model with a graphical user interface (GUI) that allows a user to build, simulate, and evaluate exploration missions from a logistics perspective. 3 The goal of SpaceNet is to provide mission planners, logisticians, and system engineers with a software tool that focuses on what cargo is needed to support future space missions, when it is required, and how propulsive vehicles can be used to deliver that cargo. ...
... Interplanetary supply chains are modeled using a space logistics framework of nodes, arcs, elements, and supplies. 1 These building blocks are integrated via processes and process groups, which describe how elements and supplies move through a time-expanded network of nodes and arcs. The time-expanded network has the ability to capture the time-dependency of interplanetary trajectories, including launch windows and tradeoffs between fuel consumption and time-of-flight 7 . ...
... The five basic process types are wait, transport, transfer, proximity operations, and exploration (surface missions) and are described in previous literature. 1,3 As opposed to previous versions of SpaceNet, elements and processes are now defined in conjunction. The user can select from a collection of elements, such as ISS and Constellation, and upon doing so, will dynamically create instantiations of them. ...
... The focus is on developing the ability to sustain long-term human human presence while reaching deeper into space than ever before. Space logistics, or the movement, storage, and tracking of all crew and equipment necessary to carry out an exploration mission or campaign [2], aims to tackle the challenge of supporting true exploration. It encompasses nearly every aspect of space flight operations with the exception of vehicle and infrastructure design. ...
... They define the how and when in the supply chain. The ISCMLA framework defines five core processes [2]. These are: ...
... An important final step in supply chain design and analysis is the ability to process the simulation output in such a way that architectures can be evaluated and compared [5]. Several metrics (termed measures of effectiveness or MOEs), have been developed hand-in-hand with the simulation and modeling framework to enable the comparative evaluation of logistics architectures [2]. MOEs provide a quantitative way to evaluate specific space exploration scenarios and interplanetary supply chains in general. ...
This thesis covers the development of a framework for the application of revenue management, specifically capacity control, to space logistics for use in the optimization of mission cargo allocations, which in turn affect duration, infrastructure availability, and forward logistics. Two capacity control algorithms were developed; the first is based on partitioning of Monte Carlo samples while the second is based on bid-pricing with high-frequency price adjustments. The algorithms were implemented in Java as a plugin module to SpaceNet 2.0, an existing integrated modeling and simulation tool for space logistics. The module was tested on a lunar exploration concept which emphasizes global exploration of the Moon using mobile infrastructure. Results suggest that revenue management produces better capacity allocations in shorter duration missions, while producing nominal capacity allocations (i.e. those in the deterministic case) in the long run.
... In coordination with NASA"s architectural studies, MIT started the Space Logistics Project to build a research base supporting interplanetary supply chain management and logistical analysis necessary for extended exploration campaigns. The project initially studied several terrestrial analogs to space exploration, including operations in remote terrestrial environments such as the Arctic and Antarctic, commercial supply chains, and military logistics operations, culminating in the development of a space logistics framework [6,7]. ...
... The surface vehicle is reconfigured to an optional transport state before the start of the transport. (6) Alternatively, if there is excess fuel in a particular propulsive vehicle, the remaining delta-v is decreased to zero and Eq. (7) determines the amount of fuel to consume in the burn m burn . ...
... Under baseline crew member demand rates with a crew of six, demands total 8.1 tons during transport to Mars, 20.8 tons during surface operations, and 9.3 tons during return transport.This is, in part, because the baseline demand rates to not take into account closed-loop environmental controls and life support systems (ECLSS) which could significantly reduce the demands for water and waste disposal resources. Assuming a 95% water closure rate and increased usage of reusable hygiene and waste disposal items, crew demand rates are decreased from 7.5 to 3.375 kilograms per person per day while in transit and from6.5 to 2.375 kilograms per person per day while on the surface. 63: Modified Mars exploration crew demands. ...
