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NPR 8705.5A
Effective Date: June 07, 2010
Cancellation Date: December 09, 2022
Responsible Office: GA

Technical Probabilistic Risk Assessment (PRA) Procedures for Safety and Mission Success for NASA Programs and Projects (w/Change 2)


Cancellation Notice

Responsible office requested the directive remain effective until February 28, 2023 to allow employees an opportunity to read the cancellation notice that list documents for which different sections of this directive were moved.

Agency-level requirements in this NPR are being cancelled consistent with the policy direction to be more objectives-driven as defined in NPD 8700.1F, NASA Policy for Safety and Mission Success. The intent of this NPR is achieved through other Agency directives and practices. Programs and projects may still be expected to conduct probabilistic risk assessments in the service of compliance with other directives and standards such as NPR 8705.2, Human-Rating Requirements for Space Systems, NPR 8000.4, Agency Risk Management Procedural Requirements, and NASA-STD 8729.1, NASA Reliability and Maintainability Standard for Spaceflight and Support Systems.

Programs and projects will continue to implement obligations under existing plans, contracts, and other agreements at the time of cancellation of this NPR unless determined otherwise with concurrence from the relevant Safety and Mission Assurance Technical Authorities.

Accepted standards and guidance for the conduct of PRA include ISO 11231:2019, Space systems — Probabilistic risk assessment (PRA), and NASA/SP-2011-3421, Probabilistic Risk Assessment Procedures Guide for NASA Managers and Practitioners. Technical authorities may accept other standards for use by programs and projects.

Change History

Table of Contents

P.1 Purpose
P.2 Applicability
P.3 Authority
P.4 Applicable Documents and Forms
P.5 Measurement/Verification
P.6 Cancellation

Chapter 1. Introduction

1.1 Background
1.2 PRA Characteristics

Chapter 2. PRA Process

2.1 Overview
2.2 Definition of PRA Objective(s)
2.3 PRA Requirements
2.4 Scenario Development
2.5 Quantification and Uncertainty
2.6 Interpretation of the PRA Result
2.7 PRA Documentation
2.8 PRA Quality

Chapter 3. PRA Scope and Level of Detail

3.1 Overview
3.2 Program Life-Cycle Phases
3.3 Application of PRA to Support Decisions

Chapter 4. Roles and Responsibilities

4.1 Overview
4.2 Mission Directorate Associate Administrators
4.3 Chief, Safety and Mission Assurance
4.4 Center Directors
4.5 Center Safety and Mission Assurance (SMA) Directors
4.6 Program/Project Managers
4.7 Program/Project PRA Lead

Chapter 5. Independent Peer Reviews (IPR)

5.1 Overview
5.2 IPR Authority

Appendix A. Acronyms
Appendix B. References
Appendix C. Comments on PRA Scope


This Document is Obsolete and Is No Longer Used.
Check the NODIS Library to access the current version: