New Products from NASA’s Software Architecture Review Board Lorraine Fesq Jet Propulsion Laboratory, California Institute of Technology Flight Software Workshop October 27-29, 2015 Johns Hopkins University/Applied Physics Laboratory Annapolis, MD Copyright 2015 California Institute of Technology. Government sponsorship acknowledged. The research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Mission & Charter of SARB SARB was established by NASA OCE in April 2009 Mission: Manage flight software complexity through better software architecture Charter Provide constructive feedback to flight projects in the formative stages of software architecting Focus on architectural improvements to reduce and/or better manage complexity in requirements, design, implementation, verification, and operations Spread best architectural practices, principles, and patterns across flight software centers Contribute to NASA Lessons Learned

NASA Software Architecture Reviews Objectives Manage and/or reduce flight software complexity through better software architecture Help improve mission software reliability and save costs Plan Prepare introductory document, review process, review checklist, documentation recommendations, and sample problem statement Educate team on process Practice on flown missions Conduct real reviews Approach Create a NASA-wide software architecture review board (SARB) Engage with flight projects in the formative stages of software architecture

SARB Team Members (as of October 2015) Name Expertise / Position Affiliation Michael Aguilar Sponsor and NESC Software Discipline Expert, NASA Technical Fellow in Software NESC Dan Dvorak SARB co-Lead, Integrated Model-Centric Engineering (IMCE) team JPL Lorraine Fesq SARB co-Lead, Fault Management Community of Practice Lead, 3101 Ken Costello Aerospace and Software engineer, IV&V Program Chief Architect IV&V Michael Madden Chief Scientist, Simulation Development and Analysis Branch LaRC Darrel Raines Orion Flight Software System Manager JSC John Weir FSW Lead for Space Launch System (and formerly, Ares I) MSFC Kathryn Weiss Senior Flight Software Engineer, JPL Flight Software Product Line Cognizant Engineer Jonathan Wilmot Software architect, Flight Software Branch GSFC

SARB Community of Practice Page https://nen.nasa.gov/web/sarb

SARB Documents Located on “Preparation for Review” page on SARB CoP Contextually Driven Architecture Reviews (outreach) Project Problem Statement template Preparing for a Software Architecture Review Reference Architecture Questions Architecture Review Checklist Scope of Architectural Concerns Quality Attributes Table https://nen.nasa.gov/web/sarb/preparation

Recommended Contents for Software Architecture Descriptions SARB advises starting with the SEI Template for a SW ADD, in conjunction with the following to address concerns/characteristics specific to the NASA FSW domain Architecture Terminology Mission Overview Context Diagram, Context Description Architectural Drivers Critical Resources & Margins Stakeholders & Concerns Quality Attribute Analysis Measures of Performance Architectural Decisions & Rationale Architectural Alternatives (Trade Studies) Multiple Views Diagrams and Legends Architectural Frameworks Heritage Analysis/Software Reuse Assumptions & Limitations Architectural Patterns, Principles, Invariants, Rules Fault Management Non-Concerns References SEI Template for Software Architecture Documentation Full document available at https://nen.nasa.gov/web/software/sarb/guidelines

SARB Documents Located on “Preparation for Review” page on SARB CoP Contextually Driven Architecture Reviews (outreach) Project Problem Statement template Preparing for a Software Architecture Review Reference Architecture Questions Architecture Review Checklist Scope of Architectural Concerns Quality Attributes Table https://nen.nasa.gov/web/sarb/preparation

Quality Attributes Table The Quality Attribute Table contains software architecture quality attributes that are relevant to the mission-critical real-time embedded systems. Full document available at https://nen.nasa.gov/web/software/sarb/preparation

Quality Attributes Table – excerpt

Quality Attributes Table Use Cases The QA Table has at least three primary use cases Use by a software architect and project team to evaluate the priorities of each QA for a specific project. Use during development – Developers implementing the architecture need to be mindful of the “Tactic to achieve”, “Evidence of/verification”, “Project Prioritization”, and “Project intended variation” columns for each attribute during the design and coding process Use in the review process to evaluate a software architecture with respect to each QA in the Table and the priorities established by the project Full document available at https://nen.nasa.gov/web/software/sarb/preparation

SARB is a NASA-provided resource SARB is available to NASA projects “Free of charge” for reviews Review feedback is provided to project only – handled confidentially/discreetly Encourage your project to conduct a software architecture review before PDR After PDR, it’s hard to make any substantive changes Inquire about a review at https://nen.nasa.gov/web/software/sarb or email Lorraine.M.Fesq@jpl.nasa.gov