Certification of Core Flight Software (cFS) for NASA's Gateway Program
The project aims to certify the Core Flight Software (cFS) for NASA's Gateway program, ensuring safety-critical flight software for Gateway's modules. The certification work is led by a dedicated team, enabling cost savings across the program. The goal is to deliver a class-A certified cFS bundle while maintaining reusability and configurability characteristics. Various components are included in the certification process to meet NASA's highest certification level standards.
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2012 Flight Software Workshop February 8-11, 2021 NASA Class A Certification of Core Flight Software (cFS) Tam Ngo / Software Manager NASA/Johnson Space Center Software, Robotics & Simulation Division Spacecraft Software Engineering Branch / ER6
Outline Why we are doing this What is our goal The cFS bundle we are certifying SW requirements, standards & processes we must comply with Certification activities we plan to perform Certification artifacts we plan to produce Our 2021 delivery milestones Questions & answers 2
Why we are doing this Core Flight System (cFS) has gained tremendous popularity within the NASA software community, as well as the open source community, for its flight heritage and for its highly re-useable & re-configurable characteristics. Due to the successes, in terms of both cost & schedule, of many NASA flight projects that use cFS as its software framework, one of NASA s newest programs, Gateway, has decided to adopt cFS as part of its level-2 software commonality/portability requirements. https://www.nasa.gov/gateway These requirements are levied on all Gateway s modules, both US and International Partners. Gateway level-2 organization has funded the certification of cFS products as class A, safety- critical flight software for Gateway. The CFS certification works are being done by the same cFS team (GSFC+JSC) that develops & maintains those cFS products under the Advanced Exploration System (AES) Avionics & Software (A&S) funding for many years. Having one group responsible for the certification of the cFS products for all Gateway modules means cost saving across the Gateway program. 3
What is our goal The goal of the cFS certification project is to deliver to Gateway a cFS bundle that is class-A certified on 2 Gateway-selected platforms and class-A certifiable on other platforms. Class A, safety-critical software certification is the highest certification level defined by NASA NPR 7150.2. Certifiable software comes with all the necessary certification artifacts, test suites & tools that can be used to formally verify/certify on a specific hardware & operating system. Projects are provided with all the necessary artifacts & software to perform cFS certification with their particular hardware & software configurations. This makes it easy for a project to update & certify selected cFS products on their target platforms. Certified software is software that has been formally verified & certified on a specific hardware & operating system with all the necessary certification artifacts resulted from performing the certification. Caveat: Any changes in the code and/or its configuration or the platform configurations that were used for the official run-for-record will break the certification seal. 4
The cFS bundle we are certifying GSFC Team JSC Team Core Flight Executive (cFE) vxWorks6.9 SP0 PSP Linux PSP OS Abstraction Layer (OSAL) for vxWorks 6.9 OS Software Bus Network for Gateway (SBNg) cFS Test Framework (CTF) tool CFDP File Transfer (CF) elf2cfetbl tool Time-Triggered Scheduler (SCH_TT) TrickCFS tool Checksum (CS) Time-Triggered Ethernet library (TTE_LIB) cFS Command & Data Dictionary (CCDD) tool Data Storage (DS) File Manager (FM) Time-Triggered Ethernet Manager (TTE_MGR) Housekeeping (HK) Health & Safety (HS) Command Ingest (CI) Limit Checker (LC) Telemetry Output (TO) Memory Dwell (MD) Input/Output library (IO_LIB) Memory Manager (MM) Stored Command (SC) Framework components Applications Tools Non-certified supporting apps/tools needed for certification work 5
SW requirements, standards & processes we must comply with For certification of class A, safety-critical flight code, we are complying to the following NASA requirements, standards & processes: NPR-7150.2C Software Engineering Requirements NPR 7150.2 establishes the engineering requirements that apply to the complete software development life cycle, including software planning, development, testing, maintenance, retirement, operations, management, acquisition & assurance activities. NASA-STD-8739.8A Software Assurance & Software Safety Standards Monitored by the project s Safety & Mission Assurance (S&MA) representative Performed by the Independent Verification & Validation (IV&V) organization JSC EA-WI-35 Software Project Management & Development JSC Engineering Directorate Work Instruction that establishes the processes & work product templates necessary for developing software products adhering to NPR 7150.2 requirements. Spacecraft Software Engineering Team (SSET) policies & plans Based on the Capability Maturity Model Integration (CMMI) v2.0 model for Maturity Level 3 6
Certification activities we plan to perform Formal peer reviews, per cFS product Requirements & design Code inspection Test procedures, test methods & verification methods Static code analyses, per cFS product Part of merge request procedure from code updates Independent analyses performed by the IV&V organization Other analyses performed by the IV&V organization, per cFS product Requirement coverage analyses Verification coverage analyses Hazardous & safety analyses Unit tests and code coverage, per cFS product All unit tests must passed or documented justifications for each failed test case. 100% Condition/Decision Code coverage Cyclomatic complexity should be 15 or less. Verification testing against requirements, per cFS product CTF tool is used to create & run JSON test scripts. ( https://github.com/nasa/ctf ) CTF test runs can be automated & scheduled. Validation with vertical integration testing, per cFS build Run-for-record on selected platforms with S&MA in-the-loop for sign-off 7
Certification artifacts we plan to produce Software Requirement Specifications (SRS) document Software Detailed Design (SDD) document Peer Review Metric Reports Requirements, design, code & tests Analysis Reports Static code analyses, coverage gap analyses, safety analyses, etc. Unit tests and Code Coverage Test procedure, test code & expected test results Verification & Validation Test tool, test procedure, test scripts & expected test results Version Description Document (VDD) Including list of changes & open defects Developer s Guide Requirement Traceability Matrix Requirement to code, to test cases, to verification methods Targeted for the open source distribution 8
Our 2021 Delivery Milestones August 2021 Delivery of the certified cFS Caelum bundle on the 2 Gateway-selected platforms to Gateway HALO Production Office. September 2021 Delivery of the certifiable cFS Caelumn bundle to Gateway level-2 organization. TBD Certifiable cFS Caelum bundle available on github for the open source community https://github.com/nasa/cfs 9