A space logistics modeling framework to support space exploration to remote environments is the target of research within the MIT Space Logistics Project. This thesis presents a revised and expanded framework providing capabilities to analyze a new set of explorations using a generalized resource flow through a time-expanded network to satisfy exploration demands. The framework is both flexible to model a wide range of destinations using mixed levels of fidelity and modular to enable future expansion through interfaces. The SpaceNet software tool implements the space logistics modeling framework, providing integrated modeling and simulation capabilities for quantitative space exploration campaign analysis. Discrete event simulation identifies logistical infeasibilities and provides quantitative measures of exploration effectiveness to guide trade studies or other campaign analyses. SpaceNet 2.5, a Java executable with an extensive graphical user interface, has been publicly released under an open source license. Four case studies are presented as examples of the modeling framework applied to relevant exploration campaigns. A resupply of the International Space Station from 2010-2015 includes 77 flights of seven different vehicles from six launch sites to investigate the supply capacity under existing resupply strategies. A near-Earth asteroid exploration details a two crew, 14-day tele-operated mission at 1999- AO10 to establish the feasibility requirements of using modified Constellation vehicle architectures. A lunar outpost exploration models the buildup of infrastructure and surface excursions leading to continuous human presence over 21 missions and seven years. Finally, a Mars surface exploration models the ten launches and in-space nuclear thermal rocket propulsion required to send a crew of four to the surface of Mars for a 531-day exploration. Finally, a usability experiment is presented to demonstrate the usability and efficiency of the SpaceNet tool as compared to independent analysis methods. Seven test subjects were tested, five using SpaceNet and two control subjects using spreadsheet-based methods, to analyze and establish the feasibility of a near-Earth object mission. The median SpaceNet subject required 35 minutes to complete the analysis, compared to a median of 113 minutes for the control subjects.
... The International Space Station, for instance, requires regular supply runs from Earth (resupply approach), which is a strategy only viable in near-Earth space [4]. Sustaining a permanent base on another planet, however, poses completely new challenges and thus necessitates a novel space logistics paradigm [4][5][6], which is hereafter referred to as interplanetary supply chain (ISC). ...
... In this context, they emphasize the need for demand-supply modeling approaches that study the impact of uncertainties [7]. Similarly, other researchers highlighted the limitations of current space logistics paradigms and proclaimed the necessity to investigate ISC approaches [4][5][6]. ...
The unique and complex challenges of sustainable interplanetary travel necessitate a novel space logistics paradigm, which is hereafter referred to as the interplanetary supply chain. To lay the groundwork for this anticipated paradigm shift, this work aims to introduce principles and methodologies of supply chain (SC) planning to the field of space logistics. To this end, a stochastic multistage mixed integer linear programming model is proposed that explores the vision of a permanent human presence on Mars from a logistics standpoint. The model optimizes material flows, propellant production, and in-space infrastructure allocations to identify the optimal SC network design. Notably, demand uncertainty at the Mars base is considered, which makes it the first model to investigate the effects of stochasticity in space logistics planning. Several case studies are investigated, which incorporate data on Earth–Mars transfer windows and flight trajectories obtained through the National Aeronautics and Space Administration’s trajectory browser. The results reveal numerous interdependencies and, thus, highlight the need for holistic SC modeling approaches that go beyond the isolated mission planning of the extant literature. For instance, the findings show frequent interactions among spacecraft as they regularly engage in division of labor regarding cargo and propellant transportation. Moreover, complex propellant supply networks that involve strategic in-space infrastructure allocation and propellant production on celestial bodies are established. Overall, the developed model provides valuable insights into the planning of a sustainable interplanetary travel, offers a new SC perspective, and lays the foundation for future research in this area.
... Recognition of these tools helps identify both widely recognised and lesser known risks. Risk assessment tools exist for a number of areas of SCR, including, for example: human-related and cognitive errors (Baysari et al., 2009;Moriyama and Ohtani, 2009), cost risk (GAO, 2015b), governmental acquisition projects (GAO, 2015a), supplier selection decisions (Wu and Olson, 2008), SC quality (Zhang et al., 2011), probabilistic estimating and scheduling tools (Isidore et al., 2001), system probabilistic risk assessment (Modarres, 2006), supplier environmental and density risk (Deane, 2009), quality function deployment and failure modes and effect analysis (Pujawan and Laudine, 2009), and a lifecycle-cost framework for interplanetary SCs (Gralla et al., 2006), among others. ...
... But 'the sky is not the limit' in space logistics, as the hometown motto states for Huntsville, Alabama, home of MSFC. There is also a body of literature on (outer) space logistics (Lin et al., 2014), interplanetary logistics (Gralla et al., 2006), space station logistics (Lin et al., 2014), and lunar logistics (Shull, 2007) (see Figure 5 in Appendix). ...
