The B83 was based partly on the earlier B77 program, which was terminated because of cost overruns. The B77 was designed with an active altitude control and lifting parachute system for supersonic low-altitude delivery from the B-1A bomber. B77 nuclear component test firings were attributed to the Operation Anvil (Nuclear test) series in 1975 and 1976, specifically the "Cheese" test shots in Anvil: