Submarine deterrent command under communications collapse

If a disaster killed power, communications, and many reactors, how likely would a ballistic-missile submarine launch be?

The answer considers a launch very unlikely because commanders would first investigate the widespread communications failure. The missiles could still be used because launch does not depend on GPS.

In the proposed communications-collapse scenario, submarine commanders are expected to investigate before concluding that nuclear war has begun. Silence and static across every channel could indicate a wider disruption, so the anticipated first response is to restore contact and discover what happened. This is a judgment about likely command behaviour, rather than a claim that launch would be technically impossible. Ballistic-missile launch is described as independent of GPS, with stellar positioning mentioned as an alternative navigation method. The answer deliberately leaves the detailed guidance explanation aside.