Over the last two decades, firms, governmental agencies, and non-governmental organisations have sought improved understanding of supply chain management and supply chain risk. Much supply chain risk research has been in large and mature industries such as automotive, aerospace, and energy production. Yet, additional supply chain risk areas are of concern to executives, including emerging industries, emerging supply chains, governmental agencies, quasi-governmental agencies, non-governmental agencies, and large-scale systems engineering projects that cope with complex technical challenges and multi-year development cycles. Through involvement with commercial and governmental research partners, we developed an extended and more generalised framework of supply chain risk that categorises dimensions of SCR and highlights the complexity that must be addressed by organisations. Key findings include that academics must address the complexity that firms face rather than assume simpler risk models, and that firms need additional academic thought leadership for developing improved approaches to manage supply chain risk.
... Recognition of these tools helps identify both widely recognised and lesser known risks. Risk assessment tools exist for a number of areas of SCR, including, for example: human-related and cognitive errors (Baysari et al., 2009;Moriyama and Ohtani, 2009), cost risk (GAO, 2015b), governmental acquisition projects (GAO, 2015a), supplier selection decisions (Wu and Olson, 2008), SC quality (Zhang et al., 2011), probabilistic estimating and scheduling tools (Isidore et al., 2001), system probabilistic risk assessment (Modarres, 2006), supplier environmental and density risk (Deane, 2009), quality function deployment and failure modes and effect analysis (Pujawan and Laudine, 2009), and a lifecycle-cost framework for interplanetary SCs (Gralla et al., 2006), among others. ...
... But 'the sky is not the limit' in space logistics, as the hometown motto states for Huntsville, Alabama, home of MSFC. There is also a body of literature on (outer) space logistics (Lin et al., 2014), interplanetary logistics (Gralla et al., 2006), space station logistics (Lin et al., 2014), and lunar logistics (Shull, 2007) (see Figure 5 in Appendix). ...
Over the last two decades, firms, governmental agencies, and non-governmental organisations have sought improved understanding of supply chain management and supply chain risk. Much supply chain risk research has been in large and mature industries such as automotive, aerospace, and energy production. Yet, additional supply chain risk areas are of concern to executives, including emerging industries, emerging supply chains, governmental agencies, quasi-governmental agencies, non-governmental agencies, and large-scale systems engineering projects that cope with complex technical challenges and multi-year development cycles. Through involvement with commercial and governmental research partners, we developed an extended and more generalised framework of supply chain risk that categorises dimensions of SCR and highlights the complexity that must be addressed by organisations. Key findings include that academics must address the complexity that firms face rather than assume simpler risk models, and that firms need additional academic thought leadership for developing improved approaches to manage supply chain risk.
... Supply chain management at the interplanetary level will maximize scientific return, minimize transportation costs, and reduce risk through increased system availability and robustness to failures. 2,3 SpaceNet is a computational environment that enables users to visually construct exploration missions at both the sortie level and the campaign level. Interplanetary supply chains are modeled using a space logistics framework of nodes, arcs, elements, and supplies. ...
... Interplanetary supply chains are modeled using a space logistics framework of nodes, arcs, elements, and supplies. 2 These building blocks are integrated via processes, which describe how elements and supplies move through a time-expanded network of nodes and arcs. The time-expanded network has the ability to capture the time-dependency of interplanetary trajectories, including launch windows and tradeoffs between fuel consumption and time-of-flight 4 . ...
... Taylor et al [4] developed a MILP-based heuristic commodity flow model for interplanetary transport, in which commodity flow paths are pre-determined and then assigned to logistics vehicles. Later, the SpaceNet space logistics modeling framework utilized time-expanded networks and was used to study ISS, lunar, and interplanetary logistics [5,6]. More recently, multi-commodity flow models have been developed to calculate the optimal flow of spacecraft, payloads, and propellant through space [7,8]. ...
Space exploration plans are becoming increasingly complex as public agencies and private companies target deep-space locations, such as cislunar space and beyond, which require long-duration missions and many supporting systems and payloads. Optimizing multi-mission exploration campaigns is challenging due to the large number of required launches as well as their sequencing and compatibility requirements, making the conventional space logistics formulations not scalable. To tackle this challenge, this paper proposes an alternative approach that leverages a two-level hierarchical optimization algorithm: a genetic algorithm is used to explore the campaign scheduling solution space, and each of the solutions is then evaluated using a time-expanded multi-commodity flow mixed-integer linear program. A number of case studies, focusing on the Artemis lunar exploration program, demonstrate how the method can be used to analyze potential campaign architectures. The method enables a potential mission planner to study the sensitivity of a campaign to program-level parameters such as logistics vehicle availability and performance, payload launch windows, and in-situ resource utilization infrastructure efficiency.
