Human Rating Concepts

Publisher Summary This chapter addresses the concept of human rating as applied to space systems. Human rating is an encompassing effort that affects many aspects of a program, from its earliest phases and throughout its life. Technical human rating requirements drive the design of flight and ground systems. In contrast, human rating programmatic requirements drive processes such as management involvement and detailed analysis, and they generate the data to support formal human rating certification. The NASA defines a human rated space system as one that “incorporates those design features, operational procedures, and requirements necessary to accommodate human participants.” A fundamental concept conveyed in this definition, is that the human rated designation is applied to a space system. In this context, a space system is defined to be “any system developed or operated that supports activity in space, including but not limited to, subsystems supporting launch, mission control, and on-orbit operations.” For the NASA Orion project, the space system includes the entire launch stack, that is, the ARES-1 launch vehicle and the Orion crew vehicle. These elements that comprise the space system are to be human rated. Should Orion be launched on a different launch vehicle or if the ARES-1 were to launch a different crewed vehicle, the entire new stack would need to be human rated as a new space system, independent of the former.