Core Viewpoint - The U.S. military is advancing its nuclear command and control system modernization plan, beginning tests of the next-generation "Doomsday Plane" [1][3]. Group 1: Contract and Aircraft Details - In 2024, the U.S. Air Force awarded a contract worth $13 billion to Sierra Nevada Corporation (SNC) for the procurement of five E-4C aircraft to replace the existing four E-4B aircraft [3][9]. - The E-4C aircraft will be significantly modified from the Boeing 747-8 platform, which features enhanced structural strength and reduced weight due to the use of composite materials [6][7]. - The first E-4C aircraft is expected to be delivered by 2032, continuing the U.S. Air Force's nuclear command and control tasks [9][15]. Group 2: Historical Context and Development - The U.S. was the first country to develop a "Doomsday Plane," with the E-4 aircraft first delivered in December 1974, and the E-4B variant upgraded during its service [6][9]. - The E-4C will utilize second-hand Boeing 747-8F aircraft, with the first of these expected to arrive for modification in June 2024 [7][9]. Group 3: Modernization and Strategic Importance - The modernization of the nuclear command, control, and communication (C3) systems is a critical focus for the U.S. military, with significant investments planned from 2023 to 2032 [15]. - The E-4C and the new U.S. Navy E-130J "Phoenix II" aircraft are part of a broader initiative to enhance the U.S. military's nuclear deterrence and strike capabilities [14][15]. - The integration of modern technologies such as big data and artificial intelligence into the C3 systems aims to improve the reliability and credibility of U.S. nuclear forces [15].