text: Air and Missile Defense
  STATES OF READINESS
  States of readiness are alert postures for crews and systems that are tailored to the level of threat and
  warning. They are expressed as numbers, ranging from the highest state (state 1) to the lowest state (state 5).
  State 1, for instance, would be in effect when crews were engaging or would expect to imminently engage
  aerial threats; state 5 would be in effect for crews that were performing maintenance on their equipment,
  redeploying, or on crew rest. States 2 through 4 identify varying times to prepare for engagements; they are
  generally expressed in minutes. The time factors for these states often vary by system and will be expressed
  in a unit’s standard operating procedures (SOP).