The 551st Electronic Systems Wing (551 ELSW) is a wing of the United States Air Force whose focus is on 'behind the scenes' electronic work. Located at Hanscom Air Force Base, Massachusetts, they work on AWACS, Joint STARS, MP-RTIP, Mission Planning, and weather systems. Now responsible for the development and sustainment of command and control systems, the 551st ELSW takes its designation from a wing that laid the foundation for modern-day airborne surveillance.