Orion Entry, Descent, and Landing Performance and Mission Design

The Orion Vehicle is the next spacecraft to take humans into space and will include missions to ISS as well as missions to the Moon. As part of that challenge, the vehicle will have to accommodate multiple mission design concepts, since return from Low Earth Orbit and return from the Moon can be quite different. Commonality between the different missions as it relates to vehicle systems, guidance capability, and operations concepts is the goal. Several unique mission design concepts include the specification of multiple land-based landing sites for a vehicle with closed-loop direct and skip entry guidance, followed by a parachute descent and landing attenuation system. This includes the ability of the vehicle to accurately target and land at a designated landing site, including site location aspects, landing site size, and landing opportunities assessments. Analyses associated with these mission design and flight performance challenges and constraints will be discussed as well as potential operational concepts to provide feasibility and/or mission commonality

Guidance, Navigation, and Control System Design in a Mass Reduction Exercise

Early Orion GN&C system designs optimized for robustness, simplicity, and utilization of commercially available components. During the System Definition Review (SDR), all subsystems on Orion were asked to re-optimize with component mass and steady state power as primary design metrics. The objective was to create a mass reserve in the Orion point of departure vehicle design prior to beginning the PDR analysis cycle. The Orion GN&C subsystem team transitioned from a philosophy of absolute 2 fault tolerance for crew safety and 1 fault tolerance for mission success to an approach of 1 fault tolerance for crew safety and risk based redundancy to meet probability allocations of loss of mission and loss of crew. This paper will discuss the analyses, rationale, and end results of this activity regarding Orion navigation sensor hardware, control effectors, and trajectory design

Governing the world at a distance : the practice of global benchmarking

Benchmarking practices have rapidly diffused throughout the globe in recent years. This can be traced to their popularity amongst non-state actors, such as civil society organisations and corporate actors, as well as states and international organisations (IOs). Benchmarks serve to both ‘neutralise’ and ‘universalise’ a range of overlapping normative values and agendas, including freedom of speech, democracy, human development, environmental protection, poverty alleviation, ‘modern’ statehood, and ‘free’ markets. The proliferation of global benchmarks in these key areas amounts to a comprehensive normative vision regarding what various types of transnational actors should look like, what they should value, and how they should behave. While individual benchmarks routinely differ in terms of scope and application, they all share a common foundation, with normative values and agendas being translated into numerical representations through simplification and extrapolation, commensuration, reification, and symbolic judgements. We argue that the power of benchmarks chiefly stems from their capacity to create the appearance of authoritative expertise on the basis of forms of quantification and numerical representation. This politics of numbers paves the way for the exercise of various forms of indirect power, or ‘governance at a distance’, for the purposes of either status quo legitimation or political reform

Money for Nothing: Everyday Actors and Monetary Crises

Why do monetary unions fail? Structural approaches that focus on shifts in the distribution of capabilities ascribe non-elites limited agency to influence large-scale political and economic change. Existing agent-centred approaches tend to simplify the social dynamics of the everyday politics of money by concentrating on how elites determine formal changes within monetary systems. Answers to this question from a material-based perspective often point to a breakdown in elite political support, driven by actors’ material incentives to cheat on their multilateral commitments rather than cooperate to overcome the collective action problem that a monetary union entails. Recent ideational perspectives have focused on the role of shared economic ideas among elites, as well as elite struggles over national identity, as crucial ingredients in the construction, maintenance, or failure of a monetary union. While drawing on the insights of rationalist and constructivist theories, this article uses a historical sociology approach to argue that the everyday actions taken by non-elites as survival strategies in a monetary crisis provide an important additional ingredient for understanding monetary system change. This approach is illustrated through a case study of the collapse of the ruble zone monetary union over 1991–1993