Criticality-One-R, or Crit-One-R in NASA-speak, is a term for a point of failure in the Space Shuttle which is a Criticality-One point of failure with one backup. A recent example is the wiring that was found to be loose on Endeavour's Solid Rocket Booster jettison triggering wires. Connectors to the explosive bolts holding the SRB on were loose; since each explosive bolt (used to separate the SRBs) has two identical triggering wires leading to it and is itself a Criticality-One point of failure, each wire is a Crit-One-R failure point.

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