Message Abstraction Layer - Service Layering

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.