Figure 1. NASA software classification structure NASA-Wide Software ClassificationsClass A Human-Rated Space Software Systems Class B Non-Human Space-Rated Software Systems or Large-Scale Aeronautics VehiclesClass C Mission Support Software or Aeronautic Vehicles, or Major Engineering/Research Facility Software Class D Basic Science/Engineering Design and Research and Technology SoftwareClass E Design Concept, Research, Technology, and General Purpose Software Class F General Purpose Computing, Business, and IT Software Notes: It is not uncommon for a project to contain multiple systems and subsystems having different software classes.
