Big Safari is a United States Air Force program begun in 1952 which provides management, direction, and control of the acquisition, modification, and logistics support for special purpose weapons systems derived from existing aircraft and systems. To that end the program operates under procurement procedures that permit it in most cases to designate the contractor. The sole-source arrangement that allows the pairing of contractors to specific requirements is paramount to the program's success.

The program's mission statement begins:The BIG SAFARI acquisition and sustainment system employs the necessary flexibility to respond to high-priority, dynamic operational requirements for programs that involve a limited number of systems that require a rapid response to changes in the operational environment throughout the life of the system. BIG SAFARI focuses on acquiring, fielding, and sustaining key operational capabilities that otherwise would not otherwise be achievable or supportable in the required timeframe. Events and processes are tailored to meet the user's operational and schedule needs.

Now the 645th Aeronautical Systems Group (Big Safari) and aligned under the 303d Aeronautical Systems Wing, the program itself receives some direction from National Air and Space Intelligence Center (NASIC).It is headquartered in Wright-Patterson AFB and has facilities at Hanscom AFB and Greenville, Texas. The program oversees, among other aircraft, the RC-135 and EC-130 aircraft as well as unmanned aerial vehicles.

The Air Force has referred to Big Safari as a "rapid procurement force," which tests the fielding of new weapons systems, sensors, and platforms. By some accounts, the program has been operating since the late-1950s, when the BQM-34 Firefly drone was procured and evaluated. This effort led to the first operational unmanned reconnaissance vehicle, the redesignated Ryan Aeronautical AQM-34 Lightning Bug. Programs conducted under the auspices of Big Safari are identified by two-word names beginning with the word "Rivet."

The program is still operational as of 21 October 2015.