Point of No Return is the point at which a current course of action must be continued because turning back is physically impossible, prohibitively expensive or dangerous.
Point of No Return is also referred to by pilots as the Radius of Action Formula. It originated as a technical term in air navigation to refer to the point on a flight at which, due to fuel consumption, a plane is no longer capable of returning to its airfield of original takeoff.
The Rubicon is a synonym for the Point of No Return. When Julius Caesar invaded Ancient Rome (January 10, 49 BC), he led his army across the Rubicon River in violation of law, thus making conflict inevitable.
Alea iacta est (The die is cast) is what Caesar said while crossing the Rubicon.