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01. Welcome
12. SWEHB Introduction
23. Title Material
34. Resources
45. Accessing Other Versions of SWEHB


Welcome to the NASA Software Engineering and Assurance Handbook. This wiki based Handbook provides users and practitioners with guidance material for implementing the requirements of NPR 7150.2, NASA Software Engineering Requirements and the implementation of the NASA Software Assurance and Software Safety requirements in NASA-STD-8739.8. Use of this handbook is intended to provide "best-in-class" guidance for the implementation of safe and reliable software in support of NASA projects. The handbook is a key component of an Agency-wide plan to work toward a continuous and sustained software engineering and software assurance process and product improvement.

The Handbook is designed for the community that is involved in the acquisition, management, development, assurance, maintenance, and operations of NASA software. Readers can use it to sharpen their skills in specific areas or suggest valuable guidance for others in the NASA software community. Novice and experienced software team members can use the Handbook as an easily accessible reference or manual that captures the broad knowledge base of numerous experts who have extensive experience in all aspects of NASA's software systems.

In the handbook you will see information for determining the scope and applicability of the individual NASA Software Engineering Requirements, NPR 7150.2. You will also see the rationale behind the requirements, guidance on their implementation, the specific tools that were used in the development of NASA software, pointers to key lessons learned, and select references for further information.

The handbook was developed using a "wiki" approach. You can submit any inputs and suggestions via "Feedback" in the NASA Technical Standards System (NTSS) at

We hope you will find the information helpful in your day-to-day quest for engineering excellence. It has been provided by many contributing experts, distilled into useful chunks by the NASA software community team.

Three version of the handbook are available for use (see Tab 5 . to access other access the versions of handbook)

  • Original version of the handbook - addresses the NASA Software Engineering Requirements in NPR7150.2A. NPR 7150.2A had a effective date of November 19, 2009 to the expiration date of November 19, 2014.
  • Revision A - addresses the NASA Software Engineering Requirements in NPR7150.2B. NPR 7150.2B had a effective date of November 19, 2014 to the expiration date of August 2, 2019.
  • Draft Revision B - addresses the NASA Software Engineering Requirements in NPR7150.2C. NPR 7150.2C had a effective date of August 2, 2019 to the expiration date of August 2, 2024.

NPR 7150.2C is the latest version of the NASA Software Engineering Requirements.

Note: Draft Revision B of the handbook is in the final review stage, the handbook revision B is currently being reviewed by the NASA Technical Standard Panel review process and the NASA Software Assurance and Software Safety requirements, NASA-STD-8739.8 currently being reviewed by the OSMA review process.  Once the two reviews are completed the Revision B of the software handbook will be baselined.



The NASA Software Engineering Handbook originated from multiple requests for additional guidance, rationale, resources, references and lessons learned for acquiring, managing, developing, assuring and maintaining NASA software systems. The design of the electronic (wiki-based) format was selected to accommodate the following evolving needs:

  • To publish material in a timely fashion.
  • To provide needed information in concise screen-friendly chunks.
  • To simplify updates to the Handbook.
  • To make it easily searchable.
  • To engage the NASA software community by providing an easy-to-use vehicle for
    • sharing examples of best practices, and
    • contributing lessons learned developed on their own projects.

The handbook is accessible via, the NASA Technical Standard site, or on the NASA Engineering Network (NEN).  Numerous important links are also provided for relevant processes, templates, and tools in the Software Processes Across NASA (SPAN) repository, accessible only to NASA users from the SPAN tab in this Handbook.

The handbook wiki can be used in a similar manner to the use of hard copy guidebooks, but it offers significant advantages for the reader. Once a general familiarity with the resource is obtained, the user will be able to directly access concise information relevant to their interest or need. (Typically a quick scan and flip through the Handbook structure, including the chapter organization and the reference/appendix material, is enough to gain familiarity.)

The handbook provides guidance associated with each SWE (Software Requirement) in NPR 7150.2, guidance in the form of features and topics, and software assurance and software safety requirements and guidance information. Users are expected to consult NASA Center resources for local procedures and guidance, when available.


For NASA users, the Software Engineering Handbook is available on the NEN from the Software Engineering Community of Practice homepage. This site offers additional guidance and information to software developers, including the Ask an Expert pick, a Contact List, a Document Repository, and much more. Frequent users may wish to add a direct bookmark to the SWEHB in their browser <>.

Here's an overview of each major section within the SWEHB:

  • A contains the Introduction.
  • B contains the developed guidance for each institutional requirement in NPR 7150.2. These SWE descriptions are from Chapter 2 of NPR 7150.2. The handbook was written so that each SWE guidance section provides stand-alone explanations and interpretive information about the implementation of requirement. To enhance the usefulness of each module, the guidance includes hyperlinks for easy reference to related SWEs and Topics.
  • C contains the developed guidance for each software project requirement in NPR 7150.2. (Note that the SWE descriptions are organized into three chapters that mirror the organization of NPR 7150.2).  The SWEHB was written so that each SWE guidance section provides a stand-alone explanation and interpretive information about the implementation of the requirement. To enhance the usefulness of each module, the guidance includes hyperlinks for easy reference to related SWEs and Topics. Each requirement in C also contains the software assurance steps and software safety requirements and guidelines.
  • D contains special Topics, most in the form of essays, that are broader than any single SWE. Many of the special Topics take the form of "how to" and instructional material for users seeking to improve their knowledge and practices in software engineering, software assurance and software safety. It is expected that the special Topics will help the user go beyond the minimum descriptions presented in each SWE. Topics are more expansive on particular ideas and contain additional instructions for developing and acquiring software.
  • E contains a list of terms including acronyms and/or definitions that are used in the Handbook, listings of and references to software development tools that are used around the Agency, and a complete listing of Handbook references in a numerated References Table.
  • F is a link to the Software Processes Across NASA (SPAN) repository accessible to NASA users only. This repository contains processes and process assets approved for use across the Agency.

Explanation of the SEARCH Box in the splash banner above: This utility allows the SWEHB user to interrogate the Handbook contents for particular items of interest.

In the handbook each typical requirement, SWE, essay has seven sections;

  • THE REQUIREMENT: This section is a restatement of the NPR 7150.2 requirement wording, including any Notes from either the requirement paragraph itself, or any applicable note from Appendix C. This section also gives a tabular representation of the applicability to each software class

The text in this section can only be altered via an approved change request and NODIS (NASA Online Directives Information System)  update of NPR 7150.2. 

  • RATIONALE: This section provides useful information regarding the purpose of the requirement. Occasionally, historical information and/or references are included to further support the rationale statement.
  • GUIDANCE: This section provides information helpful for interpreting the requirement, its scope, its relationship to other SWE, associated best practices, and references to supporting materials (standards, guides, published technical papers, the NEN and SPAN materials).
  • SMALL PROJECTS: This section suggests implementation aids to small projects to help satisfy the SWE while accommodating the typically limited resources of time, funds, and personnel. The definition of "small project" needs to be determined by the user.

This determination does not relieve a project from satisfying the requirements in the NPR. When small projects need to reduce the set of applicable software requirements due to constraints, the designated Center Software Technical Authority is to be consulted. Tailoring of the NASA Software Engineering requirements are broadly covered in NPR 7120.5. NASA Chief Engineer’s specific direction on tailoring and Technical Authority is located on the NEN.

  • RESOURCES: This section provides a listing of referenced and footnoted texts, documents found within publicly accessible NASA repositories and/or out on the web, and other useful documents (e.g., checklists and/or templates). It is instructive to note that the Handbook authors also included in the Resources sections listings of what might be best described as "additional reading", i.e., useful items not specifically cited or linked to in the GUIDANCE section, but thought by the authors to contain educational or expanded discussions of the ideas covered in the SWE write-up. Also, this section usually includes a separate table listing of tools, items that will help the user satisfy the requirement (e.g., developer tools). The Handbook wiki links SWEs and tools through the use of a master Tools table. The Tools table provides web sites for accessing the tool. It also lists Center(s) that currently use the tool in case the reader wants to seek out the "experiences" of a current user of the tool. Readers are invited to submit their tools for candidate inclusion in the Tools table for the benefit of others around the Agency.
  • LESSONS LEARNED (LL): This section contains references to the experiences of others involved in NASA software development activities as well as other industry and government development efforts. The majority are catalogued in the Public Lessons Learned library 
    at the Office of the Chief Engineer (OCE). Some are derived from specialized project or Center collections as well as from reputable industry and government groups. Occasionally a lesson has only indirect applicability to the requirement. It is presented as a related lesson that can be applied to help understand the content of the SWEHB.
  • SOFTWARE ASSURANCE: This section contains the software assurance and software safety steps and requirements needed to assure each engineering requirement, the software assurance and software safety products required for each requirement, the software assurance and software safety metrics required for each requirement, and the software assurance and software safety guidance associated with each software assurance and software safety step and requirement.

Remember that the NPR 7150.2 is a requirements document. It uses "shall" exclusively to indicate requirements. Applicability of a NPR 7150.2 requirement is determined by NASA Software Classification and the matrix in Appendix C (of the NPR). The handbook is not a requirements document, only an informational document.

