MIT ESD 71 - Analysis of Crewed Lunar Exploration Habitation Alternatives

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I. Introduction and motivationII. Understanding the effects of uncertain project lifetimes and flight ratesIII. Understanding uncertainty in monetary value of lunar exploration 2022202320242025202620272028ENPV (Cash Flow) [$M]3337,3468,0178,1727,6596,2873,827NO FLEXIBILITY 3,8014,6665,1315,0694,3262,713Dynamic programming 1,8632,5862,9022,6851,780approach 4571,0891,3121,000(check next year) 428163347 798199 656 IV. Summary and conclusionsAcknowledgments and future project suggestionsAppendixReferencesAn Engineering Systems Analysis of Crewed LunarExploration Habitation AlternativesPrepared by:Arthur GuestESD.71 – Engineering Systems Analysis for DesignApplication PortfolioFall 2008An Engineering Systems Analysis of Crewed LunarExploration Habitation AlternativesArthur N. Guest1 Massachusetts Institute of Technology, Cambridge, MA, 02139This paper discusses various design alternative for developing and deploying lunarexploration habitats to support extended crewed missions to the Moon. The main “fixed”alternative studied includes developing a set of six interdependent habitats that, whenassembled together, can support 180-day missions, but cannot support any missions until allelements are delivered to the lunar surface. The “flexible” alternative involves developing aset of six independent habitats that can also support 180-day missions when fully assembled,but can also support shorter missions dependent on the number of habitats delivered. Thedownside to this alternative is that the habitats would be more complex and therefore moreexpensive. To test which alternative is better in the face of an uncertain future, a decisionanalysis and a lattice valuation were performed. The decision analysis shows that the flexiblealternative provides a higher expected amount of crew days when investigating the effects ofuncertain project lifetime and uncertain flight rates. However, based on a benefit-cost ratio,the fixed alternative is preferable because of the lower development costs. Focusing on thefixed alternative, the lattice valuation shows the benefits of being able to cancel the programearly because of the uncertain monetary value of a year of lunar surface exploration. With orwithout this flexibility, the development of habitats to allow extended lunar explorationappears to have a positive ENPV.Table of ContentsI. Introduction and motivation..................................................................................................................2II. Understanding the effects of uncertain project lifetimes and flight rates.....................................3III. Understanding uncertainty in monetary value of lunar exploration...........................................9IV. Summary and conclusions.............................................................................................................14Acknowledgments and future project suggestions................................................................................14Appendix..................................................................................................................................................15References.................................................................................................................................................171 Graduate Research Assistant, Department of Aeronautics & Astronautics, 33-409.Massachusetts Institute of Technology Page 1ESD.71 Engineering Systems Analysis for DesignI. Introduction and motivationN response to President G.W. Bush’s Vision for Space Exploration, NASA is planning on returning humans to thelunar surface by 2020. In contrast to the “flags-and-footprints” missions of the Apollo program, this newendeavor, entitled Constellation, focuses on having humans live and work on the lunar surface for extended periods.This objective requires several complex systems to operate together including the lunar transportation system andthe lunar surface system. One of the key components of the lunar surface system is the lunar outpost, which is madeup of a collection of habitation modules. Because these modules are critical for supporting the astronauts duringtheir extended missions on the surface of the Moon, it is important to ensure that the best configuration andimplementation plan is chosen for the habitation modules.ICurrent architectures are based around the assumption that lunar crews will operate on mission rotations ofapproximately 180 days. In order to ensure enough habitable volume and due to the mass constraints of the lunartransportation system, an outpost that supports 180-day missions will require that several habitation modules operatetogether. While there are several various designs proposed, this paper will assume that each habitation module canprovide enough habitable volume and equipment to support a crew for 30-days. Based on this assumption, sixhabitation modules will have to be delivered to the lunar surface to support 180-day missions.While there are many factors that lead into the final design of the habitation modules, this paper will focus onone factor of particular importance: the interdependence between the habitation modules. One possible design,referred to as the fixed design in this paper, is to develop a system of habitation modules that have the subsystemsand the required functionality distributed between the different modules. In this case, the six habitation modules,when assembled, will be able support a crew for 180-days, but they will not be able to support any crew before allthe modules have been delivered to the lunar surface. The advantage of this is that the complexity, and therefore thecost, of each module is assumed to be decreased due to the distribution of its internal functions. The disadvantage ofthis is that all six habitation modules have to be launched and delivered to the lunar surface before any crews can besent to explore the Moon. While it would be possible to send crewed sortie missions (i.e. missions of only a fewdays) to the lunar surface before the habitation cluster is ready, this option is not addressed in this paper.The second possible alternative for designing the habitation modules is to make each module completelyindependent, known in this paper as the flexible design. This would mean that the complete


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MIT ESD 71 - Analysis of Crewed Lunar Exploration Habitation Alternatives

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