Recent years have seen a push to use explicit consideration of "value" in order to drive design. This paper conveys the need to explicitly align perspectives on "value" with the method used to quantify "value." Various concepts of value are introduced in the context of its evolution within economics in order to propose a holistic definition of value. Operationalization of value is discussed, including possible assumption violations in the aerospace domain. A series of prominent Value-Centric Design Methodologies for valuation are introduced, including Net Present Value, Multi-Attribute Utility Theory, and CostBenefit Analysis. These methods are compared in terms of the assumptions they make with regard to operationalizing value. It is shown that no method is fully complete in capturing the definition of value, but selecting the most appropriate one involves matching the particular system application being valued with acceptable assumptions for valuation. Two case studies, a telecommunications mission and a deep-space observation mission, are used to illustrate application of the three prior mentioned valuation methods. The results of the studies show that depending on method used for valuation, very different conclusions and insights will be derived, therefore an explicit consideration of the appropriate definition of value is necessary in order to align a chosen method with desired valuation insights.
Fractionated spacecraft consist of physically independent, "free-flying" modules composed of various subsystems. Thus, a fractionated spacecraft might consist of one module responsible for power generation and storage, another module responsible for communications, another module responsible for the payload, and so on. Fractionated spacecraft are of particular interest for pointing-intensive, remote sensing missions because of their ability to physically decouple subsystems and payloads that truly need precise pointing, thereby potentially enabling fractionated spacecraft to have a lesser lifecycle cost than that of a comparable monolithic spacecraft. This research seeks to explore this hypothesis and others by quantitatively assessing the impacts of various fractionated spacecraft architecture strategies on the lifecycle cost and mass of pointing-intensive, remote sensing mission spacecraft. A dynamic lifecycle simulation and parametric model was used to assess the lifecycle cost impacts, while the mass impacts were assessed using a nonparametric, physics-based computer model. Results from this research demonstrate that relative to a comparable monolithic spacecraft, fractionated spacecraft can have a lesser lifecycle cost but are always more massive. omenclature ADS_G S = attitude determination system and guidance navigation system Arch = spacecraft architecture Comm_CS_C&DH = communications, computer system, and command & data handling LCC = lifecycle cost MCA = Monte Caro Analysis (Simulation) RE = nonrecurring Power = power generation and storage RE = recurring RSM(s) = remote sensing mission(s) SET = Spacecraft Evaluation Tool S/C-G = spacecraft-to-ground
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