Space Exploration Systems, Strategies and Solutions

The present thesis describes the PhD research activities dealing with the topic “Space Exploration Systems, Strategies and Solutions”. Traveling beyond low Earth orbit is the next step in the conquest of the solar system and so far, a human expedition to Mars is considered the most interesting goal of future human space exploration. Due to the technological and operational challenges associated with such a mission, it is necessary to define an opportune path of exploration, relying on many missions to intermediate and “easier” destinations, which would allow a gradual achievement of the capabilities required for the human Mars mission. The main scope of this research has been the development of a rigorous and versatile methodology to define and analyze evolutionary exploration scenarios and to provide a detailed technologies’ database, to support strategic decisions for human space exploration. The very innovative aspect of this work regards the development of a flexible methodology which can be followed to assess which are the next destinations for the exploration of space beyond LEO and to preliminarily define mission’s architectures, identifying the most significant needed elements and advanced technologies. The obtained results should be seen as a pure technical reference, as no cost and/or political considerations have been included, and can be exploited to opportunely drive the decisions of the agencies to place investments for the development of specific technologies and get ready for future exploration missions. The first part of the work has been devoted to the definition of a reference human space exploration scenario, which relies on both robotic and human missions towards several destinations, pursuing an increasing complexity approach and looking at a human expedition to Mars as final target. The scenario has been characterized through the assessment of the missions and the relative phases and concepts of operations. Accordingly, the needed space elements, or building blocks, have been identified. In this frame, the concept design of two specific elements has been performed: the first is a pressurized habitation module (Deep Space Habitat) for hosting astronauts during deep space missions; the second is an electrical propulsive module (Space Tug), mainly envisioned for satellites servicing. The last part of the work has focused on the analysis of innovative and enabling technologies, with particular attention to the aspects related to their on-orbit demonstration/validation, prior to their actual implementation in real exploration missions. The PhD has been sponsored by Thales Alenia Space - Italy and the overall work has been performed in different frameworks along the three years, as well as participating to several additional activities. In line with the objectives of the PhD, in 2012 a collaboration between Politecnico di Torino and Massachusetts Institute of Technology has been established (MITOR Project, managed by MIT-Italy Program), with the support of Thales Alenia Space as industrial partner. The MITOR project, titled “Human Space Exploration: from Scenario to Technologies”, has been aimed at identifying and investigating state of the art for Human Space Ex- ploration, enabling elements, subsystems and technologies with reference to a selected scenario and relevant missions and architectures. Part of the nine months activities has been carried out at MIT AeroAstro department. Besides MITOR project, the PhD activities have been carried out in synergy with some other research programs, such as ESA “Human Spaceflight & Exploration Scenario Studies” and STEPS2 project (Sistemi e Tecnologie per l’EsPlorazione Spaziale - phase 2). Furthermore, in 2013 a specific study has been performed in collabora- tion with university “La Sapienza” (Rome), “Osservatorio Astrofisico di Torino” (Astrophysical Observatory of Torino) and DLR (Deutsches Zentrum fr Luft- und Raumfahrt) in Bremen; its main objective has been the analysis of an interplanetary cubesats mission, aimed at space weather evaluations and technologies demonstration

Matrix Methods for Optimal Manifesting of Multinode Space Exploration Systems

http://www1.aiaa.org/content.cfm?pageid=318, Presented at the AIAA Space 2010 Conference and ExhibitionAnaheim, CA, 30 August–2 September 2010.This paper presents matrix-based methods for determining optimal cargo manifests for space exploration. An exploration system is defined as a sequence of in-space and on-surface transports between multiple nodes coupled with demands for resources. The goal is to maximize value and robustness of exploration while satisfying logistical demands and physical constraints at all times. To reduce problem complexity, demands are abstracted to a single class of resources, and one metric (e.g., mass or volume) governs capacity limits. Matrices represent cargo carried by transports, cargo used to satisfy demands, and cargo transferred to other transports. A system of equations enforces flow conservation, demand satisfaction, and capacity constraints. Exploration system feasibility is evaluated by determining if a solution exists to a linear program or network-flow problem. Manifests are optimized subject to an objective function using linear or nonlinear programming techniques. In addition to modeling the manifesting problem, a few metrics such as the transport criticality index are formulated to enable analysis and interpretation. The proposed matrix manifest modeling methods are demonstrated with a notional lunar exploration system composed of 32 transports, including eight cargo and nine crewed landings at an outpost at the lunar south pole and several surface excursions to Malapert Crater and Schrödinger Basin. It is found that carry-along and prepositioning logistics strategies yield different manifesting solutions in which transport criticality varies. For the lunar scenario, transport criticality is larger for a prepositioning strategy (mean value of 3.02), as compared with an alternative carry-along case (mean value of 1.99)

Architecting the Communication and Navigation Networks for NASA's Space Exploration Systems

NASA is planning a series of short and long duration human and robotic missions to explore the Moon and then Mars. A key objective of the missions is to grow, through a series of launches, a system of systems communication, navigation, and timing infrastructure at minimum cost while providing a network-centric infrastructure that maximizes the exploration capabilities and science return. There is a strong need to use architecting processes in the mission pre-formulation stage to describe the systems, interfaces, and interoperability needed to implement multiple space communication systems that are deployed over time, yet support interoperability with each deployment phase and with 20 years of legacy systems. In this paper we present a process for defining the architecture of the communications, navigation, and networks needed to support future space explorers with the best adaptable and evolable network-centric space exploration infrastructure. The process steps presented are: 1) Architecture decomposition, 2) Defining mission systems and their interfaces, 3) Developing the communication, navigation, networking architecture, and 4) Integrating systems, operational and technical views and viewpoints. We demonstrate the process through the architecture development of the communication network for upcoming NASA space exploration missions

