Software Engineering Institute

A mission thread is a sequence of end-to-end activities and events that takes place to accomplish the execution of an SoS capability. The mission thread takes place in the context defined by a vignette, which is a short story about environment. We identify three basic types of mission threads: 1) operational, 2) development, and 3) sustainment.

The Mission Thread Workshop (MTW) is a facilitated process that brings together SoS stakeholders to augment existing mission threads with quality attribute considerations that will shape the SoS architecture and to identify SoS architectural challenges. The MTW has three phases:

In the Preparation phase, the SoS program manager develops an overview presentation on the SoS mission/business drivers, and the SoS architect develops an overview presentation on the SoS architecture plans. The facilitation team meets with the SoS program manager and architect to plan the MTW, provide feedback on the two presentations, reach agreement on mission threads and types, and identify stakeholders.

The Execution phase involves augmenting the mission threads with quality attribute considerations and identifying SoS architectural challenges based on stakeholder inputs and the dialogue between the stakeholders and the architects. During the augmentation, overarching quality attribute considerations—as well as step-specific quality attribute considerations for each quality attribute of the SoS—are elicited and documented for each mission thread. The architects can also describe how the planned architecture satisfies the quality attribute considerations in each step for each mission thread selected for the workshop.

In the third and final phase, Roll-Up and Follow-Up, two reports are produced from the activity in the execution phase, and answers to action items are assigned in that phase. One report includes the quality attribute considerations for each step of each mission thread selected for the MTW and overarching quality attribute considerations for each mission thread. The other report describes the SoS architectural challenges. At the end of the series of MTWs, an annotated summary briefing rolls up SoS architectural challenges and strengths, non-architectural issues (if any are uncovered), and recommendations.

The MTW is a prerequisite to the SEI SoS Architecture Evaluation, since its results are used in that evaluation.