1. Requirements

6.3.6 The NASA Headquarters' Office of the Chief Engineer shall review and have concurrence approval when a Center defines subsets of requirements denoted by "P (Center)" in the Requirements Mapping Matrix in Appendix D for the indicated classes of software.

1.1 Notes

NPR 7150.2, NASA Software Engineering Requirements, does not include any notes for this requirement.

1.2 Applicability Across Classes

This requirement applies to all classes and safety criticalities.




2. Rationale
In recognition of differences among projects and Centers, NPR 7150.2 allows flexibility in the implementation of many of its requirements.  These SWEs are marked as P (Center) in NPR 7150.2, Appendix D, Requirements Mapping Matrix. "P (Center)" can be conventionally read as "partial, Center determined". See SWE-140 for guidance on two methods for developing approved subsets of these requirements.
The Office of the Chief Engineer (OCE) maintains the review and concurrence approval of acceptable partial requirement sets at the Centers for the following reasons:
  • To monitor and control the use of NASA engineering policy.
  • To maintain periodic oversight of compliance with engineering requirements throughout the Agency and its contractor community.
  • To gain or give insight into appropriate partial implementations.
The flexibility provided by locally designated subsets of Agency software requirements enables tailoring of these requirements based on results of acceptable risks versus resources trades that are to be performed by Center engineering organizations or the Engineering TA (Technical Authority).

3. Guidance
NPR 7150.2 provides basic rules for the implementation of the P (Center) concept but delegates the development of the actual approach and process steps down to each Center.  Because of this delegation, Centers are able to develop subsets of requirements using the P (Center) approach that result in local adaptations to suit Center- and application-unique needs. This general approach assures that Centers develop the requirements for their systems and work products to match the goals and objectives of their programs and projects. Centers are free to choose an approach that works best for their projects and applications. (See SWE-140 in this Handbook for guidance on two different approaches.)
The Headquarters' OCE will review each Center's P (Center) approach and documentation during periodic surveys conducted at the Center. These Center surveys are nominally scheduled for every other year. (See SWE-129 for guidance on the OCE survey process for both Headquarters and Center personnel.) Concurrence by the OCE on the Center's approach and documentation occurs in the same time frame as the survey.

 Non-concurrences by the OCE, which may occur, will be based on an OCE judgment that the Center's approach fails to meet the intent of a requirement subset from NPR 7150.2 or if it insufficiently addresses safety and/or prudent risk considerations.  In the event of a non-concurrence on the P (Center) approach and/or the non-null set requirements subset, the Center software point of contact (POC) and the OCE Survey Lead are to develop an action plan to resolve the issues related to the non-concurrence by the OCE. However, the Headquarters' OCE may review an individual project's compliance matrix and specific implementation of P (Center) requirements outside of these periodic surveys.

Each Center's Engineering Technical Authority Implementation Plan or its Software Requirements Procedure typically details the chosen approach for developing the software P (Center) requirements.

4. Small Projects
The flexibility inherent in the P (Center) requirement statement can help small projects address the need to tailor software requirements. With respect to documentation, Centers can choose to significantly lighten the documentation requirements in Chapter 5 of NPR 7150.2 for small projects.

5. Resources


6. Lessons Learned
There are currently no Lessons Learned identified for this requirement.