... One of the first projects that leveraged network modeling for space mission design was SpaceNet [103], which is a simulation and visualization software for space logistics operations. This project and its subsequent studies (e.g., Ref. [61,65,[67][68][69][70]72]), primarily focused on supporting human space exploration campaigns with the then-active Constellation Program in mind. Since then, network and graph-theoretic modeling have played a key role in analyzing complex space logistics missions. ...
... Lin et al. [4], [5], [6] used the dynamic programming and two-level optimization approach to study the space station orbital mission planning. Gralla et al. [7] and Siddiqi and de Weck [8], [9] studied multi-node space exploration systems extensively. Lin et al. [10], [11] conducted some research on the logistics strategy optimization of the space station operation. ...
... This formulation was substantially upgraded by Gralla et al. into a more integrated space logistics modeling software that enables simulation of interplanetary logistics as well as its results visualization and evaluation [39,40]. In order to evaluate the results of each scenario, measures of effectiveness (MOEs) were developed as quantitative metrics. ...
This research develops a dynamic logistics network formulation for high-level lifecycle optimization of space mission sequences in order to find an optimal space transportation architecture considering its technology trades over time. The proposed methodology is inspired by terrestrial logistics analysis techniques based on linear programming network optimization. A new model with a generalized multi-commodity network flow formulation and a time-expanded network is developed for dynamic space logistics optimization. The developed methodology is applied to three case studies: 1) human exploration of Mars; 2) human exploration of a near-Earth object (NEO); 3) their combination (related to the concept of the Flexible Path). The results reveal multiple dynamic system-level trades over time and provide recommendations for an optimal strategy for human space exploration architecture. The considered trades include those between in-situ resource utilization (ISRU) and propulsion technologies as well as orbit and depot location selection over time. The numerical results show that using specific combinations of propulsion technologies, ISRU, and other space infrastructure elements effectively, we can reduce the initial mass in low- Earth orbit (IMLEO) by 45-50% compared with the baseline architecture. In addition, the analysis results also show that we can achieve 15-20% IMLEO reduction by designing Mars and NEO missions together as a campaign compared with designing them separately owing to their common space logistics infrastructure pre-deployment. This research serves as a precursor for eventual permanent settlement and colonization of other planets by humans, thus transforming us into a multi-planet species.
... In coordination with NASA's Constellation Program lunar architectural studies in 2004-2005, MIT founded its Space Logistics Project to build a research base supporting interplanetary supply chain management and logistical analysis necessary for extended exploration campaigns. The project initially studied several terrestrial analogs to space exploration, including operations in remote terrestrial environments such as the Arctic and Antarctic, commercial supply chains, and military logistics operations, culminating in the development of a space logistics framework (de Weck and Simchi-Levi 2006, Shull et al. 2006, Taylor et al. 2007). ...
NASA's new direction for human spaceflight reaffirms that Mars is the ultimate goal of human exploration of the inner solar system. Eventually we envision colonies of humans and robots jointly exploring the Red Planet in a collaborative fashion. This paper addresses the challenge of long-term exploration and colonization of Mars from a logistical perspective. Adding to the technical challenges of Martian exploration, Mars transfer trajectories and logistical concerns should be considered in advance. An interplanetary trajectory analysis using a ΔV map and flight opportunity bat chart in addition to a traditional trajectory data table shows Venus flyby flight opportunities can be competitive with direct flights having smaller ΔV (velocity change) and shorter flight times because flyby opportunities open up additional launch windows. Therefore, direct flights should be planned in the early phase of a human Mars exploration campaign and Venus flyby flight opportunities may serve as urgent cargo resupply missions that cannot wait until next direct flight opportunities. Cargo flights for pre-positioning should minimize ΔV while crewed flights should reduce flight time at the cost of higher ΔV to minimize crew exposure to reduced gravity and space radiation during in-space transports. SpaceNet analysis from a logistics perspective reveals that the Mars exploration architecture as described by NASA's Mars DRA 5.0 is propulsively feasible but logistically infeasible without modifications to increase supply capacity during crewed transport and exploration periods. The most constrained transportation legs include the surface habitat (SHAB) and Mars descent/ascent vehicle (MDAV) descents to the Martian surface and the crewed MTV transit to Mars.
Low-energy lunar transfers (LETs) utilize three-body mechanics with fourth-body (solar) perturbations to provide an alternative to direct lunar transfers. The offer of reduced lunar orbit insertion cost in exchange for longer time-of-flight and potentially higher transfer insertion cost presents an interesting trade-off when planning the logistics of multi-mission lunar exploration campaigns. This is particularly true for logistics featuring spacecraft with a variety of launch vehicles and propellant types, as the logistics of each spacecraft are impacted by the costs and benefits of LETs differently. This paper presents a translunar logistics model featuring LETs, discusses the trade-offs versus direct transfers through some case studies, and highlights the scenarios in which LETs prove most useful.
Space station logistics strategy optimisation is a complex engineering problem with multiple objectives. Finding a decision-maker-preferred compromise solution becomes more significant when solving such a problem. However, the designer-preferred solution is not easy to determine using the traditional method. Thus, a hybrid approach that combines the multi-objective evolutionary algorithm, physical programming, and differential evolution (DE) algorithm is proposed to deal with the optimisation and decision-making of space station logistics strategies. A multi-objective evolutionary algorithm is used to acquire a Pareto frontier and help determine the range parameters of the physical programming. Physical programming is employed to convert the four-objective problem into a single-objective problem, and a DE algorithm is applied to solve the resulting physical programming-based optimisation problem. Five kinds of objective preference are simulated and compared. The simulation results indicate that the proposed approach can produce good compromise solutions corresponding to different decision-makers’ preferences.
In transition to a new era of human space exploration, the question is what the next- generation space logistics paradigm should be. The past studies on space logistics have been mainly focused on a "vehicle" perspective such as propulsive feasibility, cargo capacity constraints, and manifesting strategies, with the arbitrarily predetermined logistics network. But how do we select an optimal logistics network? Especially if we can utilize in- situ resources on the Moon and Mars, it will add complexity to network selection problem. The objective of this paper is to develop a comprehensive graph-theoretic modeling framework to quantitatively evaluate and optimize space exploration logistics from a "network" perspective. In an attempt to create such a modeling framework, we develop a novel network flow model referred to as the generalized multi-commodity network flow (GMCNF) model. On top of the classical network flow problems, the GMCNF model proposed in this paper introduces three types of matrix multiplications (requirement, transformation, and concurrency), and also allows loop edges associated with nodes (graph loops) and multiple edges between the same end nodes (multigraph). With this modification, the model can handle multiple commodities that interact with each other in the form of requirement at nodes, transformation on edges, and concurrency within edges. A linear programming (LP) formulation of the GMCNF model is applied to human exploration of Mars. First we solve the baseline problem with a demand that is equivalent to that of the NASA's Mars Design Reference Architecture (DRA) 5.0 scenario. It is found that the solution saves 67.5% from the Mars DRA 5.0 reference scenario in terms of the initial mass in low-Earth orbit (IMLEO) primarily because chemical (LOX/LH2) propulsion is used along with oxygen-rich ISRU. We also present one possible scenario with two "gateway" resource depots at GTO and DTO with orbital transfer vehicles (OTVs) running in the cislunar and Martian systems. Then we solve variant problems that have different settings to see the effect of each factor. Findings include: taking advantage of oxygen-rich ISRU, LOX/LH2 is preferred to nuclear thermal rocket (NTR), the aerobraking option as well as ISRU availability on the Moon make great contributions in reducing the total mass to be launched from Earth, and as the ISRU production rate decreases, ISRU in each location becomes worthless at a certain threshold and the network topology changes toward direct paths using NTR.
As all the world looks ahead to the next generation of human space exploration missions (the USA and Russia even plan to develop new program which will take humans back to the Moon by 2020, to Mars, and beyond), it is quite important to consider the influence of space logistics, which is also a solution to achieve independence and self sufficiency, especially for long-duration complex deep space mission campaigns. In order to ensure that the future missions are feasible, reliable, affordable and sustainable, it is essential to take logistics strategy into account in the early stage of mission designing. This paper first summarizes the concept, technical disciplines, goals and objectives of space logistics, and then briefly introduces the current state of art of space logistics. At the end, the development trend is discussed.
Supply Chain Management (SCM) is a key piece of the framework for America's space technology investment as the Nati onal Aeronautics and Space Administration (NASA), the aerospace industry, and international partners embark on a bold new vision of human and robotic space exploration beyond Low - Earth -Orbit (LEO). This type of investment is driven by the Agency's need fo r cost efficient operational support associated with , processing and operating space vehicles and address many of the biggest operational challenge including extremely tight funding profiles, seamless program -to -program transition activities and the reduct ion of the time gap with human spaceflight capabilities in the post -Shuttle era. An investment of this magnitude is a multiyear task and must include new patterns of thought within the engineering community to respect the importance of SCM and the integrat ion of the material and information flow. Experience within the Department of Defense and commercial sectors which has shown that support cost reductions and or avoidances of upwards to 35% over business as usual are achievable. It is SCM that will ultim ately bring the solar system within the economic sphere of our society. Applying aspects of the high -volume, market demand driven SCM disciplines of the commercial industry to a low -volume, schedule driven aerospace environment is not only possible but vital to accurately estimate, plan, control and manage the non -recurring and recurring costs assoc iated with long -term operations and vehicle processing of space f light and ground support e quipment . Applying th ese discipline s is especially crucial during the early design, development, test an d engineering (DDT&E) phase of a new program. Upwards of 70 to 80% of the operational recurring costs , which include 90% of the indirect processing costs associated with Launch and Landing core activities, are influe nced as a result of this initial phase of the product lifecycle. Breakthroughs in the commercial field of SCM are giving top -level commercial industry operations and production managers the forecasting and integration capability needed to create a just -in - time and on -demand rapid mobilization of manufacturing sources . Comparatively , as we turn our attention to very large space endeavors , delegation of sustainment activities from the P rogram to the Project O ffices , complicates the integration and forecastin g of material and information flows , and could prevent true integration from ever being achieved . Good collaborative forecasting, planning and realistic replenishment scheduling is essential to an effective SCM practice especially , when considering simulta neous non -serial activity of diverse new programs anticipated for future Lunar and Mars expeditions .
Planning a safe and productive human space exploration mission involves a dual approach addressing both the health of the vehicle and the crew. The goal of this study was to develop a quantitative model of astronaut health during long-duration space flight and a medical supply demand model in support of such missions. The model provides two outputs, Alpha(h) and Mass of Medical Consumables (MMC), for each set of input parameters. Alpha(h) is an estimate of total crew health and is displayed as a percentage. MMC is a measure of medical consumables expended during the mission and is displayed in units of kilograms. We have demonstrated that Alpha,, is a function of three scaling parameters, the type of mission, duration of mission, and gender mix of the crew. The type of mission and gender of crew are linked to radiation fatality data published by NASA. Mission duration is incorporated into the model with predicted incidence of illness and injury data published on US Navy submarine crews. MMC increases non-linearly with the number of crew, the duration of the mission and the distance of the mission away from Earth. This article describes the relationships between these parameters and discusses implications for future crewed space missions.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2007. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Includes bibliographical references (p. 167-170). In the design of complex systems serving a broad group of stakeholders, it can be difficult to prioritize objectives for the architecture. I postulate that it is possible to make architectural decisions based on consideration of stakeholder value delivery, in order to help prioritize objectives. I introduce the concept of value network models to map out the indirect benefit delivered to stakeholders. A numerical methodology for prioritizing paths through this network model is presented, with a view to discovering the most important organizational outputs. I show how value network models can be linked to architecture models to provide decision support to the architect. I present a case study to examine the connectivity and sensitivity of a test architecture to value delivery. I conclude that a limited subset of NASA's outputs will discriminate between architectures. In this manner, I show how value considerations can be used to structure the design space before critical technical decisions are made to narrow it. A number of organizational implications for value delivery are generated from this analysis. In particular, I show that benefit flows should be aligned to organizational processes and responsibilities, and that failure to map stakeholder input to architecture evaluation can weaken benefit. by Bruce G. Cameron. S.M.
As NASA prepares to establish a manned outpost on the lunar surface, it is essential to consider the logistics of both the construction and operation of this outpost. This thesis presents an interplanetary supply chain management and logistics planning and simulation software tool, SpaceNet, developed to assist mission architects, planners, systems engineers and logisticians in performing analysis on what will be needed to support future human exploration missions, primarily in the Earth-Moon-Mars system. Also presented in this thesis are the results of numerous trade studies performed using SpaceNet to determining the best mix of mission types (pre-positioning, carry-along and resupply) to achieve sustainable, robust space exploration. These trade studies focus on analyzing notional mission architectures in terms of scientific benefit, logistical overhead and robustness to campaign level risks such as flight delays, flight cancellations and uncertain demand parameters. The significant findings presented in this thesis broadly fall into three categories: a demonstration of the value of integrated modeling and simulation of campaign logistics, the best logistics strategy for the establishment of a lunar outpost, and suggestions to reduce campaign level risk.
