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The Spacecraft Monitoring & Control (SM&C) Working Group of the Consultative Committee for Space Data Systems ((CCSDS )), which sees the active participation of 10 space agencies and of the Space Domain Task Force of the Object Management Group ((OMG )), is defining a service-oriented architecture consisting of a set of standard end-to-end services between functions resident on board a spacecraft or based on the ground, that are responsible for mission operations. The CCSDS Message Abstraction Layer (MAL) provides message abstraction and generic service patterns to the Mission Operation (MO) services defined in the CCSDS Mission Operations Services Concept.〔(Mission Operations Services Concept ), CCSDS 520.0-G-3. Green Book. Issue 3. December 2010〕 == Service Layering == A key feature of the MO Service Framework〔 is the layering of services. While there are a range of potential services identified corresponding to different types of mission operations information that are exchanged within a system (status parameters, control actions, orbital data, mission timelines, etc.), these application level services are implemented in terms of a smaller set of generic interaction patterns that allow current status to be observed, operations to be invoked and bulk data transferred. This has two key benefits: it is inherently extensible, as new services can be overlaid on the existing common services; and the investment made in MO applications is further isolated from the implementation technology. Technology adapters allow the underlying communications infrastructure to be changed (or bridged) with minimal impact on the applications themselves. This improves long-term maintainability, as missions often outlive the ground technology used to deploy them initially. The layers of the Mission Operations Service Framework〔 are: * The Mission Operations (MO) Layer * The Common Services Layer * The Message Abstraction Layer (MAL) * A message transport layer The interface between each layer is defined in the CCSDS standards and therefore implementations of the each layer can be replaced without change to other software. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Message Abstraction Layer」の詳細全文を読む スポンサード リンク
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