NASA Procedures and Guidelines
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NPR 8705.2 Eff. Date: June 19, 2003 Cancellation Date: February 07, 2005	Human-Rating Requirements and Guidelines for Space Flight Systems w/Change 2 (6/25/04)
| TOC | Change | Preface | Chapter1 | Chapter2 | Chapter3 | AppendixA | AppendixB | AppendixC | AppendixD | AppendixE | ALL |

Appendix B: Definitions

B.1 Abort: The successful recovery of the space flight system and its crew and passengers in the event of an anomaly that precludes mission continuance. One type of abort (intact) allows recovery without exceeding stability, control, thermal, or physiological limits, and the other type (contingency) may result in exceeding system limits in the process.

B.2 Breakout: During proximity operations, the ability to maneuver one or more vehicles to a safe separation distance.

B.3 Catastrophic Hazard: A condition that may cause death or permanently disabling injury, major system or facility destruction on the ground, or major systems or vehicle destruction during the mission.

B.4 Certification: The comprehensive evaluation of the technical and nontechnical features of a system and other safeguards, made as a part of and in support of the accreditation process, to establish the extent to which a particular design and implementation meets a set of specified requirements.

B.5 Contingency Abort: Designed to permit flight survival following severe failures when an intact abort is not possible.

B.6 Crew: Any human on board the space flight system while in flight that has been trained to interact with the space flight system; same as flight crew.

B.7 Crew and Passengers: Every human on space flight vehicle.

B.8 Crew Escape: The successful recovery of the space flight system crew and passengers in the event of an anomaly that precludes mission continuance. The space flight system in this scenario is abandoned and presumably lost.

B.9 Crew Survival: Capability and ability to keep the crew alive.

B.10 Critical Functions: Capabilities or functions that are essential to the safety of the public, crew, passengers, and/or vehicle.

B.11 Critical Software: Any software component whose failure or unanticipated performance could lead to the loss of the crew and passengers or space flight system. This includes the flight software as well as ground software that can affect flight safety.

B.12 Critical System: A system is assessed as critical if loss of overall system function, or improper performance of a system function could result in loss of life, loss of vehicle, or damage to a vehicle system.

B.13 Design for Minimum Risk: A design process or characteristic thereof such that deliberate effort is expended to maximize crew survival. Hazards not controlled by failure tolerance should be controlled by specified margins of safety, factors of safety, material properties, or any other properties inherent to the design of the part, component, subassembly, or assembly.

B.14 Deviation: A variance that authorizes departure from a particular safety requirement where the intent of the requirement is being met through alternate means that provide an equivalent level of safety.

B.15 Fail-Safe: Ability to sustain a failure and retain the capability to safely terminate or control the operation.

B.16 Flight Crew: Any human on board the space flight system while in flight that has been trained to interact with the space flight system; same as crew.

B.17 Human Health Management and Care: The set of activities, procedures, and systems that provide (1) environmental monitoring and human health assessment; (2) health maintenance and countermeasures; and (3) medical intervention for the diagnosis and treatment of injury and illness.

B.18 Human Performance: The physical and mental activity required of the crew and other participants to accomplish mission goals. This includes the interaction with equipment, computers, procedures, training material, the environment, and other humans.

B.19 Human-Rated Space System: A space system that incorporates those design features, operational procedures, and requirements necessary to accommodate human participants such that:

a. Risks have been evaluated and either eliminated or reduced to acceptable levels;

b. Human performance and health management and care have been appropriately addressed such that the system has been certified to safely support human activities; and

c. The capability to safely conduct human-tended operations has been provided, including safe recovery from any credible emergency situation.

B.20 Human-Rating: The certification that a system has been developed and is capable of being operated in a manner appropriate for use by human crews at minimal risk. Human-rated certification includes: (1) human safety; (2) human performance (both nominal and degraded states of operation); and (3) human health management and care as applicable.

B.21 Human-Rating Plan: A formal document outlining the elements and rationale for the human-rating process to be applied to a specific space flight system from SRR to system disposal at end of life. The human-rating plan is to incorporate both requirements and the verification of these requirements.

B.22 Human-Rating Process: The process steps used to achieve a human-rated system as defined in B.19. These steps include human safety risk identification, reduction, control, visibility, and program management acceptance criteria. Acceptable methods to assess the risk to human safety include qualitative and/or quantitative methods such as Hazards Analysis, Fault Tree Analysis, Human Error Analysis, Probabilistic Risk Assessment, and Failure Modes and Effects Analysis.

B.23 Human-Rating Independent Review Team: An independent group of technical experts tasked with review and concurrence of the proposed requirements, test plans, verification plans, and other program elements that constitute the basis for achieving and maintaining human rating.

B.24 Intact Abort: Recovery of the space flight system and its crew and passengers to a suitable location without exceeding stability and control, structural or thermal limits of the system, or cognitive, or physiological limits of the crew.

B.25 Intervention Capability: The ability of the crew to assert control over all space flight systems functions in nominal and off-nominal situations.

B.26 Manual Control: The ability of the crew to bypass nonessential levels of automation and exert direct control of critical space flight systems functions.

B.27 Passengers: Any human on board the space flight system while in flight that has not been trained to interact with the system and has no functional responsibility to perform any mission task for that system.

B.28 Proximity Operations: Procedures that govern space flight when two or more vehicles are operating near enough to be affected by the other.

B.29 Public: All humans not participating in the space flight activity who could be potentially affected by the function or malfunction of the space flight system.

B.30 Reliability: The probability that a system of hardware, software, and human elements will function as intended over a specified period of time under specified environmental conditions.

B.31 Safety: The minimization of risk from damage or harm to hardware, software, facilities, or humans.

B.32 Safe Haven: A functional association of capabilities and environments that is initiated and activated in the event of a potentially life-threatening anomaly and allows human survival until rescue or repair can be affected. It is usually associated with long-duration space missions and is usually implemented as a discrete location where the capabilities and environments are provided.

B.33 Space Flight System: A flight hardware and software system whose flight profile is partially or completely outside of the Earth's atmosphere.

B.34 Tailoring: The documentation and approval of the adaptation of the requirements of this document to specific program or project needs. The results of this activity are documented in the Human-Rating Plan and must be approved by the cognizant AA's.

B.35 Test Flight: A flight occurring prior to certification.

B.36 Validation: (1) An evaluation technique to support or corroborate safety requirements to ensure that necessary functions are complete and traceable; or (2) the process of evaluating software at the end of the software development process to ensure compliance with software requirements.

B.37 Variance: Documented and approved permission to perform some act or operation contrary to established requirements.

B.38 Verification: The process of proving or demonstrating that requirements have been satisfactorily met through design and/or operational elements.

B.39 Verification Plan: A formal document listing the specific technical process to be used to show compliance with each requirement.

B.40 Waiver: A variance that authorizes departure from a specific safety requirement where a certain level of risk has been documented and accepted.

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