The objective of this paper is to demonstrate a methodology for designing and evaluating the operational planning for interplanetary exploration missions. A primary question for space exploration mission design is how to best design the logistics re- quired to sustain the exploration initiative. Using terrestrial logistics modeling tools that have been extended to encompass the dynamics and requirements of space trans- portation, an architectural decision method has been created. The model presented in this paper is capable of analyzing a variety of mission scenarios over an extended period of time with the goal of defining interesting mission architectures that enable space logistics. This model can be utilized to evaluate different logistics trades, such as a possible establishment of a push-pull boundary, which can aid in commodity pre- positioning. The model is demonstrated on an Apollo-style mission to both provide an example and validate the methodology.
The objective of this paper is to demonstrate a methodology for designing and evaluating the operational planning for interplanetary exploration missions. A primary question for space exploration mission design is how to best design the logistics required to sustain the exploration initiative. Using terrestrial logistics modeling tools that have been extended to encompass the dynamics and requirements of space transportation, an architectural de- cision method has been created. The model presented in this paper is capable of analyzing a variety of mission scenarios over an extended period of time with the goal of deflning in- teresting architectural scenarios for space logistics. This model can be utilized to evaluate difierent logistics trades, such as a possible establishment of a push-pull boundary, which can aid in commodity pre-positioning. The results of this implementation are presented for a lunar campaign using estimated surface demands for exploration.
One of the major logistical challenges in human space exploration is asset management. This paper presents observations on the practice of asset management in support of human space flight to date and discusses a functional-based supply classification and a framework for an integrated database that could be used to improve asset management and logistics for human missions to the Moon, Mars and beyond.
Mission planners for future human space exploration enterprises face several challenges in the area of operations, including coordinating the logistics and resupply of far-flung planetary bases. A number of logistics methods have been perfected by commercial and military experts, but these are not well understood in the context of space exploration. This paper describes a field expedition to a Mars analog site in the high Arctic, at which terrestrial logistics methods were tested in the context of (analog) planetary exploration. A comprehensive comparison is drawn between the logistics scenarios at HMP and a potential lunar or Mars base, in order to determine the extent of the analogy between them. It appears that the analogy is quite good in certain categories of supplies and shipment, but breaks down in others. When certain straightforward differences are accounted for, the data gathered from HMP can be used to validate and inform planetary base logistics models in support of future human lunar and Mars exploration.
I consider the problem of choosing index numbers of purchasing power and real income for international comparisons. I show that the desirable properties of methods based on the Fisher "Ideal" index do not extend to multilateral comparisons, except when tastes are homothetic. By contrast, the Geary method, which underlies the Penn World Tables, provides an approximation to a set of "true" exchange rate indexes which have many desirable properties. In particular, if demands exhibit generalized linearity, the true indexes measure real incomes relative to a hypothetical country whose income is an appropriate average of individual countries' incomes.
Measures of Effectiveness for SpaceNet
- O De Weck
- M Silver
- R Shishko
O. de Weck, M. Silver, and R. Shishko, "Measures of Effectiveness for SpaceNet." Unpublished, v3.3, Mar 17,
2006.
A Modeling Framework for Sustainable Space Logistics: Results and Recommendations
- S Shull
- E Gralla
- O De Weck
S. Shull, E. Gralla, and O. de Weck, "A Modeling Framework for Sustainable Space Logistics: Results and
Recommendations." accepted at the International Astronautical Congress, Valencia, Spain, Oct 2006.
11. "NASA's Exploration Systems Architecture Study," NASA-TM-2005-214062, Nov 2005.
Remote Terrestrial Sites as Operational/Logistics Analogs for Moon/Mars Bases: the Haughton-Mars Project
- E Gralla
- S Shull
- M Silver
- J Ahn
- A Siddiqi
- O De Weck
E. Gralla, S. Shull, M. Silver, J. Ahn, A. Siddiqi, O. de Weck, "Remote Terrestrial Sites as
Operational/Logistics Analogs for Moon/Mars Bases: the Haughton-Mars Project." AIAA 2006-5659,
SpaceOps 2006, Rome, Italy, 19-23 Jun 2006.