The Multi-role Electronically Scanned Array (MESA) is an active electronically scanned array surveillance radar system for the Boeing E-7 Wedgetail airborne early warning and control aircraft.

In the 1990s, Australia recognized a need for an airborne early warning and control (AEW&C) aircraft.

In 1996, Australia issued a request for proposal (RFP) for the aircraft for the RAAF under Project Wedgetail, referring to the Wedge-tailed eagle.

[citation needed] The L band (1 to 2 GHz) electronically scanned AEW and surveillance radar is located on a dorsal fin on top of the fuselage, dubbed the "top hat", and is designed for minimal aerodynamic effect.

When operating in look-down mode against fighter-sized target, the maximum range is in excess of 370 km.