Earlier versions of NPR 7150.2 made extensive use of the NPR's Notes sections to help with the interpretation of the SWE. This Handbook is intended to collaborate with and to augment the current NPR's Notes, and to include valuable guidance from previous versions of NPR 7150.2.

The Requirements Mapping Matrix (RMM) in NPR 7150.2 provides a list of the applicability of each software project requirement by the class of software being developed. Associated with many of the entries in the RMM are one or more notes that modify the applicability of the requirement for a particular class. Since the handbook makes explicit mention of these modifiers in section 1 of the guidance for each requirement, SWE, an additional explanation for the modifiers is included here:

  • The "X" notation signifies that the full requirement (assuming "no exceptions") is invoked by NPR7150.2 for that class of software. Note that requirements labeled with an "X" can still be tailored with the appropriate approvals, or otherwise affected by approved deviations and or waivers.
  • A blank or empty cell in the RMM indicates that the requirement is optional and not invoked by NPR 7150.2 for that software Class.

Some general comments:

  • Note that the SWE titles in the SWEHB may not always agree with those in the NPR. The SWEHB Development Team expanded the titles for some of the SWE to help distinguish between other similarly sounding SWE names (e.g., "bidirectional traceability").
  • See the Terms Table for a complete list of definitions of unique terms used in the SWEHB.
  • Much of the referenced material listed in the Resources section is located on the NASA Headquarters NODIS site, e.g., NPRs, NPDs;  in NTSS
    , e.g., NASA standards, IEEE standards, or in other NASA sites, e.g., materials from the OCE, Public LLs; etc. Please note that many of these Agency or Center assets are subject to scheduled updates. While we will make every effort to link to the latest versions, editions or documents, it is possible that you will discover references that have broken links or require updating. We invite the community to submit requests for information via "Feedback" at and requests for changes to the Handbook via MSFC Form 4657, Change Request for a NASA Engineering Standard.
  • Extensive citations are also made to external sites and to general web-hosted sites. While attempts were made to cite publicly available (i.e., "free") references, there may be an occasional reference that suggests the reader "buy" a copy. If you come across one of these, and you are a NASA user, try to access it through the NASA Technical Standards
    site. This NASA site provides prepaid access to many external repositories through an Agency-wide agreement with the site.
  • (Caveat: Since the web is a dynamic place, some references in the Resources section of the SWE may have been discontinued online or moved to another host by their owners.  While all references have been verified on internal Agency networks as well as external Virtual Private Network (VPN) access, the variances in firewall and VPN settings, permissions, and configurations may affect access to these references.)

Title Material


National Aeronautics and Space Administration

Washington, DC  20546-0001

NASA Software Engineering Handbook


Approved: 2017-01-13

Superseding NASA-HDBK-2203



Document Revision

Approval Date





Initial Release



Handbook updated to address the NASA Software Engineering Requirements, NPR 7150.2B, changes.  Update the guidance topics.

Revision B (DRAFT) TBDHandbook updated to address the NASA Software Engineering Requirements, NPR 7150.2C, changes.  Update the guidance topics.


This NASA Technical Handbook is published by the National Aeronautics and Space Administration (NASA) as a guidance document to provide engineering information; lessons learned; possible options to address technical issues; classification of similar items, materials, or processes; interpretative direction and techniques; and any other type of guidance information that may help the Government or its contractors in the design, construction, selection, management, support, or operation of systems, products, processes, or services.

This NASA Technical Handbook is approved for use by NASA Headquarters and NASA Centers and Facilities.  It may also apply to the Jet Propulsion Laboratory and other contractors only to the extent specified or referenced in applicable contracts.

This wiki-based NASA Technical Handbook provides users and practitioners with guidance material for implementing the requirements of NPR 7150.2, NASA Software Engineering Requirements. Use of this Software Engineering Handbook (SWEHB) in intended to provide "best-in-class" guidance for the implementation of safe and reliable software in support of NASA projects. This SWEHB is a key component of the NASA Software community implementation of an Agency-wide plan to work toward a continuous and sustained software engineering and software assurance process and product improvement.

Requests for information should be submitted via "Feedback" the at Requests for changes to this NASA Technical Handbook should be submitted via MSFC Form 4657, Change Request for a NASA Engineering Standard.

Ralph R. Roe, Jr 
NASA Chief Engineer

Approval Date:





The version of the handbook that you are viewing is noted in the header image. Clicking on this image while in any page of the SWEHC will take you back to the Introduction page for this version.

To access other versions of the Software Engineering Handbook use the links below: