section_path: Design/Control systems
section_name: Control systems
paragraph_text: Control systems
  
  SpaceX uses multiple redundant flight computers in a fault-tolerant design. The software runs on Linux and is written in C++. For flexibility, commercial off-the-shelf parts and system-wide radiation-tolerant design are used instead of rad-hardened parts. Each stage has stage-level flight computers, in addition to the Merlin-specific engine controllers, of the same fault-tolerant triad design to handle stage control functions. Each engine microcontroller CPU runs on a PowerPC architecture.