Human-rating certification

Human-rated is a term used to describe the certification of a spacecraft, launch vehicle or airplane as worthy of transporting humans. NASA and the U.S. GAO now use "human-rating" when describing requirements for these systems.

In human spaceflight, a human-rating certification is the assurance that the space system accommodates human needs, effectively uses human capabilities, controls hazards with sufficient certainty to be considered safe for human operations, and provides, to the maximum extent practical, the capability to safely recover the crew from hazardous situations. In the United States, the National Aeronautics and Space Administration (NASA) has published NASA Procedural Requirement NPR 8705.2B - Human Rating Requirements for Space Systems, defining the certification process and a set of technical requirements to be applied to its crewed space systems in addition to the standards and requirements that are mandatory for all of NASA's space flight programs.

In November 2011, Ed Mango, the agency head of the NASA Commercial Crew Program (CCP), gave an extended interview on the new NASA requirements for human rating of spacecraft that will fly to the International Space Station (ISS).

The NASA CCP human-rating standards require that the probability of a loss on ascent is no more than 1 in 500, and that the probability of a loss on descent is no more than 1 in 500. The overall mission loss risk, which includes vehicle risk from micrometeorites and orbital debris while in orbit for up to 210 days, is required to be no more than 1 in 270. Maximum sustained G-loads are limited to three Earth-standard g's.

The development of the Space Shuttle and the International Space Station pre-dates the NASA Human-Rating requirements. After the Challenger and Columbia accidents, the criteria used by NASA for human-rating spacecraft have been made more stringent.

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