Systems engineering in space exploration

Seminar on systems engineering in space exploration - systems design, systems analysis, space flight operations, and program engineering and project problem

Model Driven Mutation Applied to Adaptative Systems Testing

Dynamically Adaptive Systems modify their behav- ior and structure in response to changes in their surrounding environment and according to an adaptation logic. Critical sys- tems increasingly incorporate dynamic adaptation capabilities; examples include disaster relief and space exploration systems. In this paper, we focus on mutation testing of the adaptation logic. We propose a fault model for adaptation logics that classifies faults into environmental completeness and adaptation correct- ness. Since there are several adaptation logic languages relying on the same underlying concepts, the fault model is expressed independently from specific adaptation languages. Taking benefit from model-driven engineering technology, we express these common concepts in a metamodel and define the operational semantics of mutation operators at this level. Mutation is applied on model elements and model transformations are used to propagate these changes to a given adaptation policy in the chosen formalism. Preliminary results on an adaptive web server highlight the difficulty of killing mutants for adaptive systems, and thus the difficulty of generating efficient tests.Comment: IEEE International Conference on Software Testing, Verification and Validation, Mutation Analysis Workshop (Mutation 2011), Berlin : Allemagne (2011

How to Extend the Capabilities of Space Systems for Long Duration Space Exploration Systems

For sustainable Exploration Missions the need exists to assemble systems-of-systems in space, on the Moon or on other planetary surfaces. To fulfill this need new and innovative system architecture is needed that can be satisfied with the present lift capability of existing rocket technology without the added cost of developing a new heavy lift vehicle. To enable ultra-long life missions with minimum redundancy and lighter mass the need exists to develop system soft,i,are and hardware reconfigurability, which enables increasing functionality and multiple use of launched assets while at the same time overcoming any components failures. Also the need exists to develop the ability to dynamically demate and reassemble individual system elements during a mission in order to work around failed hardware or changed mission requirements. Therefore to meet the goals of Space Exploration Missions in hiteroperability and Reconfigurability, many challenges must be addressed to transform the traditional static avionics architecture into architecture with dynamic capabilities. The objective of this paper is to introduce concepts associated with reconfigurable computer systems; review the various needs and challenges associated with reconfigurable avionics space systems; provide an operational example that illustrates the needs applicable to either the Crew Exploration Vehicle or a collection of "Habot like" mobile surface elements; summarize the approaches that address key challenges to acceptance of a Flexible, Intelligent, Modular and Affordable reconfigurable avionics space system

Artificial table testing dynamically adaptive systems

Dynamically Adaptive Systems (DAS) are systems that modify their behavior and structure in response to changes in their surrounding environment. Critical mission systems increasingly incorporate adaptation and response to the environment; examples include disaster relief and space exploration systems. These systems can be decomposed in two parts: the adaptation policy that specifies how the system must react according to the environmental changes and the set of possible variants to reconfigure the system. A major challenge for testing these systems is the combinatorial explosions of variants and envi-ronment conditions to which the system must react. In this paper we focus on testing the adaption policy and propose a strategy for the selection of envi-ronmental variations that can reveal faults in the policy. Artificial Shaking Table Testing (ASTT) is a strategy inspired by shaking table testing (STT), a technique widely used in civil engineering to evaluate building's structural re-sistance to seismic events. ASTT makes use of artificial earthquakes that simu-late violent changes in the environmental conditions and stresses the system adaptation capability. We model the generation of artificial earthquakes as a search problem in which the goal is to optimize different types of envi-ronmental variations

Experiences applying Formal Approaches in the Development of Swarm-Based Space Exploration Systems

NASA is researching advanced technologies for future exploration missions using intelligent swarms of robotic vehicles. One of these missions is the Autonomous Nan0 Technology Swarm (ANTS) mission that will explore the asteroid belt using 1,000 cooperative autonomous spacecraft. The emergent properties of intelligent swarms make it a potentially powerful concept, but at the same time more difficult to design and ensure that the proper behaviors will emerge. NASA is investigating formal methods and techniques for verification of such missions. The advantage of using formal methods is the ability to mathematically verify the behavior of a swarm, emergent or otherwise. Using the ANTS mission as a case study, we have evaluated multiple formal methods to determine their effectiveness in modeling and ensuring desired swarm behavior. This paper discusses the results of this evaluation and proposes an integrated formal method for ensuring correct behavior of future NASA intelligent swarms

Simulating Operational Concepts for Autonomous Robotic Space Exploration Systems: A Framework for Early Design Validation

During mission design, the concept of operations (ConOps) describes how the system operates during various life cycle phases to meet stakeholder expectations. ConOps is sometimes declined in a simple evaluation of the power consumption or data generation per mode. Different operational timelines are typically developed based on expert knowledge. This approach is robust when designing an automated system or a system with a low level of autonomy. However, when studying highly autonomous systems, designers may be interested in understanding how the system would react in an operational scenario when provided with knowledge about its actions and operational environment. These considerations can help verify and validate the proposed ConOps architecture, highlight shortcomings in both physical and functional design, and help better formulate detailed requirements. Hence, this study aims to provide a framework for the simulation and validation of operational scenarios for autonomous robotic space exploration systems during the preliminary design phases. This study extends current efforts in autonomy technology for planetary systems by focusing on testing their operability and assessing their performances in different scenarios early in the design process. The framework uses Model-Based Systems Engineering (MBSE) as the knowledge base for the studied system and its operations. It then leverages a Markov Decision Process (MDP) to simulate a set of system operations in a relevant scenario. It then outputs a feasible plan with the associated variation of a set of considered resources as step functions. This method was applied to simulate the operations of a small rover exploring an unknown environment to observe and sample a set of targets