The Navy’s W93/Mk7 nuclear warhead and reentry system has entered the Engineering and Manufacturing Development (EMD) phase after achieving Milestone B, advancing the first new U.S. nuclear warhead program initiated in nearly four decades. The Navy’s Portfolio Acquisition Executive Strategic Systems Programs announced Sept. 24 that the W93/Mk7 program had entered the EMD phase of the Defense Acquisition System. A program is authorized to enter the EMD phase after achieving Milestone B, meaning it transitions from a research effort to locking in…